The Scientific World Journal: Ecology http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Variations in Stable Carbon Isotope Composition and Leaf Traits of Picea schrenkiana var. tianschanica along an Altitude Gradient in Tianshan Mountains, Northwest China Tue, 04 Nov 2014 08:29:22 +0000 http://www.hindawi.com/journals/tswj/2014/243159/ To understand the morphological and physiological responses of leaves to changes in altitudinal gradients, we examined ten morphological and physiological characteristics in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that LA, SD, LPC, and LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla + b, LDMC, LMA, and Narea varied nonlinearly with changes in altitude. With elevation below 2100 m, LNC, Narea, and Chla + b increased, while LDMC and LMA decreased with increasing altitude. When altitude was above 2100 m, these properties showed the opposite patterns. Leaf δ13C was positively correlated with Narea and LNC and negatively correlated with SD and LA, suggesting that leaf δ13C was indirectly controlled by physiological and morphological adjustments along altitudinal gradients. Based on the observed maximum values in LNC, Narea, Chla + b, and LA and the minimum values in LMA and LDMC at the elevation of 2100 m, suggesting higher photosynthetic capacity and greater potential for fast growth under superior optimum zone, we concluded that the best growing elevation for P. schrenkiana var. tianschanica in the Tianshan Mountains was approximately 2100 m. Huiwen Zhang, Jianying Ma, Wei Sun, and Fahu Chen Copyright © 2014 Huiwen Zhang et al. All rights reserved. Elevational Patterns of Plant Richness in the Taibai Mountain, China Tue, 28 Oct 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/309053/ The elevational distribution of plant diversity is a popular issue in ecology and biogeography, and several studies have examined the determinants behind plant diversity patterns. In this study, using published data of the local flora of Taibai Mountain, we explored the effects of spatial and climatic factors on plant species richness. We also evaluated Rapoport’s elevational rule by examining the relationship between elevational range size and midpoint. Species richness patterns were regressed against area, middle domain effect (MDE), mean annual temperature (MAT), and mean annual precipitation (MAP). The results showed that richness of overall plants, seed plants, bryophytes, and ferns all showed hump-shaped patterns along the elevational gradient, although the absolute elevation of richness peaks differed in different plant groups. Species richness of each plant group was all associated strongly with MAT and MAP. In addition to climatic factors, overall plants and seed plants were more related to area in linear regression models, while MDE was a powerful explanatory variable for bryophytes. Rapoport’s elevational rule on species richness was not supported. Our study suggests that a combined interaction of spatial and climatic factors influences the elevational patterns of plant species richness on Taibai Mountain, China. Lili Tang, Tanbao Li, Dengwu Li, and Xiaxia Meng Copyright © 2014 Lili Tang et al. All rights reserved. Analysis of Herbaceous Plant Succession and Dispersal Mechanisms in Deglaciated Terrain on Mt. Yulong, China Thu, 23 Oct 2014 08:32:23 +0000 http://www.hindawi.com/journals/tswj/2014/154539/ Ecological succession itself could be a theoretical reference for ecosystem restoration and reconstruction. Glacier forelands are ideal places for investigating plant succession because there are representative ecological succession records at long temporal scales. Based on field observations and experimental data on the foreland of Baishui number 1 Glacier on Mt. Yulong, the succession and dispersal mechanisms of dominant plant species were examined by using numerical classification and ordination methods. Fifty samples were first classified into nine community types and then into three succession stages. The three succession stages occurred about 9–13, 13–102, and 110–400 years ago, respectively. The earliest succession stage contained the association of Arenaria delavayi + Meconopsis horridula. The middle stage contained the associations of Arenaria delavayi + Kobresia fragilis, Carex capilliformis + Polygonum macrophyllum, Carex kansuensis, and also Pedicularis rupicola. The last stage included the associations of Kobresia fragilis + Carex capilliformis, Kobresia fragilis, Kobresia fragilis + Ligusticum rechingerana, and Kobresia fragilis + Ligusticum sikiangense. The tendency of the succession was from bare land to sparse vegetation and then to alpine meadow. In addition, three modes of dispersal were observed, namely, anemochory, mammalichory, and myrmecochory. The dispersal modes of dominant species in plant succession process were evolved from anemochory to zoochory. Li Chang, Yuanqing He, Taibao Yang, Jiankuo Du, Hewen Niu, and Tao Pu Copyright © 2014 Li Chang et al. All rights reserved. Sustainable Deforestation Evaluation Model and System Dynamics Analysis Thu, 28 Aug 2014 11:32:04 +0000 http://www.hindawi.com/journals/tswj/2014/106209/ The current study used the improved fuzzy analytic hierarchy process to construct a sustainable deforestation development evaluation system and evaluation model, which has refined a diversified system to evaluate the theory of sustainable deforestation development. Leveraging the visual image of the system dynamics causal and power flow diagram, we illustrated here that sustainable forestry development is a complex system that encompasses the interaction and dynamic development of ecology, economy, and society and has reflected the time dynamic effect of sustainable forestry development from the three combined effects. We compared experimental programs to prove the direct and indirect impacts of the ecological, economic, and social effects of the corresponding deforest techniques and fully reflected the importance of developing scientific and rational ecological harvesting and transportation technologies. Experimental and theoretical results illustrated that light cableway skidding is an ecoskidding method that is beneficial for the sustainable development of resources, the environment, the economy, and society and forecasted the broad potential applications of light cableway skidding in timber production technology. Furthermore, we discussed the sustainable development countermeasures of forest ecosystems from the aspects of causality, interaction, and harmony. Huirong Feng, C. W. Lim, Liqun Chen, Xinnian Zhou, Chengjun Zhou, and Yi Lin Copyright © 2014 Huirong Feng et al. All rights reserved. Study on the Response of Ecological Capacity to Land-Use/Cover Change in Wuhan City: A Remote Sensing and GIS Based Approach Thu, 28 Aug 2014 07:20:41 +0000 http://www.hindawi.com/journals/tswj/2014/794323/ This research examined the spatiotemporal patterns of land-use/cover and the dynamics of ecological capacity in response to land-use/cover change in Wuhan city, central China. The data were derived from five years’ remote-sensed images, that is, 1990, 1995, 2000, 2005, and 2010. This paper used an integrated approach of remote sensing and GIS techniques, ecological capacity and the bilateral dynamic degree models. The results are as follows. (1) From 1990 to 2010, remarkable changes in land-use/cover have occurred within the studied area, and the most prominent characteristics of the changes were continuous decline of arable land and rapid increase of built-up land. (2) The total ecological capacity dropped from in 1990 to in 2010. The eastern, western, and southern parts had higher ecological capacity whereas the northwestern hilly areas and the central district had lower ecological capacity. (3) Due to the conversion from arable land to built-up land, the ecological capacity losses during 1990–1995, 1995–2000, 2000–2005, and 2005–2010 were , , , and , respectively. The study would contribute to better understanding of the effects of land-use dynamics and the evolution of ecological capacity, which can provide scientific basis for land management and environment protection. Ying Wang, Xiangmei Li, and Jiangfeng Li Copyright © 2014 Ying Wang et al. All rights reserved. Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations Wed, 27 Aug 2014 08:48:00 +0000 http://www.hindawi.com/journals/tswj/2014/956963/ Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency () varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands. Chuanjiang Tang, Xinyu Fu, Dong Jiang, Jingying Fu, Xinyue Zhang, and Su Zhou Copyright © 2014 Chuanjiang Tang et al. All rights reserved. GIS Analysis of Land Cover Changes on the Territory of the Prokuplje Municipality Sun, 03 Aug 2014 08:32:58 +0000 http://www.hindawi.com/journals/tswj/2014/805072/ The monitoring of the territory of Prokuplje Municipality was done based on 1 : 25,000 topographic maps in three different time periods (1969, 1974, and 1984) and land cover map in 2012. Analogous topographic maps done in 1969, 1974, and 1984 were used, while in 2012 the land cover map obtained by using CORINE-like approach was used. Topographic maps are developed by aerial campaign, and today they are replaced by satellite images. Topographic maps were scanned, and raster form was transformed to vector data with Geo Media Professional 6.1 and Global Mapper software. The monitoring in the period of 1969–2012, on the area of 758300000 m2, was performed, where some parameters were analyzed. In particular, the changes of natural resources, primarily forest lands, were observed as well as the type of land susceptible to primary erosion, including the level of urbanization and level of agricultural land. The obtained results clearly showed changes in forestation within the 43-year-long period, as well as changes in primary erosion and urbanization, while at the level of agricultural land, slight changes were found. The paper also involved transition of social factors from 1969 to 2012, expressed as a change between the earth and forest layer. Aleksandar Valjarević, Dragica Živković, Dragana Valjarević, Vladica Stevanović, and Jelena Golijanin Copyright © 2014 Aleksandar Valjarević et al. All rights reserved. Prescribed Burning and Clear-Cutting Effects on Understory Vegetation in a Pinus canariensis Stand (Gran Canaria) Thu, 24 Jul 2014 07:52:33 +0000 http://www.hindawi.com/journals/tswj/2014/215418/ Prescribed fires are a powerful tool for reducing fire hazards by decreasing amounts of fuel. The main objective is to analyze the effects of prescribed burning on the understory vegetation composition as well as on the soil characteristics of a reforested stand of Pinus canariensis. The study attempts to identify the effects of the preburning treatment of cutting understory vegetation on the floristic parameters of the vegetation community. This study was carried out for two years following a prescribed fire in a Canarian pine stand. Cutting and burning treatment affected species composition and increased diversity. Burnt and cut plots were characterized by a diverse array of herbaceous species and by a lower abundance of Teline microphylla (endemic legume), although burning apparently induced its germination. Cut treatment was more consistently differentiated from the control plots than burnt treatment. Soil K decreased after both treatments, pH slightly decreased after cutting, while P and Ca increased after fire. From an ecological point of view, prescribed burning is a better management practice than cutting the woody species of the understory. However, long-term studies would be necessary to evaluate the effects of fire intensity, season and frequency in which the prescribed burning is applied. José Ramón Arévalo, Silvia Fernández-Lugo, Celia García-Domínguez, Agustín Naranjo-Cigala, Federico Grillo, and Leonor Calvo Copyright © 2014 José Ramón Arévalo et al. All rights reserved. Prediction of the Reference Evapotranspiration Using a Chaotic Approach Wed, 16 Jul 2014 12:09:05 +0000 http://www.hindawi.com/journals/tswj/2014/347625/ Evapotranspiration is one of the most important hydrological variables in the context of water resources management. An attempt was made to understand and predict the dynamics of reference evapotranspiration from a nonlinear dynamical perspective in this study. The reference evapotranspiration data was calculated using the FAO Penman-Monteith equation with the observed daily meteorological data for the period 1966–2005 at four meteorological stations (i.e., Baotou, Zhangbei, Kaifeng, and Shaoguan) representing a wide range of climatic conditions of China. The correlation dimension method was employed to investigate the chaotic behavior of the reference evapotranspiration series. The existence of chaos in the reference evapotranspiration series at the four different locations was proved by the finite and low correlation dimension. A local approximation approach was employed to forecast the daily reference evapotranspiration series. Low root mean square error (RSME) and mean absolute error (MAE) (for all locations lower than 0.31 and 0.24, resp.), high correlation coefficient (CC), and modified coefficient of efficiency (for all locations larger than 0.97 and 0.8, resp.) indicate that the predicted reference evapotranspiration agrees well with the observed one. The encouraging results indicate the suitableness of chaotic approach for understanding and predicting the dynamics of the reference evapotranspiration. Wei-guang Wang, Shan Zou, Zhao-hui Luo, Wei Zhang, Dan Chen, and Jun Kong Copyright © 2014 Wei-guang Wang et al. All rights reserved. Modelling Hydrology of a Single Bioretention System with HYDRUS-1D Tue, 15 Jul 2014 07:56:33 +0000 http://www.hindawi.com/journals/tswj/2014/521047/ A study was carried out on the effectiveness of bioretention systems to abate stormwater using computer simulation. The hydrologic performance was simulated for two bioretention cells using HYDRUS-1D, and the simulation results were verified by field data of nearly four years. Using the validated model, the optimization of design parameters of rainfall return period, filter media depth and type, and surface area was discussed. And the annual hydrologic performance of bioretention systems was further analyzed under the optimized parameters. The study reveals that bioretention systems with underdrains and impervious boundaries do have some detention capability, while their total water retention capability is extremely limited. Better detention capability is noted for smaller rainfall events, deeper filter media, and design storms with a return period smaller than 2 years, and a cost-effective filter media depth is recommended in bioretention design. Better hydrologic effectiveness is achieved with a higher hydraulic conductivity and ratio of the bioretention surface area to the catchment area, and filter media whose conductivity is between the conductivity of loamy sand and sandy loam, and a surface area of 10% of the catchment area is recommended. In the long-term simulation, both infiltration volume and evapotranspiration are critical for the total rainfall treatment in bioretention systems. Yingying Meng, Huixiao Wang, Jiangang Chen, and Shuhan Zhang Copyright © 2014 Yingying Meng et al. All rights reserved. Bird Diversity and Distribution in relation to Urban Landscape Types in Northern Rwanda Tue, 15 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/157824/ Using the point count method, linear mixed models, Shannon’s diversity index, and Bray-Curtis cluster analysis, we conducted a study of the effect of urban fabric layout on bird diversity and distribution in northern Rwanda. The results showed a significant effect of city landscapes on bird richness and relative abundance; residential neighborhoods, institutional grounds, and informal settlements had the highest species diversity in comparison to other microlandscape types. Riversides were characterized by specialized bird species, commonly known to be restricted to wetland environments. Built-up areas and open field landscapes had comparable results. One Albertine Rift endemic bird species, the Ruwenzori Double-collared Sunbird (Cinnyris stuhlmanni), was recorded. Three migratory birds were found in Musanze city for the first time: the Common Sandpiper (Actitis hypoleucos), the Spotted Flycatcher (Muscicapa striata), and the Willow Warbler (Phylloscopus trochilus). Two bird species have not been previously reported in Rwanda: the Garden Warbler (Sylvia borin) and the Lesser Spotted Eagle (Aquila pomarina). The implications of this study are particularly relevant to urban decision makers who should consider the existence of a great diversity of avian fauna when developing and implementing master plans, especially when villages and cities are in proximity of protected areas or natural reserves. T. Gatesire, D. Nsabimana, A. Nyiramana, J. L. Seburanga, and M. O. Mirville Copyright © 2014 T. Gatesire et al. All rights reserved. Natural Recovery and Planned Intervention in Coastal Wetlands: Venice Lagoon (Northern Adriatic Sea, Italy) as a Case Study Sun, 13 Jul 2014 07:16:19 +0000 http://www.hindawi.com/journals/tswj/2014/968618/ The goals of conservation and sustainable use of environmental ecosystems have increased the need for detailed knowledge of ecological evolution and responses to both anthropogenic pressures and recovery measures. The present study shows the effects of natural processes and planned intervention in terms of reducing nutrient inputs in a highly exploited coastal lagoon, describing its evolution over a 16-year period from the late 1980s (when eutrophication was at its peak) until 2003. Changes in nutrient and carbon concentrations in the top layer of sediments were investigated in parallel with macroalgal and seagrass biomass in the most anthropized basin of Venice Lagoon in four surveys conducted in accordance with the same protocols in 1987, 1993, 1998, and 2003. A pronounced reduction in trophic state (mainly total nitrogen, organic phosphorus, and organic carbon concentrations) and macroalgal biomass was recorded, together with the progressive expansion of seagrass meadows. General considerations are also made on the effects of Manila clam farming and the shift from illegal to managed clam farming. Chiara Facca, Sonia Ceoldo, Nicola Pellegrino, and Adriano Sfriso Copyright © 2014 Chiara Facca et al. All rights reserved. Differential Responses of Net Ecosystem Exchange of Carbon Dioxide to Light and Temperature between Spring and Neap Tides in Subtropical Mangrove Forests Tue, 08 Jul 2014 10:57:55 +0000 http://www.hindawi.com/journals/tswj/2014/943697/ The eddy flux data with field records of tidal water inundation depths of the year 2010 from two mangroves forests in southern China were analyzed to investigate the tidal effect on mangrove carbon cycle. We compared the net ecosystem exchange (NEE) and its responses to light and temperature, respectively, between spring tide and neap tide inundation periods. For the most time of the year 2010, higher daytime NEE values were found during spring tides than during neap tides at both study sites. Regression analysis of daytime NEE to photosynthetically active radiation (PAR) using the Landsberg model showed increased sensitivity of NEE to PAR with higher maximum photosynthetic rate during spring tides than neap tides. In contrast, the light compensation points acquired from the regression function of the Landsberg model were smaller during spring tides than neap tides in most months. The dependence of nighttime NEE on soil temperature was lower under spring tide than under neap tides. All these results above indicated that ecosystem carbon uptake rates of mangrove forests were strengthened, while ecosystem respirations were inhibited during spring tides in comparison with those during neap tides, which needs to be considered in modeling mangrove ecosystem carbon cycle under future sea level rise scenarios. Qing Li, Weizhi Lu, Hui Chen, Yiqi Luo, and Guanghui Lin Copyright © 2014 Qing Li et al. All rights reserved. Changes in Stream Peak Flow and Regulation in Naoli River Watershed as a Result of Wetland Loss Mon, 07 Jul 2014 09:07:01 +0000 http://www.hindawi.com/journals/tswj/2014/209547/ Hydrology helps determine the character of wetlands; wetlands, in turn, regulate water flow, which influences regional hydrology. To understand these dynamics, we studied the Naoli basin where, from 1954 to 2005, intensive marshland cultivation took place, and the watershed’s wetland area declined from  ha to  ha. More than 80% of the wetland area loss was due to conversion to farmland, especially from 1976 to 1986. The processes of transforming wetlands to cultivated land in the whole Naoli basin and subbasins can be described using a first order exponential decay model. To quantify the effects of wetlands cultivation, we analyzed daily rainfall and streamflow data measured from 1955 to 2005 at two stations (Baoqing Station and Caizuizi Station). We defined a streamflow regulation index (SRI) and applied a Mann-Kendall-Sneyers test to further analyze the data. As the wetland area decreased, the peak streamflow at the Caizuizi station increased, and less precipitation generated heavier peak flows, as the runoff was faster than before. The SRI from 1959 to 2005 showed an increasing trend; the SRI rate of increase was 0.05/10a, demonstrating that the watershed’s regulation of streamflow regulation was declined as the wetlands disappeared. Yunlong Yao, Lei Wang, Xianguo Lv, Hongxian Yu, and Guofu Li Copyright © 2014 Yunlong Yao et al. All rights reserved. Comparative Analyses of Physiological Responses of Cynodon dactylon Accessions from Southwest China to Sulfur Dioxide Toxicity Sun, 06 Jul 2014 10:43:10 +0000 http://www.hindawi.com/journals/tswj/2014/916595/ Sulfur dioxide (SO2), a major air pollutant in developing countries, is highly toxic to plants. To achieve better air quality and landscape, planting appropriate grass species in severe SO2 polluted areas is very critical. Cynodon dactylon, a widely used warm season turfgrass species, has good SO2-tolerant ability. In this study, we selected 9 out of 38 C. dactylon accessions from Southwest China as representatives of high, intermediate SO2-tolerant and SO2-sensitive accessions to comparatively analyze their physiological differences in leaves under SO2 untreated and treated conditions. Our results revealed that SO2-tolerant C. dactylon accessions showed higher soluble sugar, proline, and chlorophyll a contents under both SO2 treated and untreated conditions; higher chlorophyll b and carotenoid under SO2 treated condition; lower reactive oxygen species (ROS) level, oxidative damages, and superoxide dismutase (SOD) activities under SO2 treated condition; and higher peroxidase (POD) activities under SO2 untreated condition. Further results indicated that SO2-tolerant C. dactylon accessions had higher sulfur contents under both SO2 treated and untreated conditions, consistent with higher SO activities under both SO2 treated and untreated conditions, and higher SiR activities under SO2 treated condition. Taken together, our results indicated that SO2 tolerance of C. dactylon might be largely related to soluble sugar, proline and chlorophyll a contents, and SO enzyme activity. Xi Li, Ling Wang, Yiqiao Li, Lingxia Sun, Shizhen Cai, and Zhuo Huang Copyright © 2014 Xi Li et al. All rights reserved. The Influences of Canopy Species and Topographic Variables on Understory Species Diversity and Composition in Coniferous Forests Sun, 06 Jul 2014 07:38:57 +0000 http://www.hindawi.com/journals/tswj/2014/252489/ Understanding the factors that influence the distribution of understory vegetation is important for biological conservation and forest management. We compared understory species composition by multi-response permutation procedure and indicator species analysis between plots dominated by Qinghai spruce (Picea crassifolia Kom.) and Qilian juniper (Sabina przewalskii Kom.) in coniferous forests of the Qilian Mountains, northwestern China. Understory species composition differed markedly between the forest types. Many heliophilous species were significantly associated with juniper forest, while only one species was indicative of spruce forest. Using constrained ordination and the variation partitioning model, we quantitatively assessed the relative effects of two sets of explanatory variables on understory species composition. The results showed that topographic variables had higher explanatory power than did site conditions for understory plant distributions. However, a large amount of the variation in understory species composition remained unexplained. Forward selection revealed that understory species distributions were primarily affected by elevation and aspect. Juniper forest had higher species richness and α-diversity and lower β-diversity in the herb layer of the understory plant community than spruce forest, suggesting that the former may be more important in maintaining understory biodiversity and community stability in alpine coniferous forest ecosystems. Hong Huo, Qi Feng, and Yong-hong Su Copyright © 2014 Hong Huo et al. All rights reserved. Facilitative and Inhibitory Effect of Litter on Seedling Emergence and Early Growth of Six Herbaceous Species in an Early Successional Old Field Ecosystem Tue, 01 Jul 2014 06:55:29 +0000 http://www.hindawi.com/journals/tswj/2014/101860/ In the current study, a field experiment was conducted to examine effects of litter on seedling emergence and early growth of four dominant weed species from the early successional stages of old field ecosystem and two perennial grassland species in late successional stages. Our results showed that increased litter cover decreased soil temperature and temperature variability over time and improved soil moisture status. Surface soil electrical conductivity increased as litter increased. The increased litter delayed seedling emergence time and rate. The emergence percentage of seedlings and establishment success rate firstly increased then decreased as litter cover increased. When litter biomass was below 600 g m−2, litter increased seedlings emergence and establishment success in all species. With litter increasing, the basal diameter of seedling decreased, but seedling height increased. Increasing amounts of litter tended to increase seedling dry weight and stem leaf ratio. Different species responded differently to the increase of litter. Puccinellia tenuiflora and Chloris virgata will acquire more emergence benefits under high litter amount. It is predicted that Chloris virgata will dominate further in this natural succession old field ecosystem with litter accumulation. Artificial P. tenuiflora seeds addition may be required to accelerate old field succession toward matured grassland. Qiang Li, Pujia Yu, Xiaoying Chen, Guangdi Li, Daowei Zhou, and Wei Zheng Copyright © 2014 Qiang Li et al. All rights reserved. From Maximization to Optimization: A Paradigm Shift in Rice Production in Thailand to Improve Overall Quality of Life of Stakeholders Sun, 29 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/604291/ The concept of crop yield maximization has been widely supported. In practice, however, yield maximization does not necessarily lead to maximum socioeconomic welfare. Optimization is therefore necessary to ensure quality of life of farmers and other stakeholders. In Thailand, a rice farmers' network has adopted a promising agricultural system aimed at the optimization of rice farming. Various feasible techniques were flexibly combined. The new system offers technical strengths and minimizes certain difficulties with which the rice farmers once struggled. It has resulted in fairly good yields of up to 8.75 t ha−1 or yield increases of up to 57% (from 4.38 to 6.88 t ha−1). Under the optimization paradigm, the farmers have established diversified sustainable relationships with the paddy fields in terms of ecosystem management through their own self-motivated scientific observations. The system has resulted in good health conditions for the farmers and villagers, financial security, availability of extra time, and additional opportunities and freedom and hence in the improvement of their overall quality of life. The underlying technical and social mechanisms are discussed herein. Ryoichi Doi and Supachai Pitiwut Copyright © 2014 Ryoichi Doi and Supachai Pitiwut. All rights reserved. Foliar Water Uptake of Tamarix ramosissima from an Atmosphere of High Humidity Tue, 27 May 2014 10:09:33 +0000 http://www.hindawi.com/journals/tswj/2014/529308/ Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH) was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants. Shuang Li, Hong-lang Xiao, Liang Zhao, Mao-Xian Zhou, and Fang Wang Copyright © 2014 Shuang Li et al. All rights reserved. Monitoring the Invasion of Spartina alterniflora Using Very High Resolution Unmanned Aerial Vehicle Imagery in Beihai, Guangxi (China) Sun, 04 May 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/638296/ Spartina alterniflora was introduced to Beihai, Guangxi (China), for ecological engineering purposes in 1979. However, the exceptional adaptability and reproductive ability of this species have led to its extensive dispersal into other habitats, where it has had a negative impact on native species and threatens the local mangrove and mudflat ecosystems. To obtain the distribution and spread of Spartina alterniflora, we collected HJ-1 CCD imagery from 2009 and 2011 and very high resolution (VHR) imagery from the unmanned aerial vehicle (UAV). The invasion area of Spartina alterniflora was 357.2 ha in 2011, which increased by 19.07% compared with the area in 2009. A field survey was conducted for verification and the total accuracy was 94.0%. The results of this paper show that VHR imagery can provide details on distribution, progress, and early detection of Spartina alterniflora invasion. OBIA, object based image analysis for remote sensing (RS) detection method, can enable control measures to be more effective, accurate, and less expensive than a field survey of the invasive population. Huawei Wan, Qiao Wang, Dong Jiang, Jingying Fu, Yipeng Yang, and Xiaoman Liu Copyright © 2014 Huawei Wan et al. All rights reserved. Land Use Changes and Their Effects on the Value of Ecosystem Services in the Small Sanjiang Plain in China Sun, 09 Mar 2014 14:10:14 +0000 http://www.hindawi.com/journals/tswj/2014/752846/ The small Sanjiang plain is one of the most important commodity grain production bases and the largest fresh water wetland in China. Due to the rapid expansion of agricultural activities in the past 30 years, the contradiction between economic development and the loss of ecosystem services has become an issue of increasing concern in the area. In this study, we analysed land use changes and the loss of ecosystem services value caused by these changes. We found that cropland sprawl was predominant and occurred in forest, wetland, and grassland areas in the small Sanjiang plain from 1980 to 2010. Using a model to evaluate ecosystem services value, we calculated that the decreased values of ecosystem services were 169.88 × 108 Yuan from 1980 to 2000 and 120.00 × 108 Yuan from 2000 to 2010. All of the ecosystem services were diminished from 1980 to 2010 except for food production. Therefore, the loss of ecosystem services value should be considered by the policymakers of land use and development. Jing Chen, Bo-Ming Sun, Dan Chen, Xin Wu, Long-Zhu Guo, and Gang Wang Copyright © 2014 Jing Chen et al. All rights reserved. Estimating Tree Height-Diameter Models with the Bayesian Method Tue, 25 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2014/683691/ Six candidate height-diameter models were used to analyze the height-diameter relationships. The common methods for estimating the height-diameter models have taken the classical (frequentist) approach based on the frequency interpretation of probability, for example, the nonlinear least squares method (NLS) and the maximum likelihood method (ML). The Bayesian method has an exclusive advantage compared with classical method that the parameters to be estimated are regarded as random variables. In this study, the classical and Bayesian methods were used to estimate six height-diameter models, respectively. Both the classical method and Bayesian method showed that the Weibull model was the “best” model using data1. In addition, based on the Weibull model, data2 was used for comparing Bayesian method with informative priors with uninformative priors and classical method. The results showed that the improvement in prediction accuracy with Bayesian method led to narrower confidence bands of predicted value in comparison to that for the classical method, and the credible bands of parameters with informative priors were also narrower than uninformative priors and classical method. The estimated posterior distributions for parameters can be set as new priors in estimating the parameters using data2. Xiongqing Zhang, Aiguo Duan, Jianguo Zhang, and Congwei Xiang Copyright © 2014 Xiongqing Zhang et al. All rights reserved. Assessing the Impact of Policy Changes in the Icelandic Cod Fishery Using a Hybrid Simulation Model Mon, 24 Feb 2014 12:44:23 +0000 http://www.hindawi.com/journals/tswj/2014/707943/ Most of the Icelandic cod is caught in bottom trawlers or longliners. These two fishing methods are fundamentally different and have different economic, environmental, and even social effects. In this paper we present a hybrid-simulation framework to assess the impact of changing the ratio between cod quota allocated to vessels with longlines and vessels with bottom trawls. It makes use of conventional bioeconomic models and discrete event modelling and provides a framework for simulating life cycle assessment (LCA) for a cod fishery. The model consists of two submodels, a system dynamics model describing the biological aspect of the fishery and a discrete event model for fishing activities. The model was run multiple times for different quota allocation scenarios and results are presented where different scenarios are presented in the three dimensions of sustainability: environmental, social, and economic. The optimal allocation strategy depends on weighing the three different factors. The results were encouraging first-steps towards a useful modelling method but the study would benefit greatly from better data on fishing activities. Sigríður Sigurðardóttir, Björn Johansson, Sveinn Margeirsson, and Jónas R. Viðarsson Copyright © 2014 Sigríður Sigurðardóttir et al. All rights reserved. Spatial Heterogeneity of Soil Chemical Properties in a Subtropical Karst Forest, Southwest China Wed, 12 Feb 2014 09:44:40 +0000 http://www.hindawi.com/journals/tswj/2014/473651/ This study evaluates the spatial heterogeneity of the soil chemical properties of surface soils across a 1 ha old-growth subtropical karst forest in southwest China. Zhonghua Zhang, Baoqing Hu, and Gang Hu Copyright © 2014 Zhonghua Zhang et al. All rights reserved. Harmful Algae Records in Venice Lagoon and in Po River Delta (Northern Adriatic Sea, Italy) Mon, 10 Feb 2014 09:09:55 +0000 http://www.hindawi.com/journals/tswj/2014/806032/ A detailed review of harmful algal blooms (HAB) in northern Adriatic Sea lagoons (Po River Delta and Venice lagoon) is presented to provide “updated reference conditions” for future research and monitoring activities. In the study areas, the high mollusc production requires the necessity to identify better methods able to prevent risks for human health and socioeconomical interests. So, an integrated approach for the identification and quantification of algal toxins is presented by combining microscopy techniques with Liquid Chromatography coupled with High Resolution Time of Flight Mass Spectrometry (HPLC-HR-TOF-MS). The method efficiency was first tested on some samples from the mentioned coastal areas, where Dinophysis spp. occurred during summer in the sites directly affected by seawaters. Although cell abundance was always <200 cells/L, the presence of Pectenotoxin-2 (PTX2), detected by HPLC-HR-TOF-MS, indicated the potential release of detectable amounts of toxins even at low cell abundance. Chiara Facca, Dagmar Bilaničovà, Giulio Pojana, Adriano Sfriso, and Antonio Marcomini Copyright © 2014 Chiara Facca et al. All rights reserved. Body Size Mediated Coexistence in Swans Tue, 04 Feb 2014 07:23:04 +0000 http://www.hindawi.com/journals/tswj/2014/643694/ Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource. Katharina A. M. Engelhardt, Mark E. Ritchie, and James A. Powell Copyright © 2014 Katharina A. M. Engelhardt et al. All rights reserved. Seasonal Changes of Fish Assemblages in a Subtropical Lagoon in the SE Gulf of California Mon, 27 Jan 2014 09:08:09 +0000 http://www.hindawi.com/journals/tswj/2014/968902/ The composition and seasonal changes of the fish assemblage in a coastal lagoon system in southeastern Gulf of California were assessed from December 2001 to July 2005. A total of 20,877 organisms belonging to 191 species and 47 families were analyzed. We determined that almost all the species inhabiting the system were found; however some rare species were not captured in our study. The majority of the species found were demersal but in every season at least one pelagic or benthopelagic species showed high abundances. The moonfish, Selene peruviana, was the most abundant species, whilst the puffer, Sphoeroides annulatus, was the main species in terms of biomass. The species composition changed seasonally; results from the Simpson diversity index and the cumulative species curve show that seasonally almost all the species in the system for a given season were found. These changes were also reflected in the multivariate results. The seasonal variations could be attributed to the migration of species out of the system as they grow and the arrival of new ones, which could also be related to temperature patterns since this environmental factor changes considerably through the year. F. Amezcua and F. Amezcua-Linares Copyright © 2014 F. Amezcua and F. Amezcua-Linares. All rights reserved. Seasonality Influence on Biochemical and Hematological Indicators of Stress and Growth of Pirarucu (Arapaima gigas), an Amazonian Air-Breathing Fish Tue, 21 Jan 2014 11:19:18 +0000 http://www.hindawi.com/journals/tswj/2014/541278/ Environmental factors such as seasonal cycles are the main chronic stress cause in fish increasing incidence of disease and mortality and affecting productive performance. Arapaima gigas (pirarucu) is an Amazonian air-breathing and largest freshwater fish with scales in the world. The captivity development of pirarucu is expanding since it can fatten up over 1 kg per month reaching 10 kg body mass in the first year of fattening. This work was conducted in three periods (April to July 2010, August to November 2010, and December 2010 to March 2011) defined according to rainfall and medium temperatures. Seasonality effect analysis was performed on biochemical (lectin activity, lactate dehydrogenase, and alkaline phosphatase activities) and hematological (total count of red blood cells, hematocrit, hemoglobin, and hematimetric Wintrobe indexes) stress indicators, as well as on growth and wellbeing degree expressed by pirarucu condition factor developed in captivity. All biochemical and hematological stress indicators showed seasonal variations. However, the fish growth was allometrically positive; condition factor high values indicated good state of healthiness in cultivation. These results reinforce the robust feature of pirarucu and represent a starting point for understanding stress physiology and environmental changes during cultivation enabling identification and prevention of fish adverse health conditions. Rosiely Felix Bezerra, Maria do Carmo Figueiredo Soares, Athiê Jorge Guerra Santos, Elba Verônica Matoso Maciel Carvalho, and Luana Cassandra Breitenbach Barroso Coelho Copyright © 2014 Rosiely Felix Bezerra et al. All rights reserved. Responses of Ecosystem CO2 Fluxes to Short-Term Experimental Warming and Nitrogen Enrichment in an Alpine Meadow, Northern Tibet Plateau Sun, 29 Dec 2013 11:27:01 +0000 http://www.hindawi.com/journals/tswj/2013/415318/ Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming. N addition, warming, N addition × warming, and a control were set up. In OTCs, daytime air and soil temperature were warmed by 2.0°C and 1.6°C above ambient conditions, but soil moisture was decreased by 4.95 m3 m−3. N addition enhanced ecosystem respiration (Reco); nevertheless, warming significantly decreased Reco. The decline of Reco resulting from warming was cancelled out by N addition in late growing season. Our results suggested that N addition enhanced Reco by increasing soil N availability and plant production, whereas warming decreased Reco through lowering soil moisture, soil N supply potential, and suppression of plant activity. Furthermore, season-specific responses of Reco indicated that warming and N deposition caused by future global change may have complicated influence on carbon cycles in alpine ecosystems. Ning Zong, Peili Shi, Jing Jiang, Minghua Song, Dingpeng Xiong, Weiling Ma, Gang Fu, Xianzhou Zhang, and Zhenxi Shen Copyright © 2013 Ning Zong et al. All rights reserved. Reduction of the Livestock Ammonia Emission under the Changing Temperature during the Initial Manure Nitrogen Biomineralization Mon, 23 Dec 2013 16:15:06 +0000 http://www.hindawi.com/journals/tswj/2013/825437/ Experimental data were applied for the modelling optimal cowshed temperature environment in laboratory test bench by a mass-flow method. The principal factor affecting exponent growth of ammonia emission was increasing air and manure surface temperature. With the manure temperature increasing from 4°C to 30°C, growth in the ammonia emission grew fourfold, that is, from 102 to 430 mg m−2h−1. Especial risk emerges when temperature exceeds 20°C: an increase in temperature of 1°C contributes to the intensity of ammonia emission by 17 mg m−2h−1. The temperatures of air and manure surface as well as those of its layers are important when analysing emission processes from manure. Indeed, it affects the processes occurring on the manure surface, namely, dehydration and crust formation. To reduce ammonia emission from cowshed, it is important to optimize the inner temperature control and to manage air circulation, especially at higher temperatures, preventing the warm ambient air from blowing direct to manure. Decrease in mean annual temperature of 1°C would reduce the annual ammonia emission by some 5.0%. The air temperature range varied between −15°C and 30°C in barns. The highest mean annual temperature (14.6°C) and ammonia emission (218 mg m−2h−1) were observed in the semideep cowshed. Rolandas Bleizgys, Indrė Bagdonienė, and Ligita Baležentienė Copyright © 2013 Rolandas Bleizgys et al. All rights reserved. Wetland Degradation and Ecological Restoration Tue, 10 Dec 2013 09:42:50 +0000 http://www.hindawi.com/journals/tswj/2013/523632/ Junhong Bai, Baoshan Cui, Huicong Cao, Ainong Li, and Baiyu Zhang Copyright © 2013 Junhong Bai et al. All rights reserved. Total Economic Value of Wetlands Products and Services in Uganda Sun, 15 Sep 2013 09:20:45 +0000 http://www.hindawi.com/journals/tswj/2013/192656/ Wetlands provide food and non-food products that contribute to income and food security in Uganda. This study determined the economic value of wetland resources and their contribution to food security in the three agroecological zones of Uganda. The values of wetland resources were estimated using primary and secondary data. Market price, Productivity, and Contingent valuation methods were used to estimate the value of wetland resources. The per capita value of fish was approximately US$ 0.49 person−1. Fish spawning was valued at approximately US$ 363,815 year−1, livestock pastures at US$ 4.24 million, domestic water use at US$ 34 million year−1, and the gross annual value added by wetlands to milk production at US$ 1.22 million. Flood control was valued at approximately US$ 1,702,934,880 hectare−1 year−1 and water regulation and recharge at US$ 7,056,360 hectare−1 year−1. Through provision of grass for mulching, wetlands were estimated to contribute to US$ 8.65 million annually. The annual contribution of non-use values was estimated in the range of US$ 7.1 million for water recharge and regulation and to US$ 1.7 billion for flood control. Thus, resource investment for wetlands conservation is economically justified to create incentives for continued benefits. Willy Kakuru, Nelson Turyahabwe, and Johnny Mugisha Copyright © 2013 Willy Kakuru et al. All rights reserved. The Ecological Response of Carex lasiocarpa Community in the Riparian Wetlands to the Environmental Gradient of Water Depth in Sanjiang Plain, Northeast China Mon, 26 Aug 2013 11:08:27 +0000 http://www.hindawi.com/journals/tswj/2013/402067/ The response of Carex lasiocarpa in riparian wetlands in Sanjiang Plain to the environmental gradient of water depth was analyzed by using the Gaussian Model based on the biomass and average height data, and the ecological water-depth amplitude of Carex lasiocarpa was derived. The results indicated that the optimum ecological water-depth amplitude of Carex lasiocarpa based on biomass was [13.45 cm, 29.78 cm], while the optimum ecological water-depth amplitude of Carex lasiocarpa based on average height was [2.31 cm, 40.11 cm]. The intersection of the ecological water-depth amplitudes based on biomass and height confirmed that the optimum ecological water-depth amplitude of Carex lasiocarpa was [13.45 cm, 29.78 cm] and the optimist growing water-depth of Carex lasiocarpa was 21.4 cm. The TWINSPAN, a polythetic and divisive classification tool, was used to classify the wetland ecological series into 6 associations. Result of TWINSPAN matrix classification reflected an obvious environmental gradient in these associations: water-depth gradient. The relation of biodiversity of Carex lasiocarpa community and water depth was determined by calculating the diversity index of each association. Zhaoqing Luan, Zhongxin Wang, Dandan Yan, Guihua Liu, and Yingying Xu Copyright © 2013 Zhaoqing Luan et al. All rights reserved. Gap Analysis and Conservation Network for Freshwater Wetlands in Central Yangtze Ecoregion Sun, 25 Aug 2013 09:03:03 +0000 http://www.hindawi.com/journals/tswj/2013/918718/ The Central Yangtze Ecoregion contains a large area of internationally important freshwater wetlands and supports a huge number of endangered waterbirds; however, these unique wetlands and the biodiversity they support are under the constant threats of human development pressures, and the prevailing conservation strategies generated based on the local scale cannot adequately be used as guidelines for ecoregion-based conservation initiatives for Central Yangtze at the broad scale. This paper aims at establishing and optimizing an ecological network for freshwater wetland conservation in the Central Yangtze Ecoregion based on large-scale gap analysis. A group of focal species and GIS-based extrapolation technique were employed to identify the potential habitats and conservation gaps, and the optimized conservation network was then established by combining existing protective system and identified conservation gaps. Our results show that only 23.49% of the potential habitats of the focal species have been included in the existing nature reserves in the Central Yangtze Ecoregion. To effectively conserve over 80% of the potential habitats for the focal species by optimizing the existing conservation network for the freshwater wetlands in Central Yangtze Ecoregion, it is necessary to establish new wetland nature reserves in 22 county units across Hubei, Anhui, and Jiangxi provinces. Li Xiaowen, Zhuge Haijin, and Mengdi Li Copyright © 2013 Li Xiaowen et al. All rights reserved. Impacts of Intensified Agriculture Developments on Marsh Wetlands Tue, 20 Aug 2013 09:39:04 +0000 http://www.hindawi.com/journals/tswj/2013/409439/ A spatiotemporal analysis on the changes in the marsh landscape in the Honghe National Nature Reserve, a Ramsar reserve, and the surrounding farms in the core area of the Sanjiang Plain during the past 30 years was conducted by integrating field survey work with remote sensing techniques. The results indicated that intensified agricultural development had transformed a unique natural marsh landscape into an agricultural landscape during the past 30 years. Ninety percent of the natural marsh wetlands have been lost, and the areas of the other natural landscapes have decreased very rapidly. Most dry farmland had been replaced by paddy fields during the progressive change of the natural landscape to a farm landscape. Attempts of current Chinese institutions in preserving natural wetlands have achieved limited success. Few marsh wetlands have remained healthy, even after the establishment of the nature reserve. Their ecological qualities have been declining in response to the increasing threats to the remaining wetland habitats. Irrigation projects play a key role in such threats. Therefore, the sustainability of the natural wetland ecosystems is being threatened by increased regional agricultural development which reduced the number of wetland ecotypes and damaged the ecological quality. Zhaoqing Luan and Demin Zhou Copyright © 2013 Zhaoqing Luan and Demin Zhou. All rights reserved. Polder Effects on Sediment-to-Soil Conversion: Water Table, Residual Available Water Capacity, and Salt Stress Interdependence Mon, 05 Aug 2013 13:55:05 +0000 http://www.hindawi.com/journals/tswj/2013/451710/ The French Atlantic marshlands, reclaimed since the Middle Age, have been successively used for extensive grazing and more recently for cereal cultivation from 1970. The soils have acquired specific properties which have been induced by the successive reclaiming and drainage works and by the response of the clay dominant primary sediments, that is, structure, moisture, and salinity profiles. Based on the whole survey of the Marais Poitevin and Marais de Rochefort and in order to explain the mechanisms of marsh soil behavior, the work focuses on two typical spots: an undrained grassland since at least 1964 and a drained cereal cultivated field. The structure-hydromechanical profiles relationships have been established thanks to the clay matrix shrinkage curve. They are confronted to the hydraulic functioning including the fresh-to-salt water transfers and to the recording of tensiometer profiles. The CE1/5 profiles supply the water geochemical and geophysical data by their better accuracy. Associated to the available water capacity calculation they allow the representation of the parallel evolution of the residual available water capacity profiles and salinity profiles according to the plant growing and rooting from the mesophile systems of grassland to the hygrophile systems of drained fields. Raymond Tojo Radimy, Patrick Dudoignon, Jean Michel Hillaireau, and Elise Deboute Copyright © 2013 Raymond Tojo Radimy et al. All rights reserved. Phytoplankton and Eutrophication Degree Assessment of Baiyangdian Lake Wetland, China Thu, 25 Jul 2013 08:25:35 +0000 http://www.hindawi.com/journals/tswj/2013/436965/ Eight typical sampling sites were chosen to investigate the phytoplankton community structure and to assess the eutrophication degree of Baiyangdian Lake in 2009. Our results showed that among the total 133 species identified, Cyanophyta, Chlorophyta, and Bacillariophyta dominated the phytoplankton community. In spring, Chlorophyta and Bacillariophyta were the dominant phyla, and the dominant species included Chlorella sp., Chroomonas acuta Uterm., and Microcystis incerta Lemm.; the density of the phytoplankton ranged from to  cells/L with an average of  cells/L. However, Chlorophyta and Cyanophyta became the dominant phyla in summer, and the dominant species were Chlorella sp., Leptolyngbya valderiana Anagn., and Nephrocytium agardhianum Nageli.; the density of the phytoplankton varied from to  cells/L with an average of  cells/L. The density of the phytoplankton has increased significantly compared to the previous investigations in 2005. The index of Carlson nutritional status (TSIM) and the dominant genus assessment indicated that the majority of Baiyangdian Lake was in eutrophic state. Xing Wang, Yu Wang, Lusan Liu, Jianmin Shu, Yanzhong Zhu, and Juan Zhou Copyright © 2013 Xing Wang et al. All rights reserved. Evaluation of the Impacts of Land Use on Water Quality: A Case Study in The Chaohu Lake Basin Mon, 22 Jul 2013 11:55:04 +0000 http://www.hindawi.com/journals/tswj/2013/329187/ It has been widely accepted that there is a close relationship between the land use type and water quality. There have been some researches on this relationship from the perspective of the spatial configuration of land use in recent years. This study aims to analyze the influence of various land use types on the water quality within the Chaohu Lake Basin based on the water quality monitoring data and RS data from 2000 to 2008, with the small watershed as the basic unit of analysis. The results indicated that there was significant negative correlation between forest land and grassland and the water pollution, and the built-up area had negative impacts on the water quality, while the influence of the cultivated land on the water quality was very complex. Besides, the impacts of the landscape diversity on the indicators of water quality within the watershed were also analyzed, the result of which indicated there was a significant negative relationship between them. The results can provide important scientific reference for the local land use optimization and water pollution control and guidance for the formulation of policies to coordinate the exploitation and protection of the water resource. Juan Huang, Jinyan Zhan, Haiming Yan, Feng Wu, and Xiangzheng Deng Copyright © 2013 Juan Huang et al. All rights reserved. Installation of an Artificial Vegetating Island in Oligomesotrophic Lake Paro, Korea Mon, 15 Jul 2013 12:05:30 +0000 http://www.hindawi.com/journals/tswj/2013/857670/ After cut off of inflowing water, Lake Paro, an oligomesotrophic lake lost littoral zone, an important region for the aquatic ecosystem. For the first step of restoration, the artificial vegetation island was installed. The concentration of nutrients in lake water was not sufficient for the growth of macrophyte as total phosphate was ranged from 58 to 83 μg L−1. In order to overcome this problem, the hydrophobic substratum for bacterial attachment was selected as buoyant mat material of the artificial vegetation island. In this medium, total phosphate and total nitrogen were ranged from 190 to 1,060 μg L−1 and from 4.9 to 9.1 mg L−1, respectively. These concentrations were high enough for macrophytes growth. After launching 1,800 m2 of AVI in Lake Paro, the macrophytes, Iris pseudoacorus and Iris ensata, grew well after five years of launching without the addition of fertilizer. Furthermore, fishes were plentiful under the artificial vegetation island, and ducks were observed on the artificial vegetation island. Bacteria using sunlight as energy source and self-designed ecotechnology can be used as an alternative method for the restoration of disturbed littoral zone in oligo-mesotrophic lakes. Eun-Young Seo, Oh-Byung Kwon, Seung-Ik Choi, Ji-Ho Kim, and Tae-Seok Ahn Copyright © 2013 Eun-Young Seo et al. All rights reserved. Estimation Model of Soil Freeze-Thaw Erosion in Silingco Watershed Wetland of Northern Tibet Wed, 10 Jul 2013 12:07:02 +0000 http://www.hindawi.com/journals/tswj/2013/636521/ The freeze-thaw (FT) erosion is a type of soil erosion like water erosion and wind erosion. Limited by many factors, the grading evaluation of soil FT erosion quantities is not well studied. Based on the comprehensive analysis of the evaluation indices of soil FT erosion, we for the first time utilized the sensitivity of microwave remote sensing technology to soil moisture for identification of FT state. We established an estimation model suitable to evaluate the soil FT erosion quantity in Silingco watershed wetland of Northern Tibet using weighted summation method of six impact factors including the annual FT cycle days, average diurnal FT phase-changed water content, average annual precipitation, slope, aspect, and vegetation coverage. Finally, with the support of GIS, we classified soil FT erosion quantity in Silingco watershed wetland. The results showed that soil FT erosion are distributed in broad areas of Silingco watershed wetland. Different soil FT erosions with different intensities have evidently different spatial and geographical distributions. Bo Kong and Huan Yu Copyright © 2013 Bo Kong and Huan Yu. All rights reserved. Diurnal Characteristics of Ecosystem Respiration of Alpine Meadow on the Qinghai-Tibetan Plateau: Implications for Carbon Budget Estimation Mon, 24 Jun 2013 14:46:37 +0000 http://www.hindawi.com/journals/tswj/2013/289754/ Accurately estimating daily mean ecosystem respiration rate (Re) is important for understanding how ecosystem carbon budgets will respond to climate change. Usually, daily mean Re is represented by measurement using static chamber on alpine meadow ecosystems from 9:00 to 11:00 h a.m. local time directly. In the present study, however, we found that the calculated daily mean Re from 9:00 to 11:00 h a.m. local time was significantly higher than that from 0:00 to 23:30 h local time in an alpine meadow site, which might be caused by special climate condition on the Qinghai-Tibetan Plateau. Our results indicated that the calculated daily mean Re from 9:00 to 11:00 h a.m. local time cannot be used to represent daily mean Re directly. Yu Qin and Shuhua Yi Copyright © 2013 Yu Qin and Shuhua Yi. All rights reserved. Planktonic Rotifers in a Subtropical Shallow Lake: Succession, Relationship to Environmental Factors, and Use as Bioindicators Thu, 20 Jun 2013 08:30:42 +0000 http://www.hindawi.com/journals/tswj/2013/702942/ Changes in the density and species composition of planktonic rotifers as well as their relationship to several environmental variables were studied at Dadian Lake, a shallow subtropical lake, which was completely dredged and reconstructed. Samples were taken monthly (2006–2009) at five stations. The total rotifer abundance exponentially declined and reached a relatively stable stage in 2009. Polyarthra dolichoptera and Trichocerca pusilla dominated the rotifer community in most seasons. TN, TP, and went down at the beginning of the monitoring period, rebounded in the second winter, and then decreased and reached a stable state in 2009. CCA showed that the most significant variations were caused by fluctuations in temperature, , SRP, and NO2-N. The rotifer community experienced a two-stage succession and the difference of species between the stages was exhibited during warm seasons. GAMs indicated that the selected factors were responsible for 64.8% of the total rotifer abundance variance and 16.5~64.3% of the variances of individual species abundance. Most of the environmental parameters had effects on rotifer abundance that could only be described by complicated curves, characterised by unimodality and bimodality instead of linearity. Our study highlighted the temperature influence on rotifer species composition and total abundance in subtropical lakes. Gaohua Ji, Xianyun Wang, and Liqing Wang Copyright © 2013 Gaohua Ji et al. All rights reserved. A Review of Surface Water Quality Models Mon, 17 Jun 2013 17:03:58 +0000 http://www.hindawi.com/journals/tswj/2013/231768/ Surface water quality models can be useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body. The modeling results from these models under different pollution scenarios are very important components of environmental impact assessment and can provide a basis and technique support for environmental management agencies to make right decisions. Whether the model results are right or not can impact the reasonability and scientificity of the authorized construct projects and the availability of pollution control measures. We reviewed the development of surface water quality models at three stages and analyzed the suitability, precisions, and methods among different models. Standardization of water quality models can help environmental management agencies guarantee the consistency in application of water quality models for regulatory purposes. We concluded the status of standardization of these models in developed countries and put forward available measures for the standardization of these surface water quality models, especially in developing countries. Qinggai Wang, Shibei Li, Peng Jia, Changjun Qi, and Feng Ding Copyright © 2013 Qinggai Wang et al. All rights reserved. Effluents of Shrimp Farms and Its Influence on the Coastal Ecosystems of Bahía de Kino, Mexico Sun, 02 Jun 2013 08:47:00 +0000 http://www.hindawi.com/journals/tswj/2013/306370/ The impact on coastal ecosystems of suspended solids, organic matter, and bacteria in shrimp farm effluents is presented. Sites around Bahía de Kino were selected for comparative evaluation. Effluent entering Bahia Kino (1) enters Laguna La Cruz (2). A control site (3) was outside the influence of effluents. Water quality samples were collected every two weeks during the shrimp culture period. Our data show that the material load in shrimp farm effluents changes biogeochemical processes and aquatic health of the coastal ecosystem. Specifically, the suspended solids, particulate organic matter, chlorophyll a, viable heterotrophic bacteria, and Vibrio-like bacteria in the bay and lagoon were two- to three-fold higher than the control site. This can be mitigated by improvements in the management of aquaculture systems. Ramón H. Barraza-Guardado, José A. Arreola-Lizárraga, Marco A. López-Torres, Ramón Casillas-Hernández, Anselmo Miranda-Baeza, Francisco Magallón-Barrajas, and Cuauhtemoc Ibarra-Gámez Copyright © 2013 Ramón H. Barraza-Guardado et al. All rights reserved. Application of Scenario Analysis and Multiagent Technique in Land-Use Planning: A Case Study on Sanjiang Wetlands Thu, 30 May 2013 18:55:50 +0000 http://www.hindawi.com/journals/tswj/2013/219782/ Land-use planning has triggered debates on social and environmental values, in which two key questions will be faced: one is how to see different planning simulation results instantaneously and apply the results back to interactively assist planning work; the other is how to ensure that the planning simulation result is scientific and accurate. To answer these questions, the objective of this paper is to analyze whether and how a bridge can be built between qualitative and quantitative approaches for land-use planning work and to find out a way to overcome the gap that exists between the ability to construct computer simulation models to aid integrated land-use plan making and the demand for them by planning professionals. The study presented a theoretical framework of land-use planning based on scenario analysis (SA) method and multiagent system (MAS) simulation integration and selected freshwater wetlands in the Sanjiang Plain of China as a case study area. Study results showed that MAS simulation technique emphasizing quantitative process effectively compensated for the SA method emphasizing qualitative process, which realized the organic combination of qualitative and quantitative land-use planning work, and then provided a new idea and method for the land-use planning and sustainable managements of land resources. Huan Yu, Shi-Jun Ni, Bo Kong, Zheng-Wei He, Cheng-Jiang Zhang, Shu-Qing Zhang, Xin Pan, Chao-Xu Xia, and Xuan-Qiong Li Copyright © 2013 Huan Yu et al. All rights reserved. Summer Watering Patterns of Mule Deer in the Great Basin Desert, USA: Implications of Differential Use by Individuals and the Sexes for Management of Water Resources Wed, 17 Oct 2012 09:49:45 +0000 http://www.hindawi.com/journals/tswj/2012/846218/ Changes in the abundance and distribution of free water can negatively influence wildlife in arid regions. Free water is considered a limiting factor for mule deer (Odocoileus hemionus) in the Great Basin Desert. Consequently, a better understanding of differential use of water by individuals and the sexes could influence the conservation and management of mule deer and water resources in their habitats. We deployed remote cameras at all known water sources (13 wildlife water developments and 4 springs) on one mountain range in western Utah, USA, during summer from 2007 to 2011 to document frequency and timing of water use, number of water sources used by males and females, and to estimate population size from individually identified mule deer. Male and female mule deer used different water sources but visited that resource at similar frequencies. Individual mule deer used few water sources and exhibited high fidelity to that resource. Wildlife water developments were frequently used by both sexes. Our results highlight the differing use of water sources by sexes and individual mule deer. This information will help guide managers when siting and reprovisioning wildlife water developments meant to benefit mule deer and will contribute to the conservation and management of this species. Andrew V. Shields, Randy T. Larsen, and Jericho C. Whiting Copyright © 2012 Andrew V. Shields et al. All rights reserved. Geographical Gradients in Argentinean Terrestrial Mammal Species Richness and Their Environmental Correlates Mon, 17 Sep 2012 12:40:27 +0000 http://www.hindawi.com/journals/tswj/2012/819328/ We analysed the main geographical trends of terrestrial mammal species richness (SR) in Argentina, assessing how broad-scale environmental variation (defined by climatic and topographic variables) and the spatial form of the country (defined by spatial filters based on spatial eigenvector mapping (SEVM)) influence the kinds and the numbers of mammal species along these geographical trends. We also evaluated if there are pure geographical trends not accounted for by the environmental or spatial factors. The environmental variables and spatial filters that simultaneously correlated with the geographical variables and SR were considered potential causes of the geographic trends. We performed partial correlations between SR and the geographical variables, maintaining the selected explanatory variables statistically constant, to determine if SR was fully explained by them or if a significant residual geographic pattern remained. All groups and subgroups presented a latitudinal gradient not attributable to the spatial form of the country. Most of these trends were not explained by climate. We used a variation partitioning procedure to quantify the pure geographic trend (PGT) that remained unaccounted for. The PGT was larger for latitudinal than for longitudinal gradients. This suggests that historical or purely geographical causes may also be relevant drivers of these geographical gradients in mammal diversity. Ana L. Márquez, Raimundo Real, Marta S. Kin, José Carlos Guerrero, Betina Galván, A. Márcia Barbosa, Jesús Olivero, L. Javier Palomo, J. Mario Vargas, and Enrique Justo Copyright © 2012 Ana L. Márquez et al. All rights reserved. Caatinga Revisited: Ecology and Conservation of an Important Seasonal Dry Forest Wed, 01 Aug 2012 09:19:38 +0000 http://www.hindawi.com/journals/tswj/2012/205182/ Besides its extreme climate conditions, the Caatinga (a type of tropical seasonal forest) hosts an impressive faunal and floristic biodiversity. In the last 50 years there has been a considerable increase in the number of studies in the area. Here we aimed to present a review of these studies, focusing on four main fields: vertebrate ecology, plant ecology, human ecology, and ethnobiology. Furthermore, we identify directions for future research. We hope that the present paper will help defining actions and strategies for the conservation of the biological diversity of the Caatinga. Ulysses Paulino de Albuquerque, Elcida de Lima Araújo, Ana Carla Asfora El-Deir, André Luiz Alves de Lima, Antonio Souto, Bruna Martins Bezerra, Elba Maria Nogueira Ferraz, Eliza Maria Xavier Freire, Everardo Valadares de Sá Barreto Sampaio, Flor Maria Guedes Las-Casas, Geraldo Jorge Barbosa de Moura, Glauco Alves Pereira, Joabe Gomes de Melo, Marcelo Alves Ramos, Maria Jesus Nogueira Rodal, Nicola Schiel, Rachel Maria de Lyra-Neves, Rômulo Romeu Nóbrega Alves, Severino Mendes de Azevedo-Júnior, Wallace Rodrigues Telino Júnior, and William Severi Copyright © 2012 Ulysses Paulino de Albuquerque et al. All rights reserved. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone Mon, 04 Jun 2012 15:40:33 +0000 http://www.hindawi.com/journals/tswj/2012/705872/ We explored ability of reflectance vegetation indexes (VIs) related to chlorophyll fluorescence emission (𝑅686/𝑅630, 𝑅740/𝑅800) and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as (𝑅531−𝑅570)/(𝑅531−𝑅570)) to track changes in the CO2 assimilation rate and Light Use Efficiency (LUE) in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO2 assimilation (𝐴MAX) was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ(𝑅686/𝑅630) of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to 𝐴MAX (𝑅2=0.51). In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP), Net Ecosystem Exchange (NEE), and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index 𝑅686/𝑅630 with NEE and GPP. Alexander Ač, Zbyněk Malenovský, Otmar Urban, Jan Hanuš, Martina Zitová, Martin Navrátil, Martina Vráblová, Julie Olejníčková, Vladimír Špunda, and Michal Marek Copyright © 2012 Alexander Ač et al. All rights reserved. Patterns of Diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean Region Tue, 22 May 2012 15:32:02 +0000 http://www.hindawi.com/journals/tswj/2012/164890/ The geographical distribution of the Rissoidae in the Atlantic Ocean and Mediterranean Sea was compiled and is up-to-date until July 2011. All species were classified according to their mode of larval development (planktotrophic and nonplanktotrophic), and bathymetrical zonation (shallow species—those living between the intertidal and 50 m depth, and deep species—those usually living below 50 m depth). 542 species of Rissoidae are presently reported to the Atlantic Ocean and the Mediterranean Sea, belonging to 33 genera. The Mediterranean Sea is the most diverse site, followed by Canary Islands, Caribbean, Portugal, and Cape Verde. The Mediterranean and Cape Verde Islands are the sites with higher numbers of endemic species, with predominance of Alvania spp. in the first site, and of Alvania and Schwartziella at Cape Verde. In spite of the large number of rissoids at Madeira archipelago, a large number of species are shared with Canaries, Selvagens, and the Azores, thus only about 8% are endemic to the Madeira archipelago. Most of the 542-rissoid species that live in the Atlantic and in the Mediterranean are shallow species (323), 110 are considered as deep species, and 23 species are reported in both shallow and deep waters. There is a predominance of nonplanktotrophs in islands, seamounts, and at high and medium latitudes. This pattern is particularly evident in the genera Crisilla, Manzonia, Onoba, Porosalvania, Schwartziella, and Setia. Planktotrophic species are more abundant in the eastern Atlantic and in the Mediterranean Sea. The results of the analysis of the probable directions of faunal flows support the patterns found by both the Parsimony Analysis of Endemicity and the geographical distribution. Four main source areas for rissoids emerge: Mediterranean, Caribbean, Canaries/Madeira archipelagos, and the Cape Verde archipelago. We must stress the high percentage of endemics that occurs in the isolated islands of Saint Helena, Tristan da Cunha, Cape Verde archipelago and also the Azores, thus reinforcing the legislative protective actions that the local governments have implemented in these islands during the recent years. Sérgio P. Ávila, Jeroen Goud, and António M. de Frias Martins Copyright © 2012 Sérgio P. Ávila et al. All rights reserved. Two Rare Northern Entoloma Species Observed in Sicily under Exceptionally Cold Weather Conditions Thu, 03 May 2012 08:57:23 +0000 http://www.hindawi.com/journals/tswj/2012/957212/ The biology and ecology of many Entoloma species is still poorly known as well as their geographical distribution. In Italy, there are no studies on the influence of weather on fungal abundance and richness and our knowledge on the ecology and distribution of Entoloma species needs to be improved. The discovery of two Entoloma species in Sicily (southern Italy), reported in the literature as belonging to the habitat of north European countries, was the basis leading to the assumption that anomalous climatic conditions could stimulate the growth of northern entolomas in the southernmost Mediterranean regions. The results of this study show that the presence of northern Entoloma species in Sicily is not influenced by the Mediterranean type of vegetation, by edaphic or altitudinal factors but by anomalous climatic trends of precipitations and temperatures which stimulate the fructification of basidiomata in correspondence with a thermal shock during autumn. Giuseppe Venturella, Alessandro Saitta, Gerlando Mandracchia, and Maria Letizia Gargano Copyright © 2012 Giuseppe Venturella et al. All rights reserved. Reducing Greenhouse Gas Emissions in Grassland Ecosystems of the Central Lithuania: Multi-Criteria Evaluation on a Basis of the ARAS Method Thu, 03 May 2012 08:36:03 +0000 http://www.hindawi.com/journals/tswj/2012/908384/ N2O, CH4, and CO2 are potential greenhouse gas (GHG) contributing to climate change; therefore, solutions have to be sought to reduce their emission from agriculture. This work evaluates GHG emission from grasslands submitted to different mineral fertilizers during vegetation period (June–September) in two experimental sites, namely, seminatural grassland (8 treatments of mineral fertilizers) and cultural pasture (intensively managed) in the Training Farm of the Lithuanian University of Agriculture. Chamber method was applied for evaluation of GHG emissions on the field scale. As a result, soil chemical composition, compactness, temperature, and gravimetric moisture as well as biomass yield of fresh and dry biomass and botanical composition, were assessed during the research. Furthermore, a simulation of multi-criteria assessment of sustainable fertilizers management was carried out on a basis of ARAS method. The multicriteria analysis of different fertilizing regimes was based on a system of environmental and productivity indices. Consequently, agroecosystems of cultural pasture (N180P120K150) and seminatural grassland fertilizing rates N180P120K150 and N60P40K50 were evaluated as the most sustainable alternatives leading to reduction of emissions between biosphere-atmosphere and human-induced biogenic pollution in grassland ecosystems, thus contributing to improvement of countryside environment. Ligita Balezentiene and Albinas Kusta Copyright © 2012 Ligita Balezentiene and Albinas Kusta. All rights reserved. Reproductive Ecology of Prochilodus brevis an Endemic Fish from the Semiarid Region of Brazil Thu, 03 May 2012 07:58:53 +0000 http://www.hindawi.com/journals/tswj/2012/810532/ The commercially important migratory fish Prochilodus brevis is from the Neotropical region, and understanding the reproductive ecology of this potamodromous fish is essential for its conservation and management. This study investigated the length-mass relationship, sex ratio, length at first gonadal maturity, gonadal development stages, gonadosomatic index, condition factor, and reproductive period of P. brevis. Temporal distribution of rainfall, temperature, dissolved oxygen concentration, pH, and electrical conductivity of the water were related to the reproductive period of this fish. Rainfall seems to be the main environmental factor which modulates changes in limnological parameters and the timing of the spawning period of this fish. P. brevis migrates into lower reaches of the river to feed during the dry season and returns to the upper reaches during the rainy season to spawn. Inadequate facilities for migration create obstacles for spawning success of this ecologically important fish. Liliane de Lima Gurgel, José Roberto Verani, and Sathyabama Chellappa Copyright © 2012 Liliane de Lima Gurgel et al. All rights reserved. Siderophore-Producing Bacteria from a Sand Dune Ecosystem and the Effect of Sodium Benzoate on Siderophore Production by a Potential Isolate Wed, 02 May 2012 15:20:38 +0000 http://www.hindawi.com/journals/tswj/2012/857249/ Bioremediation in natural ecosystems is dependent upon the availability of micronutrients and cofactors, of which iron is one of the essential elements. Under aerobic and alkaline conditions, iron oxidizes to Fe+3 creating iron deficiency. To acquire this essential growth-limiting nutrient, bacteria produce low-molecular-weight, high-affinity iron chelators termed siderophores. In this study, siderophore-producing bacteria from rhizosphere and nonrhizosphere areas of coastal sand dunes were isolated using a culture-dependent approach and were assigned to 8 different genera with the predominance of Bacillus sp. Studies on the ability of these isolates to grow on sodium benzoate revealed that a pigmented bacterial culture TMR2.13 identified as Pseudomonas aeruginosa showed growth on mineral salts medium (MSM) with 2% of sodium benzoate and produced a yellowish fluorescent siderophore identified as pyoverdine. This was inhibited above 54 μM of added iron in MSM with glucose without affecting growth, while, in presence of sodium benzoate, siderophore was produced even up to the presence of 108 μM of added iron. Increase in the requirement of iron for metabolism of aromatic compounds in ecosystems where the nutrient deficiencies occur naturally would be one of the regulating factors for the bioremediation process. Teja Gaonkar, Pramoda Kumar Nayak, Sandeep Garg, and Saroj Bhosle Copyright © 2012 Teja Gaonkar et al. All rights reserved. Interannual Variation in Root Production in Grasslands Affected by Artificially Modified Amount of Rainfall Wed, 02 May 2012 14:58:41 +0000 http://www.hindawi.com/journals/tswj/2012/805298/ The effect of different amounts of rainfall on the below-ground plant biomass was studied in three grassland ecosystems. Responses of the lowland (dry Festuca grassland), highland (wet Cirsium grassland), and mountain (Nardus grassland) grasslands were studied during five years (2006–2010). A field experiment based on rainout shelters and gravity irrigation simulated three climate scenarios: rainfall reduced by 50% (dry), rainfall increased by 50% (wet), and the natural rainfall of the current growing season (ambient). The interannual variation in root increment and total below-ground biomass reflected the experimentally manipulated amount of precipitation and also the amount of current rainfall of individual years. The effect of year on these below-ground parameters was found significant in all studied grasslands. In comparison with dry Festuca grassland, better adapted to drought, submontane wet Cirsium grassland was more sensitive to the different water inputs forming rather lower amount of below-ground plant matter at reduced precipitation. Karel Fiala, Ivan Tůma, and Petr Holub Copyright © 2012 Karel Fiala et al. All rights reserved. Applying Fuzzy Logic to Comparative Distribution Modelling: A Case Study with Two Sympatric Amphibians Wed, 02 May 2012 10:27:42 +0000 http://www.hindawi.com/journals/tswj/2012/428206/ We modelled the distributions of two toads (Bufo bufo and Epidalea calamita) in the Iberian Peninsula using the favourability function, which makes predictions directly comparable for different species and allows fuzzy logic operations to relate different models. The fuzzy intersection between individual models, representing favourability for the presence of both species simultaneously, was compared with another favourability model built on the presences shared by both species. The fuzzy union between individual models, representing favourability for the presence of any of the two species, was compared with another favourability model based on the presences of either or both of them. The fuzzy intersections between favourability for each species and the complementary of favourability for the other (corresponding to the logical operation “A and not B”) were compared with models of exclusive presence of one species versus the exclusive presence of the other. The results of modelling combined species data were highly similar to those of fuzzy logic operations between individual models, proving fuzzy logic and the favourability function valuable for comparative distribution modelling. We highlight several advantages of fuzzy logic over other forms of combining distribution models, including the possibility to combine multiple species models for management and conservation planning. A. Márcia Barbosa and Raimundo Real Copyright © 2012 A. Márcia Barbosa and Raimundo Real. All rights reserved. The Use of Geostatistics in the Study of Floral Phenology of Vulpia geniculata (L.) Link Tue, 01 May 2012 19:02:45 +0000 http://www.hindawi.com/journals/tswj/2012/624247/ Traditionally phenology studies have been focused on changes through time, but there exist many instances in ecological research where it is necessary to interpolate among spatially stratified samples. The combined use of Geographical Information Systems (GIS) and Geostatistics can be an essential tool for spatial analysis in phenological studies. Geostatistics are a family of statistics that describe correlations through space/time and they can be used for both quantifying spatial correlation and interpolating unsampled points. In the present work, estimations based upon Geostatistics and GIS mapping have enabled the construction of spatial models that reflect phenological evolution of Vulpia geniculata (L.) Link throughout the study area during sampling season. Ten sampling points, scattered troughout the city and low mountains in the “Sierra de Córdoba” were chosen to carry out the weekly phenological monitoring during flowering season. The phenological data were interpolated by applying the traditional geostatitical method of Kriging, which was used to ellaborate weekly estimations of V. geniculata phenology in unsampled areas. Finally, the application of Geostatistics and GIS to create phenological maps could be an essential complement in pollen aerobiological studies, given the increased interest in obtaining automatic aerobiological forecasting maps. Eduardo J. León Ruiz, Herminia García Mozo, Eugenio Domínguez Vilches, and Carmen Galán Copyright © 2012 Eduardo J. León Ruiz et al. All rights reserved. Rodent Damage to Natural and Replanted Mountain Forest Regeneration Tue, 01 May 2012 16:08:44 +0000 http://www.hindawi.com/journals/tswj/2012/872536/ Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (𝜒2=44.04, 𝑃<0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (𝜒2=55.89, 𝑃<0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings. Marta Heroldová, Josef Bryja, Eva Jánová, Josef Suchomel, and Miloslav Homolka Copyright © 2012 Marta Heroldová et al. All rights reserved. An Evaluation of Leaf Biomass : Length Ratio as a Tool for Nondestructive Assessment in Eelgrass (Zostera marina L.) Tue, 01 May 2012 15:53:35 +0000 http://www.hindawi.com/journals/tswj/2012/543730/ The characterization of biomass and its dynamics provides valuable information for the assessment of natural and transplanted eelgrass populations. The need for simple, nondestructive assessments has led to the use of the leaf biomass-to-length ratio for converting leaf-length measurements, which can be easily obtained, to leaf growth rates through the plastochrone method. Using data on leaf biomass and length collected in three natural eelgrass populations and a mesocosm, we evaluated the suitability of a leaf weight-to-length ratio for nondestructive assessments. For the data sets considered, the isometric scaling that sustains the weight-to-length proxy always produced inconsistent fittings, and for leaf-lengths greater than a threshold value, the conversion of leaf length to biomass generated biased estimations. In contrast, an allometric scaling of leaf biomass and length was highly consistent in all the cases considered. And these nondestructive assessments generated reliable levels of reproducibility in leaf biomass for all the ranges of variability in leaf lengths. We argue that the use of allometric scaling for the representation of leaf biomass in terms of length provides a more reliable approach for estimating eelgrass biomass. Hector Echavarria-Heras, Elena Solana-Arellano, Kun-Seop Lee, Shinya Hosokawa, and Ernesto Franco-Vizcaíno Copyright © 2012 Hector Echavarria-Heras et al. All rights reserved. Shesher and Welala Floodplain Wetlands (Lake Tana, Ethiopia): Are They Important Breeding Habitats for Clarias gariepinus and the Migratory Labeobarbus Fish Species? Mon, 30 Apr 2012 11:46:10 +0000 http://www.hindawi.com/journals/tswj/2012/298742/ This study aims at investigating the spawning migration of the endemic Labeobarbus species and C. gariepinus from Lake Tana, through Ribb River, to Welala and Shesher wetlands. The study was conducted during peak spawning months (July to October, 2010). Fish were collected through overnight gillnet settings. A total of 1725 specimens of the genus Labeobarbus (13 species) and 506 specimens of C. gariepinus were collected. Six species of Labeobarbus formed prespawning aggregation at Ribb River mouth. However, no Labeobarbus species was found to spawn in the two wetlands. More than 90% of the catch in Welala and Shesher wetlands was contributed by C. gariepinus. This implies that these wetlands are ideal spawning and nursery habitats for C. gariepinus but not for the endemic Labeobarbus species. Except L. intermedius, all the six Labeobarbus species (aggregated at Ribb River mouth) and C. gariepinus (spawning at Shesher and Welala wetlands) were temporally segregated. Wassie Anteneh, Eshete Dejen, and Abebe Getahun Copyright © 2012 Wassie Anteneh et al. All rights reserved. World Aquaculture: Environmental Impacts and Troubleshooting Alternatives Sun, 29 Apr 2012 10:47:05 +0000 http://www.hindawi.com/journals/tswj/2012/389623/ Aquaculture has been considered as an option to cope with the world food demand. However, criticisms have arisen around aquaculture, most of them related to the destruction of ecosystems such as mangrove forest to construct aquaculture farms, as well as the environmental impacts of the effluents on the receiving ecosystems. The inherent benefits of aquaculture such as massive food production and economical profits have led the scientific community to seek for diverse strategies to minimize the negative impacts, rather than just prohibiting the activity. Aquaculture is a possible panacea, but at present is also responsible for diverse problems related with the environmental health; however the new strategies proposed during the last decade have proven that it is possible to achieve a sustainable aquaculture, but such strategies should be supported and proclaimed by the different federal environmental agencies from all countries. Additionally there is an urgent need to improve legislation and regulation for aquaculture. Only under such scenario, aquaculture will be a sustainable practice. Marcel Martinez-Porchas and Luis R. Martinez-Cordova Copyright © 2012 Marcel Martinez-Porchas and Luis R. Martinez-Cordova. All rights reserved. Quantitative Analysis of Driving Factors of Grassland Degradation: A Case Study in Xilin River Basin, Inner Mongolia Tue, 24 Apr 2012 12:58:34 +0000 http://www.hindawi.com/journals/tswj/2012/169724/ Current literature suggests that grassland degradation occurs in areas with poor soil conditions or noticeable environmental changes and is often a result of overgrazing or human disturbances. However, these views are questioned in our analyses. Based on the analysis of satellite vegetation maps from 1984, 1998, and 2004 for the Xilin River Basin, Inner Mongolia, China, and binary logistic regression (BLR) analysis, we observe the following: (1) grassland degradation is positively correlated with the growth density of climax communities; (2) our findings do not support a common notion that a decrease of biological productivity is a direct indicator of grassland degradation; (3) a causal relationship between grazing intensity and grassland degradation was not found; (4) degradation severity increased steadily towards roads but showed different trends near human settlements. This study found complex relationships between vegetation degradation and various microhabitat conditions, for example, elevation, slope, aspect, and proximity to water. Yichun Xie and Zongyao Sha Copyright © 2012 Yichun Xie and Zongyao Sha. All rights reserved. Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata Tue, 24 Apr 2012 11:39:46 +0000 http://www.hindawi.com/journals/tswj/2012/125785/ Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50 values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L−1, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50 values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals. M. Shuhaimi-Othman, R. Nur-Amalina, and Y. Nadzifah Copyright © 2012 M. Shuhaimi-Othman et al. All rights reserved. Diet Composition and Feeding Strategies of the Stone Marten (Martes foina) in a Typical Mediterranean Ecosystem Tue, 24 Apr 2012 08:31:23 +0000 http://www.hindawi.com/journals/tswj/2012/163920/ Stone martens (Martes foina) are documented as generalist throughout their distributional range whose diet composition is affected by food availability. We tested if this occurs and what feeding strategies it follows in a typical Mediterranean ecosystem in Central Greece by analysing contents from 106 stomachs, seasonally collected from three different habitats during 2003–2006. Seasonal variation in diet and feeding strategies was evident and linked to seasonal nutritional requirements, but possibly imposed by strong interference competition and intraguild predation. Fleshy fruits and arthropods predominated in the diet, but also mammals and birds were frequently consumed. An overall low dietary niche breadth (𝐵A=0.128) indicated a fruit specialization tendency. A generalised diet occurred in spring with high individual specialisation, whereas more animal-type prey was consumed than fruits. A population specialization towards fruits was indicated during summer and autumn, whereas insects were consumed occasionally by males. In those seasons it switched to more clumped food types such as fruits and insects. In winter it selectively exploited both adult and larvae insects and partially fruits overwinter on plants. The tendency to consume particular prey items seasonally reflected both the population specialist behaviour and the individual flexibility preyed on different food resources. Dimitrios E. Bakaloudis, Christos G. Vlachos, Malamati A. Papakosta, Vasileios A. Bontzorlos, and Evangelos N. Chatzinikos Copyright © 2012 Dimitrios E. Bakaloudis et al. All rights reserved. Water Hyacinth Eichhornia crassipes (Mart.) Solms-Laubach Dynamics and Succession in the Nyanza Gulf of Lake Victoria (East Africa): Implications for Water Quality and Biodiversity Conservation Thu, 19 Apr 2012 14:58:44 +0000 http://www.hindawi.com/journals/tswj/2012/106429/ This study, conducted in Nyanza Gulf of Lake Victoria, assessed ecological succession and dynamic status of water hyacinth. Results show that water hyacinth is the genesis of macrophyte succession. On establishment, water hyacinth mats are first invaded by native emergent macrophytes, Ipomoea aquatica Forsk., and Enydra fluctuans Lour., during early stages of succession. This is followed by hippo grass Vossia cuspidata (Roxb.) Griff. in mid- and late stages whose population peaks during climax stages of succession with concomitant decrease in water hyacinth biomass. Hippo grass depends on water hyacinth for buoyancy, anchorage, and nutrients. The study concludes that macrophyte succession alters aquatic biodiversity and that, since water hyacinth infestation and attendant succession are a symptom of broader watershed management and pollution problems, aquatic macrophyte control should include reduction of nutrient loads and implementing multifaceted approach that incorporates biological agents, mechanical/manual control with utilization of harvested weed for cottage industry by local communities. John Gichuki, Reuben Omondi, Priscillar Boera, Tom Okorut, Ally Said Matano, Tsuma Jembe, and Ayub Ofulla Copyright © 2012 John Gichuki et al. All rights reserved. Modeling Rare Species Distribution at the Edge: The Case for the Vulnerable Endemic Pyrenean Desman in France Thu, 19 Apr 2012 13:47:33 +0000 http://www.hindawi.com/journals/tswj/2012/612965/ The endemic Pyrenean Desman (Galemys pyrenaicus) is an elusive, rare, and vulnerable species declining over its entire and narrow range (Spain, Portugal, France, and Andorra). The principal set of conservation measures in France is a 5-years National Action Plan based on 25 conservation actions. Priority is given to update its present distribution and develop tools for predictive distribution models. We aim at building the first species distribution model and map for the northern edge of the range of the Desman and confronting the outputs of the model to target conservation efforts in the context of environmental change. Contrasting to former comparable studies, we derive a simpler model emphasizing the importance of factors linked to precipitation and not to the temperature. If temperature is one of the climate change key factors, depicted shrinkage in Desman distribution could be lower or null at the northern (French) edge suggesting thus a major role for this northern population in terms of conservation of the species. Finally, we question the applied issue of temporal and spatial transferability for such environmental favourability models when it is made at the edge of the distribution range. M. Williams-Tripp, F. J. N. D'Amico, C. Pagé, A. Bertrand, M. Némoz, and J. A. Brown Copyright © 2012 M. Williams-Tripp et al. All rights reserved. An Investigation into Occasional White Spot Syndrome Virus Outbreak in Traditional Paddy Cum Prawn Fields in India Thu, 19 Apr 2012 13:40:12 +0000 http://www.hindawi.com/journals/tswj/2012/340830/ A yearlong (September 2009–August 2010) study was undertaken to find out possible reasons for occasional occurrence of White Spot Syndrome Virus (WSSV) outbreak in the traditional prawn farms adjoining Cochin backwaters. Physicochemical and bacteriological parameters of water and sediment from feeder canal and four shrimp farms were monitored on a fortnightly basis. The physicochemical parameters showed variation during the two production cycles and between the farms studied. Dissolved oxygen (DO) content of water from feeder canal showed low oxygen levels (as low as 0.8 mg/L) throughout the study period. There was no disease outbreak in the perennial ponds. Poor water exchange coupled with nutrient loading from adjacent houses resulted in phytoplankton bloom in shallow seasonal ponds which led to hypoxic conditions in early morning and supersaturation of DO in the afternoon besides considerably high alkaline pH. Ammonia levels were found to be very high in these ponds. WSSV outbreak was encountered twice during the study leading to mass mortalities in the seasonal ponds. The hypoxia and high ammonia content in water and abrupt fluctuations in temperature, salinity and pH might lead to considerable stress in the shrimps triggering WSSV infection in these traditional ponds. Deborah Gnana Selvam, K. M. Mujeeb Rahiman, and A. A. Mohamed Hatha Copyright © 2012 Deborah Gnana Selvam et al. All rights reserved. The Effects of Environment and Physiological Cyclicity on the Immune System of Viperinae Sun, 01 Apr 2012 09:37:35 +0000 http://www.hindawi.com/journals/tswj/2012/574867/ One of the important aspects of species’ survival is connected with global climate changes, which also conditions the epidemiology of infectious diseases. Poikilotherms are exposed, as other species, to climatic influence, especially due to their physiological peculiarities such as important stages of their life cycle: hibernation, shedding, and active phase. The immune system serves as an accurate indicator of the health status and stress levels in these species. This study aimed to monitor the changes of innate (leukocyte subpopulations and total immune globulins) and adaptive immunity (in vitro leukocyte blast transformation) of two viper species, V. berus berus and V. ammodytes ammodytes, endemic in Europe and spread in different regions of Romania during their three major life cycles, hibernation, shedding, and active phase. The results indicated that seasonal variance and cycle rather than species and regional distribution influence the functionality of the immune system. Lorand Kobolkuti, Daniel Cadar, Gabor Czirjak, Mihaela Niculae, Timea Kiss, Carmen Sandru, and Marina Spinu Copyright © 2012 Lorand Kobolkuti et al. All rights reserved. Diversity of Woodland Communities and Plant Species along an Altitudinal Gradient in the Guancen Mountains, China Sun, 01 Apr 2012 09:26:37 +0000 http://www.hindawi.com/journals/tswj/2012/398765/ Study on plant diversity is the base of woodland conservation. The Guancen Mountains are the northern end of Luliang mountain range in North China. Fifty-three quadrats of 10m×20m of woodland communities were randomly established along an altitudinal gradient. Data for species composition and environmental variables were measured and recorded in each quadrat. To investigate the variation of woodland communities, a Two-Way Indicator Species Analysis (TWINSPAN) and a Canonical Correspondence Analysis (CCA) were conducted, while species diversity indices were used to analyse the relationships between species diversity and environmental variables in this study. The results showed that there were eight communities of woodland vegetation; each of them had their own characteristics in composition, structure, and environment. The variation of woodland communities was significantly related to elevation and also related to slope, slope aspect, and litter thickness. The cumulative percentage variance of species-environment relation for the first three CCA axes was 93.5%. Elevation was revealed as the factor which most influenced community distribution and species diversity. Species diversity was negatively correlated with elevation, slope aspect, and litter thickness, but positively with slope. Species richness and heterogeneity increased first and then decreased but evenness decreased significantly with increasing elevation. Species diversity was correlated with slope, slope aspect, and litter thickness. Dongping Meng, Jin-Tun Zhang, and Min Li Copyright © 2012 Dongping Meng et al. All rights reserved. N : P Stoichiometry in a Forested Runoff during Storm Events: Comparisons with Regions and Vegetation Types Sun, 01 Apr 2012 08:32:06 +0000 http://www.hindawi.com/journals/tswj/2012/257392/ Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo. Lanlan Guo, Yi Chen, Zhao Zhang, and Takehiko Fukushima Copyright © 2012 Lanlan Guo et al. All rights reserved. Ranging Patterns of Critically Endangered Colobine, Presbytis chrysomelas chrysomelas Mon, 12 Mar 2012 14:56:44 +0000 http://www.hindawi.com/journals/tswj/2012/594382/ Presbytis chrysomelas chrysomelas endemic only in Sarawak and Kalimantan was categorized by IUCN as a critically endangered primate that require special attention from research and conservation perspectives. A qualitative study on ranging patterns of P. c. chrysomelas was conducted in the Samunsam Wildlife Sanctuary, Sarawak. The study was conducted over a period of 13 months from December 2004 to December 2005 with 213 days of observation. Behavioural observation covered 17 groups with special emphasis on two main groups and 1 subadult group. Scanning and focal sampling were employed as the observation methods. Results indicated that P. c. chrysomelas had vertical, straight horizontal, and cross-horizontal types of movement patterns. P. c. chrysomelas was recorded to have a short movement distance (31.8–54.3 m). Distribution, abundance types, and food resources might be the factors that shaped the patterns of movement and distance in P. c. chrysomelas. Ahmad Ampeng and Badrul Munir Md-Zain Copyright © 2012 Ahmad Ampeng and Badrul Munir Md-Zain. All rights reserved. A Refined Methodology for Defining Plant Communities Using Postagricultural Data from the Neotropics Mon, 12 Mar 2012 13:19:17 +0000 http://www.hindawi.com/journals/tswj/2012/365409/ How best to define and quantify plant communities was investigated using long-term plot data sampled from a recovering pasture in Puerto Rico and abandoned sugarcane and banana plantations in Ecuador. Significant positive associations between pairs of old field species were first computed and then clustered together into larger and larger species groups. I found that (1) no pasture or plantation had more than 5% of the possible significant positive associations, (2) clustering metrics showed groups of species participating in similar clusters among the five pasture/plantations over a gradient of decreasing association strength, and (3) there was evidence for repeatable communities—especially after banana cultivation—suggesting that past crops not only persist after abandonment but also form significant associations with invading plants. I then showed how the clustering hierarchy could be used to decide if any two pasture/plantation plots were in the same community, that is, to define old field communities. Finally, I suggested a similar procedure could be used for any plant community where the mechanisms and tolerances of species form the “cohesion” that produces clustering, making plant communities different than random assemblages of species. Randall W. Myster Copyright © 2012 Randall W. Myster. All rights reserved. Biomass Estimation of Dry Tropical Woody Species at Juvenile Stage Wed, 15 Feb 2012 12:38:27 +0000 http://www.hindawi.com/journals/tswj/2012/790219/ Accurate characterization of biomass in different forest components is important to estimate their contribution to total carbon stock. Due to lack of allometric equations for biomass estimation of woody species at juvenile stage, the carbon stored in this forest component is ignored. We harvested 47 woody species at juvenile stage in a dry tropical forest and developed regression models for the estimation of above-ground biomass (AGB). The models including wood-specific gravity (𝜌) exhibited higher 𝑅2 than those without 𝜌. The model consisting of 𝜌, stem diameter (𝐷), and height (𝐻) not only exhibited the highest 𝑅2 value but also had the lowest standard error of estimate. We suggest that 𝜌-based regression model is a viable option for nondestructive estimation of biomass of forest trees at juvenile stage. R. K. Chaturvedi, A. S. Raghubanshi, and J. S. Singh Copyright © 2011 R. K. Chaturvedi et al. All rights reserved. Rapid and High Seed Germination and Large Soil Seed Bank of Senecio aquaticus in Managed Grassland Wed, 04 Jan 2012 10:57:39 +0000 http://www.hindawi.com/journals/tswj/2012/723808/ Senecio aquaticus, regionally a Red List species in Europe, has become increasingly abundant in agricultural grassland of medium to high management intensity in Switzerland, Southern Germany, and Austria in recent years, where it is a threat for animal and human health due to its toxicity. In this study, we investigated the seed ecology of S. aquaticus to help protection of the species in relic populations while improving its control when abundant in managed grassland. Germination percentages of fresh ripe seeds of S. aquaticus were on average 68% in 2008, but only 45% in 2010, indicating yearly variation. Germination was generally fast: ten days after the onset of the tests, often more than 45% of all seeds had germinated. When covered with a soil layer of 5 mm, germination was only 16% compared to 63% in full light. Seeds buried in the soil for one and two years showed a germination of 78%, significantly higher than that of fresh ripe seeds, thus suggesting a stimulating effect of cold-wet stratification on germination and long seed survival in the soil. In grasslands with established populations of S. aquaticus, the number of germinable seeds of the species ranged from 361 to 1875 m-2 in topsoil (0–10 cm) with an average of 1139 m-2. The large seed bank and the rapid and high germination of S. aquaticus suggest that allowing seed formation is important for its preservation in relic populations. With respect to agricultural grassland, strategies to control the species should initially target hindering seed production and dispersal. Matthias Suter and Andreas Lüscher Copyright © 2012 Matthias Suter and Andreas Lüscher. All rights reserved. Alternative Attractors of Shallow Lakes Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/731862/abs/ Ponds and shallow lakes can be very clear with abundant submerged plants, or very turbid due to a high concentration of phytoplankton and suspended sediment particles. These strongly contrasting ecosystem states have been found to represent alternative attractors with distinct stabilizing feedback mechanisms. In the turbid state, the development of submerged vegetation is prevented by low underwater light levels. The unprotected sediment frequently is resuspended by wave action and by fish searching for food causing a further decrease of transparency. Since there are no plants that could serve as refuges, zooplankton is grazed down by fish to densities insufficient to control algal blooms. In contrast, the clear state in eutrophic shallow lakes is dominated by aquatic macrophytes. The submerged macrophytes prevent sediment resuspension, take up nutrients from the water, and provide a refuge for zooplankton against fish predation. These processes buffer the impacts of increased nutrient loads until they become too high. Consequently, the response of shallow lakes to eutrophication tends to be catastrophic rather than smooth, and various lakes switch back and forth abruptly between a clear and a turbid state repeatedly without obvious external forcing. Importantly, a switch from a turbid to a stable clear state often can be invoked by means of biomanipulation in the form of a temporary reduction of the fish stock. Marten Scheffer Copyright © 2001 Marten Scheffer. All rights reserved. Stable Isotope Food Web Analysis of a Large Subtropical Lake: Alternative Explanations for 15N Enrichment of Pelagic vs. Littoral Fisheries Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2003/739301/abs/ The food webs of littoral, pelagic, and littoral-pelagic ecotone (interface) regions of a large subtropical lake were investigated using stable isotope ratio methods, expanding the focus of a previous fish-only study to include other food web components such as primary producers and invertebrates. In these food webs, δ13C increased ~4o/oo and δ15N increased ~10o/oo from primary producers to fish. The δ15N of fish was ~9o/oo in the littoral zone, ~10 o/oo in the ecotone, and ~12o/oo in the pelagic zone. The cross-habitat enrichment in fish 15N corresponded with both an increase in the size of fish and an increase in the δ15N of primary consumers (mollusks). Despite larger body size in the pelagic zone, fish in all three habitats appear to occur at the same average trophic level (TL = 4), assuming an enrichment factor of 3.4o/oo per trophic level, and normalizing to the δ15N of primary consumers. Karl E. Havens, Binhe Gu, Brian Fry, and Carol Kendall Copyright © 2003 Karl E. Havens et al. All rights reserved. Heavy Metal Accumulation in Soil Amended with Roadside Pond Sediment and Uptake by Winter Wheat (Triticum aestivum L. cv. PBW 343) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2010/750697/ The risks of heavy metal accumulation and the dynamics related to roadside pond sediment application in comparison to control of winter wheat (Triticum aestivum L.) were investigated in field experiments. Selective sequential extraction procedures revealed that application of pond sediment in soil increases the labile pools of the studied heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn). Risk assessment codes concluded that Cu and Pb were in the high-risk zone in both pond sediment and soil amended with pond sediment, whereas Zn and Cu were found in the medium-risk zone for control soil. Heavy metal accumulation by wheat straw and grain (39.38, 1.18, 23.73, 0.36, 0.18, and 16.8 mg kg-1 for Zn, Cd, Cu, Cr, Ni, and Pb, respectively, for wheat grain) was significantly increased through application of pond sediment. However, metal accumulation did not thwart the enhancement of wheat yield when pond sediment was applied. Health risk indexes of analyzed heavy metals were found to be within the Indian permissible limit for foodstuffs. Pond sediments help to fortify wheat grain by increasing the concentration of Zn and Cu as a source of micronutrients in the diet. However, a significant increase of Pb in wheat grain through pond sediment could be a health concern for its long-term application. Therefore, pond sediment would be a valuable resource for agriculture as an alternative organic supplement, but long-term use may require the cessation of the excavated sediment as agricultural landfill in order to restrict heavy metal contamination through it. Tanmoy Karak and Pradip Bhattacharyya Copyright © 2010 Tanmoy Karak and Pradip Bhattacharyya. All rights reserved. Applying Nitrogen Site-Specifically Using Soil Electrical Conductivity Maps and Precision Agriculture Technology Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/706285/abs/ Soil texture varies significantly within many agricultural fields. The physical properties of soil, such as soil texture, have a direct effect on water holding capacity, cation exchange capacity, crop yield, production capability, and nitrogen (N) loss variations within a field. In short, mobile nutrients are used, lost, and stored differently as soil textures vary. A uniform application of N to varying soils results in a wide range of N availability to the crop. N applied in excess of crop usage results in a waste of the grower’s input expense, a potential negative effect on the environment, and in some crops a reduction of crop quality, yield, and harvestability. Inadequate N levels represent a lost opportunity for crop yield and profit. The global positioning system (GPS)-referenced mapping of bulk soil electrical conductivity (EC) has been shown to serve as an effective proxy for soil texture and other soil properties. Soils with a high clay content conduct more electricity than coarser textured soils, which results in higher EC values. This paper will describe the EC mapping process and provide case studies of site-specific N applications based on EC maps. Results of these case studies suggest that N can be managed site-specifically using a variety of management practices, including soil sampling, variable yield goals, and cropping history. E.D. Lund, M.C. Wolcott, and G.P. Hanson Copyright © 2001 E.D. Lund et al. All rights reserved. The Marine Food Chain in Relation to Biodiversity Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/713693/abs/ Biodiversity provides “raw materials” for the food chain and seafood production, and also influences the capacity of ecosystems to perform these and other services. Harvested marine seafood species now exceed 100 million t y -1 and provide about 6% of all protein and 17% of animal protein consumed by humans. These resources include representatives from about nine biologically diverse groups of plants and animals. Fish account for most of the world’s marine catches, of which only 40 species are taken in abundance. Highest primary productivity and the richest fisheries are found within Exclusive Economic Zones (EEZ). This narrow strip (200 nautical mile/370 km wide) is not only the site of coastal “food factories” but also the area associated with heaviest perturbation to the marine environment. Structural redundancy is evident in marine ecosystems, in that many species are interchangeable in the way they characterise assemblage composition. While there is probably functional redundancy within groups, the effects of species loss on ecosystem performance cannot be easily predicted. In particular, the degree to which biodiversity per se is needed for ecosystem services, including seafood/fishery production, is poorly understood. Many human activities, including unsustainable fishing and mariculture, lead to erosion of marine biodiversity. This can undermine the biophysical cornerstones of fisheries and have other undesirable environmental side effects. Of direct concern are “species effects”, in particular the removal of target and non-target fishery species, as well as conservationally important fauna. Equally disrupting but less immediate are “ecosystem effects”, such as fishing down the food web, following a shift from harvested species of high to low trophic level. Physical and biological disturbances from trawl nets and dynamite fishing on coral reefs can also severely impact ecosystem structure and function. “Broadscale” biological and social effects brought about by fishing carry even more far-reaching consequences. For example, fishing itself can change the age at which sexual maturity is reached, thus affecting the reproductive status of the stock. Hence, fishing may be regarded as a mediator of evolution. Social impacts include conflicts over fish prices and policies arising from heavy fishing and inadequate institutional structures. Measures to increase the sustainability of catches and of biodiversity need to be much more tightly coupled. Promising approaches include use of bio-economic indicators and fully protected marine areas. High- and local-level governance options are also examined. Use of expert systems incorporating “fuzzy logic” are providing useful environmental insights in the ASEAN countries and other parts of the world, and have applications in fishery management and biodiversity conservation. Andrew R.G. Price Copyright © 2001 Andrew R.G. Price. All rights reserved. Assessment of Land-Use Impact on Macroinvertebrate Communities in the Zwalm River Basin (Flanders, Belgium) Using Multivariate Analysis and Geographic Information Systems Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/723508/abs/ Relationships between land-use and river water quality assessed by means of biological and physical-chemical variables and habitat characteristics were analysed for the Zwalm River basin in Flanders (Belgium). The research focussed on three zones within this river basin, each characterized by different land uses, and consequently, different types of pollution, mainly of diffuse origin. Environmental data have been integrated within a Geographic Information System. Possible relationships between aquatic ecosystem and land-use variables were searched for by means of multivariate analysis. Veronique Adriaenssens, Peter L. M. Goethals, and Niels De Pauw Copyright © 2002 Veronique Adriaenssens et al. All rights reserved. A Blueprint for the Problem Formulation Phase of EPA-Type Ecological Risk Assessments for 316(b) Determinations Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/645930/abs/ The difference between management objectives focused on sustainability of fish populations and the indigenous aquatic community, and a management objective focused on minimizing entrainment and impingement losses accounts for much of the ongoing controversy surrounding §316(b). We describe the EPA’s ecological risk assessment framework and recommend that this framework be used to more effectively address differences in management objectives and structure §316(b) determinations. We provide a blueprint for the problem formulation phase of EPA-type ecological risk assessments for cooling-water intake structures (CWIS) at existing power plant facilities. Our management objectives, assessment endpoints, conceptual model, and generic analysis plan apply to all existing facilities. However, adapting the problem formulation process for a specific facility requires consideration of the permitting agency’s guidelines and level of regulatory concern, as well as site-specific ecological and technical differences. The facility-specific problem formulation phase is designed around the hierarchy of biolo gical levels of organization in the generic conceptual model and the sequence of cause-effect events and risk hypotheses represented by this model. Problem formulation is designed to be flexible in that it can be tailored for facilities where §316(b) regulatory concern is low or high. For some facilities, we anticipate that the assessment can be completed based on consideration of susceptibility alone. At the other extreme, a high level of regulatory concern combined with the availability of extensive information and consideration of costly CWIS mitigation options may result in the ecological risk assessment relying on analyses at all levels. Decisions on whether to extend the ecological risk assessment to additional levels should be based on whether regulatory or generator concerns merit additional analyses and whether available information is adequate to support such analyses. In making these decisions, the functional dependence between levels of analysis must be considered in making the transition to the analysis phase and risk estimation component of the ecological risk assessment. Regardless of how the generic analysis plan is modified to develop a facility-specific analysis plan, the resulting plan should be viewed as a tool for comparing representative species and alternative CWIS options by focusing on relative changes (i.e., proportional or percent changes) in various measures. The analysis plan is specifically designed to encourage consideration of multiple lines of evidence and to characterize uncertainties in each line of evidence. Multiple lines of evidence from different levels of analysis, obtained using both prospective and retrospective techniques, provide a broader perspective on the magnitude of potential effects and associated uncertainties and risks. The implications of the EPA’s recent (April 2002) proposed regulations for existing facilities on the applicability of this blueprint are briefly considered. Webster Van Winkle, William P. Dey, Steve M. Jinks, Mark S. Bevlhimer, and Charles C. Coutant Copyright © 2002 Webster Van Winkle et al. All rights reserved. Retention and Internal Loading of Phosphorus in Shallow, Eutrophic Lakes Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/676350/abs/ This paper gives a general overview of the nature and important mechanisms behind internal loading of phosphorus (P), which is a phenomenon appearing frequently in shallow, eutrophic lakes upon a reduction of the external loading. Lake water quality is therefore not improved as expected. In particular summer concentrations rise and P retention may be negative during most of the summer. The P release originates from a pool accumulated in the sediment when the external loading was high. In most lake sediments, P bound to redox-sensitive iron compounds or P fixed in more or less labile organic forms constitute major fractions forms that are potentially mobile and eventually may be released to the lake water. The duration of the recovery period following P loading reduction depends on the loading history, but it may last for decades in lakes with a high sediment P accumulation. During the phase of recovery, both the duration and net P release rates from the sediment seem to decline progressively. Internal P loading is highly influenced by the biological structure as illustrated by lakes shifting from the turbid to the clearwater state as a result of, for example, biomanipulation. In these lakes P concentrations may be reduced to 50% of the pre-biomanipulation level and the period with negative retention during summer can thus be reduced considerably. The duration of internal loading can be reduced significantly by different restoration methods such as dredging to remove accumulated P or addition of iron or alum to elevate the sorption capacity of sediments. However, an important prerequisite for achieving long-term benefits to water quality is a sufficient reduction of the external P loading. Martin Sondergaard, Peder Jens Jensen, and Erik Jeppesen Copyright © 2001 Martin Sondergaard et al. All rights reserved. IUFRO Research Group 7.01 “Impacts of Air Pollution and Climate Change on Forest Ecosystems” Riverside, California, September 10-15, 2006 Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/676382/abs/ Copyright © 2007 TheScientificWorldJOURNAL. All rights reserved. Toward a Consistent Pattern of Ecosystem Theories Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/676819/abs/ Several ecosystem theories have been presented during the last 2–3 decades. Lately it has been possible to unite these theories into a consistent pattern. Intensive discussions at meetings have been the key to the formation of this pattern of ecosystem theories. Another driving factor has been the reformulation of E.P. Odum’s attributes1 into three growth forms: growth of the physical structure (the biomass), growth of the network (more cycling, more linkages), and growth of information. An analysis of the growth forms2 shows that through-flow (power), ascendancy, and exergy storage are all increasing as a consequence of all three types of growth. However, exergy dissipation, entropy production, specific exergy (exergy/biomass), retention time, and the ratio indirect/direct effect only increases or decreases with one or two of the growth forms. Sven Erik Jorgensen Copyright © 2001 Sven Erik Jorgensen. All rights reserved. Measurement Error Affects Risk Estimates for Recruitment to the Hudson River Stock of Striped Bass Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/678715/abs/ We examined the consequences of ignoring the distinction between measurement error and natural variability in an assessment of risk to the Hudson River stock of striped bass posed by entrainment at the Bowline Point, Indian Point, and Roseton power plants. Risk was defined as the probability that recruitment of age-1+ striped bass would decline by 80% or more, relative to the equilibrium value, at least once during the time periods examined (1, 5, 10, and 15 years). Measurement error, estimated using two abundance indices from independent beach seine surveys conducted on the Hudson River, accounted for 50% of the variability in one index and 56% of the variability in the other. If a measurement error of 50% was ignored and all of the variability in abundance was attributed to natural causes, the risk that recruitment of age-1+ striped bass would decline by 80% or more after 15 years was 0.308 at the current level of entrainment mortality (11%). However, the risk decreased almost tenfold (0.032) if a measurement error of 50% was considered. The change in risk attributable to decreasing the entrainment mortality rate from 11 to 0% was very small (0.009) and similar in magnitude to the change in risk associated with an action proposed in Amendment #5 to the Interstate Fishery Management Plan for Atlantic striped bass (0.006)— an increase in the instantaneous fishing mortality rate from 0.33 to 0.4. The proposed increase in fishing mortality was not considered an adverse environmental impact, which suggests that potentially costly efforts to reduce entrainment mortality on the Hudson River stock of striped bass are not warranted. Dennis J. Dunning, Quentin E. Ross, Stephan B. Munch, and Lev R. Ginzburg Copyright © 2002 Dennis J. Dunning et al. All rights reserved. Individual-Based Modelling Potentials and Limitations Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/684985/abs/ Individual-based modelling (IBM) is an important option in ecology for the study of specific properties of complex ecological interaction networks. The main application of this model type is the analysis of population characteristics at high resolution. IBM also contributes to the advancement of ecological theory. One of the remarkable potentials of the approach is the possibility of studying self-organization and emergent properties that arise from individual actions on higher integration levels, especially on the population level. Broder Breckling Copyright © 2002 Broder Breckling. All rights reserved. Factors Influencing Spatial Variability in Nitrogen Processing in Nitrogen-Saturated Soils Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/686417/abs/ Nitrogen (N) saturation is an environmental concern for forests in the eastern U.S. Although several watersheds of the Fernow Experimental Forest (FEF), West Virginia exhibit symptoms of N saturation, many watersheds display a high degree of spatial variability in soil N processing. This study examined the effects of temperature on net N mineralization and nitrification in N-saturated soils from FEF, and how these effects varied between high N-processing vs. low N-processing soils collected from two watersheds, WS3 (fertilized with [NH4]2SO4) and WS4 (untreated control). Samples of forest floor material (O1 horizon) and mineral soil (to a 5-cm depth) were taken from three subplots within each of four plots that represented the extremes of highest and lowest rates of net N mineralization and nitrification (hereafter, high N and low N, respectively) of untreated WS4 and N-treated WS3: control/low N, control/high N, N-treated/low N, N-treated/high N. Forest floor material was analyzed for carbon (C), lignin, and N. Subsamples of mineral soil were extracted immediately with 1 N KCl and analyzed for NH4+ and NO3- to determine preincubation levels. Extracts were also analyzed for Mg, Ca, Al, and pH. To test the hypothesis that the lack of net nitrification observed in field incubations on the untreated/low N plot was the result of absence of nitrifier populations, we characterized the bacterial community involved in N cycling by amplification of amoA genes. Remaining soil was incubated for 28 d at three temperatures (10, 20, and 30°C), followed by 1 NKCl extraction and analysis for NH4+ and NO3-. Net nitrification was essentially 100% of net N mineralization for all samples combined. Nitrification rates from lab incubations at all temperatures supported earlier observations based on field incubations. At 30°C, rates from N-treated/high N were three times those of N-treated/low N. Highest rates were found for untreated/high N (two times greater than those of N-treated/high N), whereas untreated/low N exhibited no net nitrification. However, soils exhibiting no net nitrification tested positive for presence of nitrifying bacteria, causing us to reject our initial hypothesis. We hypothesize that nitrifier populations in such soil are being inhibited by a combination of low Ca to Al ratios in mineral soil and allelopathic interactions with mycorrhizae of ericaceous species in the herbaceous layer. Frank S. Gilliam, Frank C.C. Somerville, Frank N.L. Lyttle, and Frank M.B. Adams Copyright © 2001 Frank S. Gilliam et al. All rights reserved. Effect of Interactions on the Nutrient Status of a Tropical Soil Treated with Green Manures and Inorganic Phosphate Fertilizers Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2004/695128/abs/ Integrated nutrient management systems using plant residues and inorganic P fertilizers have high potential for increasing crop production and ensuring sustainability in the tropics, but their adoption requires in-depth understanding of nutrient dynamics in such systems. This was examined in a highly weathered tropical soil treated with green manures (GMs) and P fertilizers in two experiments conducted in the laboratory and glasshouse. The treatments were factorial combinations of the GMs (Calopogonium caeruleum, Gliricidia sepium, and Imperata cylindrica) and P fertilizers (phosphate rocks [PRs] from North Carolina, China, and Algeria, and triple superphosphate) replicated thrice. Olsen P, mineral N, pH, and exchangeable K, Ca, and Mg were monitored in a laboratory incubation study for 16 months. The change in soil P fractions and available P was also determined at the end of the study. Phosphorus available from the amendments was quantified at monthly intervals for 5 months by 33P-32P double isotopic labeling in the glasshouse using Setaria sphacelata as test crop. The GMs were labeled with 33P to determine their contribution to P taken up by Setaria, while that from the P fertilizers was indirectly measured by labeling the soil with 32P. The P fertilizers hardly changed Olsen P and exchangeable cations during 16 months of incubation. The legume GMs and legume GM+P did not change Olsen P, lowered exchangeable Ca, and increased exchangeable K about threefold (4.5 cmol[+]kg−1 soil) in the first 4 months, even as large amounts of NH4-N accumulated (~1000 mg kg soil−1) and soil pH increased to more than 6.5. Afterwards, Olsen P and exchangeable Ca and Mg increased (threefold) as NH4+-N and soil pH declined. The legume GMs also augmented reversibly sorbed P in Al-P and Fe-P fractions resulting in high residual effect in the soil, while fertilizer-P was irreversibly retained. The GMs increased PR-P utilization by 40 to over 80%, mobilized soil P, and markedly enhanced uptake of N, K, Ca, and Mg. Thus GMs+PRs is an appropriate combination for correcting nutrient deficiencies in tropical soils. Abdul R. Bah, Zaharah A. Rahman, and Aminuddin Hussin Copyright © 2004 Abdul R. Bah et al. All rights reserved. Nitrogen Accumulation in Forests. Exposure Monitoring by Mosses Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/702363/abs/ At present, there is still little information on nitrogen (N) accumulation in forests contrasting with the crucial importance of N in forest ecosystems. This work analyzes the N bioaccumulation in mosses from forested areas from Lower Saxony and North Rhine-Westphalia (two of 16 federal states of Germany), the Weser Ems Region (part of Lower Saxony), and the Euro Region Nissa (covering the Czech Republic, Germany, Poland). The studies involved samples collected from 190 sites between 1998 and 2005. Different spatial scales and regional differences in land use were chosen to assess the factors affecting N bioaccumulation in forested areas. A continuous reduction of N bioaccumulation was found from Lower Saxony (a region where agriculture is most predominant) to North Rhine-Westphalia (mostly urban). The Weser Ems Region (an agricultural region) showed a higher N concentration in mosses than the Euroregion Nissa (a former industrial region). Statistical analyses performed at the different spatial scales revealed that the areas showing greater agricultural and livestock spatial densities favor N bioaccumulation in mosses. N concentration in mosses was moderately correlated with the N concentration in the leaves and needles of the surrounding trees. No significant relationships were found regarding the crown density of forest trees or N deposition estimations from a combination of atmospheric models and deposition measurements. Roland Pesch, Winfried Schröder, and Gunther Schmidt Copyright © 2007 Roland Pesch et al. All rights reserved. Temporally Dissociated, Trait-Specific Modifications Underlie Phenotypic Polyphenism in Spea multiplicata Tadpoles, Which Suggests Modularity Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/792039/abs/ Many organisms that develop in a variable environment show correlated patterns of phenotypic plasticity in several traits. Any individual trait modification can be beneficial, neutral, or deleterious in any particular environment; the organism's total fitness, which determines if the plasticity is adaptive, is the sum of these changes. Although much is known about how plastic traits contribute to fitness, less is known about the extent to which the various trait changes involved in the plastic responses share their developmental control. Shared control suggests that the various responses evolved in unison, but independent control suggests independent evolution of many components. Spadefoot toads have evolved adaptive polyphenism to cope with developing in rapidly drying ephemeral ponds. Larvae hatch as omnivores, but on exposure to an environmental cue, may develop into carnivores. We compared trait development in the two morphs and found that differences in jaw musculature, head dimensions, and intestines emerged early in development, whereas differences in shape of the tail emerged later. In omnivores, all traits except intestine length and hind-limb length were negatively allometric with body length; in carnivores, two of three jaw muscles displayed positive allometry and, among those that were negatively allometric, all except head width showed larger allometric coefficients in carnivores. Hind-limb length was positively allometric in both forms, but the allometric coefficients did not differ significantly. Intestine length was positively allometric to body length in both forms, but in this case, omnivores exhibited the higher coefficient. These results suggest that spadefoot plasticity is trait specific and the responses are suggestive of the existence of at least two modules: a suite of trophic traits that responds early in development and a suite of tail traits that responds later. The developmental control of these suites is the subject of further investigation. Brian L. Storz and Joseph Travis Copyright © 2007 Brian L. Storz and Joseph Travis. All rights reserved. Historical Transition of Eco-Structure in a Tidal Flat Caused by Expansion of Sewerage Treatment Area Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2004/792401/abs/ An artificial tidal flat was prepared for the mitigation tool on coastal environment. However, it is considered that most of the flat was not restored to the sufficient amenities for aquatic living things, migratory birds, etc. because none of the ecological mechanisms were understood or planned for. It is therefore investigated in this paper that historical transition factors in ecosystem structure are selected and traced with the diffusion of a public sewerage system, and with environmental factors such as water quality, sediment condition, and aquatic producers in the Yatsu Tidal Flat. As a result, it can be defined that the tidal flat, just like a lagoon, was formed artificially with reclamation and development of its circumference at the first step of transition; the water quality and sediment condition gradually became brackish water and muddy sediment conditions, interactively. The ecosystem pyramid forming orderly layers according to trophic level appeared as a high-bio-production potential in its tidal flat. In the second step, i.e., in recent years, the characteristics of water quality and sediment conditions evolved into a foreshore tidal flat, namely, conditions in the flat observed were that the progression of water included a high concentration of chloride ion as seawater and sediment conditions became sandy. Because of that, the inflowing fresh water and organic mater from the land area decreased with the improvement of the public sewerage system. The ecosystem pyramid was distorted into a chaos pyramid, with inversion of Ulva spp. Hideki Tatsumoto, Yuichi Ishii, Motoi Machida, and Kazuo Taki Copyright © 2004 Hideki Tatsumoto et al. All rights reserved. Community Structure of Terrestrial Invertebrates Inhabiting a Tidal Marsh Islet in the Mediterranean Sea (Gulf of Gabes, Tunisia) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/794847/abs/ The composition of the terrestrial arthropod community of a tidal marsh islet in the Gulf of Gabes (Tunisia) was studied during two seasons (spring, autumn). The study was conducted on a small islet located in an area where the highest tidal excursions of the Mediterranean occur. Standard trapping methods (pitfall traps, mobile cages) were used to evaluate specie richness and abundance in different areas of the islet. Diversity indices were calculated for coleopterans and isopods alone. The structure of the arthropod community varied a great deal from one season to the other and differences were found when seaward areas were compared with landward ones. El Bessila presented a particularly rich beetle community whereas only few isopod species occurred. The moderately high diversity levels found for the beetle indicate the influence of the high tidal excursions in modelling the structure of the community. I. Colombini, L. Chelazzi, and M. Fallaci Copyright © 2002 I. Colombini et al. All rights reserved. Forest Health Status in North America Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/753401/abs/ The forests of North America provide a variety of benefits including water, recreation, wildlife habitat, timber, and other forest products. However, they continue to face many biotic and abiotic stressors including fires, native and invasive pests, fragmentation, and air pollution. Forest health specialists have been monitoring the health of forests for many years. This paper highlights some of the most damaging forest stressors affecting North American forests in recent years and provides some projections of future risks. Borys Tkacz, Ben Moody, and Jaime Villa Castillo Copyright © 2007 Borys Tkacz et al. All rights reserved. Ecosystem Management and Ecological Modeling Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/758256/abs/ It is the intention of this paper to demonstrate that environmental technology must be supplemented by other tools to be able to solve environmental problems properly. Five cases are used to illustrate the possibilities of ecological engineering, a new engineering field based on ecology, as chemical engineering is based on chemistry. It encompasses restoration of ecosystems, utilization of ecosystems to the benefit of both mankind and nature, construction of ecosystems, and ecologically sound planning of ecosystems from a holistic point of view. Ecological engineering requires a good knowledge of the system properties of ecosystems to be able to fully utilize the possibilities that ecosystem management offers. Models reflecting the ecosystem properties are furthermore needed to be able to quantify the effects of the ecological engineering solutions to the environmental problems. This is clearly demonstrated in two of the five case studies presented in the paper. S.E. JØrgensen Copyright © 2002 S.E. Jorgensen. All rights reserved. Impacts of Air Pollution and Climate Change on Forest Ecosystems — Emerging Research Needs Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/783864/abs/ Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems “Forests under Anthropogenic Pressure Effects of Air Pollution, Climate Change and Urban Development”, September 1016, 2006, Riverside, CA, are summarized. Tropospheric or ground-level ozone (O3) is still the phytotoxic air pollutant of major interest. Challenging issues are how to make O3 standards or critical levels more biologically based and at the same time practical for wide use; quantification of plant detoxification processes in flux modeling; inclusion of multiple environmental stresses in critical load determinations; new concept development for nitrogen saturation; interactions between air pollution, climate, and forest pests; effects of forest fire on air quality; the capacity of forests to sequester carbon under changing climatic conditions and coexposure to elevated levels of air pollutants; enhanced linkage between molecular biology, biochemistry, physiology, and morphological traits. Elena Paoletti, Andrzej Bytnerowicz, Chris Andersen, Algirdas Augustaitis, Marco Ferretti, Nancy Grulke, Madeleine S. Günthardt-Goerg, John Innes, Dale Johnson, Dave Karnosky, Jesada Luangjame, Rainer Matyssek, Steven McNulty, Gerhard Müller-Starck, Robert Musselman, and Kevin Percy Copyright © 2007 Elena Paoletti et al. All rights reserved. Smog Nitrogen and the Rapid Acidification of Forest Soil, San Bernardino Mountains, Southern California Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/784903/abs/ We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the soil surface (72 kg ha–1 year–1) from wet, dry, and fog deposition under a Mediterranean climate. Our research suggests that a soil textural discontinuity, related to a buried ancient landsurface, contributes to this rapid acidification by controlling the spatial and temporal movement of precipitation into the landsurface. As a result, the depth to which dissolved anthropogenic N as nitrate (NO3) is leached early in the winter wet season is limited to within the top ~130 cm of soil where it accumulates and increases soil acidity. Yvonne A. Wood, Mark Fenn, Thomas Meixner, Peter J. Shouse, Joan Breiner, Edith Allen, and Laosheng Wu Copyright © 2007 Yvonne A. Wood et al. All rights reserved. Modeling of Nitrogen Dynamics in an Austrian Alpine Forest Ecosystem on Calcareous Soils: A Scenario-Based Risk Assessment under Changing Environmental Conditions Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/786238/abs/ We modeled the behavior of an Austrian alpine forest ecosystem on calcareous soils under changing climate and atmospheric nitrogen deposition scenarios. The change of nitrate leaching, emission rates of nitrogen compounds, and forest productivity were calculated using four process-oriented models for the periods 1998–2002 and 2048–2052. Each model reflects with high detail a segment of the ecosystem: PnET-N-DNDC (photosynthesis-evapotranspiration-nitrification-denitrification-decomposition; shortterm nitrogen cycling), BROOK90 (water balance for small and homogenous forest watersheds), HYDRUS (water flux in complex and heterogenous soils), and PICUS v1.3 (forest productivity). The nitrogen balance model (NBM) combines the individual results into a comprehensive picture and extends the specific values beyond the limits of the individual models. The evaluation of the findings was outlined with TRACE, a model enabling a long-term prognosis of nitrogen cycling in annual time steps. Friedl Herman, Stefan Smidt, Klaus Butterbach-Bahl, Michael Englisch, Ernst Gebetsroither, Robert Jandl, Klaus Katzensteiner, Manfred Lexer, Friederike Strebl, and Sophie Zechmeister-Boltenstern Copyright © 2007 Friedl Herman et al. All rights reserved. Defining “Adverse Environmental Impact” and Making § 316(b) Decisions: A Fisheries Management Approach Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/814394/abs/ The electric utility industry has developed an approach for decisionmaking that includes a definition of Adverse Environmental Impact (AEI) and an implementation process. The definition of AEI is based on lessons from fishery management science and analysis of the statutory term “adverse environmental impact” and is consistent with current natural resource management policy. The industry has proposed a definition focusing on “unacceptable risk to the population’s ability to sustain itself, to support reasonably anticipated commercial or recreational harvests, or to perform its normal ecological function.” This definition focuses not on counting individual fish or eggs cropped by the various uses of a water body, but on preserving populations of aquatic organisms and their functions in the aquatic community. The definition recognizes that assessment of AEI should be site-specific and requires both a biological decision and a balancing of diverse societal values. The industry believes that the definition of AEI should be implemented in a process that will maximize the overall societal benefit of the § 316(b) decision by considering the facility’s physical location, design, and operation, as well as the local biology. The approach considers effects on affected fish and shellfish populations and the benefits of any necessary best technology available (BTA) alternatives. This is accomplished through consideration of population impacts, which conversely allows consideration of the benefits of any necessary BTA modifications. This in turn allows selection of BTAs that will protect potentially affected populations in a cost-effective manner. The process also employs risk assessment with stakeholder participation, in accordance with EPA’s Guidelines for Ecological Risk Assessment. The information and tools are now available to make informed decisions about site-specific impacts that will ensure protection of aquatic ecosystems and best serve the public interest. David E. Bailey and Kristy A.N. Bulleit Copyright © 2002 David E. Bailey and Kristy A.N. Bulleit. All rights reserved. A Throughfall Collection Method Using Mixed Bed Ion Exchange Resin Columns Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/832087/abs/ Measurement of ionic deposition in throughfall is a widely used method for measuring deposition inputs to the forest floor. Many studies have been published, providing a large database of throughfall deposition inputs to forests. However, throughfall collection and analysis is labor intensive and expensive because of the large number of replicate collectors needed and because sample collection and chemical analyses are required on a stochastic precipitation event-based schedule. Therefore we developed and tested a throughfall collector system using a mixed bed ion exchange resin column. We anticipate that this method will typically require only one to three samplings per year. With this method, bulk deposition and bulk throughfall are collected by a funnel or snow tube and ions are retained as the solution percolates through the resin column. Ions retained by the resin are then extracted in the same column with 2N KCl and analyzed for nitrate and ammonium. Deposition values in throughfall from conventional throughfall solution collectors and colocated ion exchange samplers were not significantly different during consecutive 3- and 4-month exposure periods at a high (Camp Paivika; >35 kg N ha-1 year-1) and a low deposition (Barton Flats; 5–9 kg N ha-1 year-1) site in the San Bernardino Mountains in southern California. N deposition in throughfall under mature pine trees at Camp Paivika after 7 months of exposure was extremely high (87 and 92 kg ha-1 based on the two collector types) compared to Barton Flats (11 and 13 kg ha-1). A large proportion of the N deposited in throughfall at Camp Paivika occurred as fog drip, demonstrating the importance of fog deposition as an input source of N at this site. By comparison, bulk deposition rates in open areas were 5.1 and 5.4 kg ha-1 at Camp Paivika based on the two collector types, and 1.9 and 3.0 kg ha-1 at Barton Flats. Mark E. Fenn, Mark A. Poth, and Michael J. Arbaugh Copyright © 2002 Mark E. Fenn et al. All rights reserved. Effects of Temperature, Salinity, pH, and Light on Filtering and Grazing Rates of a Calanoid Copepod (Schmackeria dubia) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/838071/ Calanoid copepods are key components of the marine food web and the food sources of many larval fishes and planktivores, and grazers of phytoplankton. Understanding the ranges of major environmental variables suitable for their growth is essential to maintain the balance between trophic links and resources protection. In this study, the effects of temperature, salinity, pH, and light intensity on the filtering and grazing rates of a herbivorous copepod (Schmackeria dubia) were conducted in several control experiments. Our results indicated that experimental animals grazed normally at water temperatures between 15 and 35°C. The filtering and grazing rates increased by onefold at water temperatures from 15 to 25°C, with a peak at around 30°C. S. dubia fed normally at salinity ranging from 20 to 30 ppt, with significantly low filtering and grazing rates at salinity below 15 ppt and above 35 ppt. The filtering and grazing rates increased as pH increased, peaked at approximately 8.5, and then decreased substantially. Light intensity also displayed an important impact on the filtering and grazing rates. Filtering and grazing rates were high when light intensity was greater than 20 and less than 200 µmol m-2 s-1. S. dubia nearly stopped feeding at low light intensity (less than 20 µmol m-2 s-1). Changling Li, Xiaoxia Luo, Xianghu Huang, and Binhe Gu Copyright © 2008 Changling Li et al. All rights reserved. Large-Scale Mapping and Predictive Modeling of Submerged Aquatic Vegetation in a Shallow Eutrophic Lake Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/596106/abs/ A spatially intensive sampling program was developed for mapping the submerged aquatic vegetation (SAV) over an area of approximately 20,000 ha in a large, shallow lake in Florida, U.S. The sampling program integrates Geographic Information System (GIS) technology with traditional field sampling of SAV and has the capability of producing robust vegetation maps under a wide range of conditions, including high turbidity, variable depth (0 to 2 m), and variable sediment types. Based on sampling carried out in AugustœSeptember 2000, we measured 1,050 to 4,300 ha of vascular SAV species and approximately 14,000 ha of the macroalga Chara spp. The results were similar to those reported in the early 1990s, when the last large-scale SAV sampling occurred. Occurrence of Chara was strongly associated with peat sediments, and maximal depths of occurrence varied between sediment types (mud, sand, rock, and peat). A simple model of Chara occurrence, based only on water depth, had an accuracy of 55%. It predicted occurrence of Chara over large areas where the plant actually was not found. A model based on sediment type and depth had an accuracy of 75% and produced a spatial map very similar to that based on observations. While this approach needs to be validated with independent data in order to test its general utility, we believe it may have application elsewhere. The simple modeling approach could serve as a coarse-scale tool for evaluating effects of water level management on Chara populations. Karl E. Havens, Matthew C. Harwell, Mark A. Brady, Bruce Sharfstein, Therese L. East, Andrew J. Rodusky, Daniel Anson, and Ryan P. Maki Copyright © 2002 Karl E. Havens et al. All rights reserved. Air Pollution Distribution Patterns in the San Bernardino Mountains of Southern California: a 40-Year Perspective Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/597837/abs/ Since the mid-1950s, native pines in the San Bernardino Mountains (SBM) in southern California have shown symptoms of decline. Initial studies in 1963 showed that ozone (O3) generated in the upwind Los Angeles Basin was responsible for the injury and decline of sensitive trees. Ambient O3 decreased significantly by the mid-1990s, resulting in decreased O3 injury and improved tree growth. Increased growth of trees may also be attributed to elevated atmospheric nitrogen (N) deposition. Since most of the N deposition to mixed conifer forest stands in the SBM results from dry deposition of nitric acid vapor (HNO3) and ammonia (NH3), characterization of spatial and temporal distribution of these two pollutants has become essential. Although maximum daytime O3 concentrations over last 40 years have significantly decreased (~3-fold), seasonal means have been reduced much less (~1.5-fold), with 2-week long means occasionally exceeding 100 ppb in the western part of the range. In the same area, significantly elevated concentrations of HNO3 and NH3, up to 17.5 and 18.5 μg/m3 as 2-week averages, respectively, have been determined. Elevated levels of O3 and increased N deposition together with long-term drought predispose the SBM forests to massive bark beetle attacks making them susceptible to catastrophic fires. Andrzej Bytnerowicz, Michael Arbaugh, Susan Schilling, Witold Fraczek, Diane Alexander, and Philip Dawson Copyright © 2007 Andrzej Bytnerowicz et al. All rights reserved. Ethylenediurea (EDU) Affects the Growth of Ozone-Sensitive and Tolerant Ash (Fraxinus excelsior) Trees under Ambient O3 Conditions Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/602361/abs/ Adult ash trees (Fraxinus excelsior L.), known to be sensitive or tolerant to ozone, determined by presence or absence of foliar symptoms in previous years, were treated with ethylenediurea (EDU) at 450 ppm by gravitational trunk infusion over the 2005 growing season (32.5 ppm h AOT40). Tree and shoot growth were recorded in May and September. Leaf area, ectomycorrhizal infection, and leaf and fine root biomass were determined in September. EDU enhanced shoot length and diameter, and the number and area of leaves, in both O3-sensitive and tolerant trees. However, no EDU effects were recorded at the fine root and tree level. Therefore, a potential for EDU protection against O3-caused growth losses of forest trees should be evaluated during longer-term experiments. Elena Paoletti, Nicla Contran, William J. Manning, and Francesco Tagliaferro Copyright © 2007 Elena Paoletti et al. All rights reserved. Toward Molecular Level of the “Salmonella-Victim” Ecology, Genetics, and Evolution Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2004/578375/abs/ Bacteria of the Salmonella genus are polypathogenic agents that can affect both men and animals, causing devastating and fatal illness. Despite considerable immunological, epidemiological, and genetic efforts, and increased understanding of how the Salmonella infection develops, many key questions concerning Salmonella infection remain unanswered. Salmonella can be carried as harmless commensals in some sectors of the population. In some individuals, however, the same microbes cause illness while others display immunity to primary Salmonella infection. Nothing is known about the molecular base of the Salmonella pathogenicity. Even the ability of Salmonella to destroy the victim’s cells has been the subject of century-long discussions. In this article, some key findings concerning ecology, molecular ecology, and cell level of the Salmonella infection genetics are summarized and interpreted from the viewpoint of evolutionary theory with certitude that this approach can help to decipher the undiscovered secrets of Salmonella infection’s epidemiology and pathogenesis, as well as the clinical course and severity, and to select ways for fighting against Salmonella. S.N. Rumyantsev Copyright © 2004 S.N. Rumyantsev. All rights reserved. Indicators of AEI Applied to the Delaware Estuary Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/589782/abs/ We evaluated the impacts of entrainment and impingement at the Salem Generating Station on fish populations and communities in the Delaware Estuary. In the absence of an agreed-upon regulatory definition of “adverse environmental impact” (AEI), we developed three independent benchmarks of AEI based on observed or predicted changes that could threaten the sustainability of a population or the integrity of a community. Lawrence W. Barnthouse, Douglas G. Heimbuch, Vaughn C. Anthony, Ray W. Hilborn, and Ransom A. Myers Copyright © 2002 Lawrence W. Barnthouse et al. All rights reserved. Probabilistic Ecological Risk Assessment of OCPs, PCBs, and DLCs in the Haihe River, China Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2010/542970/ The Haihe River is the most seriously polluted river among the seven largest rivers in China. Dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and PCBs (noncoplanar polychlorinated biphenyls) in the Haihe River, Tianjin were determined using a gas chromatograph – electron capture detector (GC-ECD). Dioxin-like compounds (DLCs) were determined using Chemically Activated LUciferase gene eXpression (CALUX) bioassay. HCH and DDT levels were, respectively, 0.06–6.07 μg/L and ND (not detected) to 1.21 μg/L; PCB levels ranged from 0.12 to 5.29 μg/L; and the total DLCs in sediment were 4.78–343 pg TEQ (toxic equivalency)/g. Aquatic ecological risk assessment was performed using the joint probability curve method and the Monte Carlo-based HQ (hazard quotient) distribution method. The combined risks of similar chemicals and the total risk of dissimilar categories of chemicals were assessed based on the principles of joint toxicity. Due to the adjacent industrial activities, the risk levels of PCBs, DDTs, and HCHs were relatively high. The risk order was as follows: PCBs > DDTs ≈ HCHs > DLCs. The risk of HCHs approximated that of DDTs, which is different from the fact that risk of HCHs is usually much lower in the other Chinese rivers. The total risk caused by these pollutants was very high. Due to their high persistence and potential source from land, the high risks of such pollutants are likely to last for a long period of time. Bin Wang, Gang Yu, Jun Huang, Tai Wang, and Hongying Hu Copyright © 2010 Bin Wang et al. All rights reserved. Hurricane Effects on a Shallow Lake Ecosystem and Its Response to a Controlled Manipulation of Water Level Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/616414/abs/ In order to reverse the damage to aquatic plant communities caused by multiple years of high water levels in Lake Okeechobee, Florida (U.S.), the Governing Board of the South Florida Water Management District (SFWMD) authorized a "managed recession" to substantially lower the surface elevation of the lake in spring 2000. The operation was intended to achieve lower water levels for at least 8 weeks during the summer growing season, and was predicted to result in a large-scale recovery of submerged vascular plants. We treated this operation as a whole ecosystem experiment, and assessed ecological responses using data from an existing network of water quality and submerged plant monitoring sites. As a result of large-scale discharges of water from the lake, coupled with losses to evaporation and to water supply deliveries to agriculture and other regional users, the lake surface elevation receded by approximately 1 m between April and June. Water depths in shoreline areas that historically supported submerged plant communities declined from near 1.5 m to below 0.5 m. Low water levels persisted for the entire summer. Despite shallow depths, the initial response (in June 2000) of submerged plants was very limited and water remained highly turbid (due at first to abiotic seston and later to phytoplankton blooms). Turbidity decreased in July and the biomass of plants increased. However, submerged plant biomass did not exceed levels observed during summer 1999 (when water depths were greater) until August. Furthermore, a vascular plant-dominated assemblage (Vallisnera, Potamogeton, and Hydrilla) that occurred in 1999 was replaced with a community of nearly 98% Chara spp. (a macro-alga) in 2000. Hence, the lake’s submerged plant community appeared to revert to an earlier successional stage despite what appeared to be better conditions for growth. To explain this unexpected response, we evaluated the impacts that Hurricane Irene may have had on the lake in the previous autumn. In mid-October 1999, this category 1 hurricane passed just to the south of the lake, with wind velocities over the lake surface reaching 90 km h-1 at their peak. Output from a three-dimensional hydrodynamic / sediment transport model indicates that during the storm, current velocities in surface waters of the lake increased from near 5 cm s-1 to as high as 100 cm s-1. These strong velocities were associated with large-scale uplifting and horizontal transport of fine-grained sediments from the lake bottom. Water quality data collected after the storm confirmed that the hurricane resulted in lake-wide nutrient and suspended solids concentrations far in excess of those previously documented for a 10-year data set. These conditions persisted through the winter months and may have negatively impacted plants that remained in the lake at the end of the 1999 growing season. The results demonstrate that in shallow lakes, unpredictable external forces, such as hurricanes, can play a major role in ecosystem dynamics. In regions where these events are common (e.g., the tropics and subtropics), consideration should be given to how they might affect long-term lake management programs. Karl E. Havens, Kang-Ren Jin, Andrew J. Rodusky, Bruce Sharfstein, Mark A. Brady, Therese L. East, Nenad Iricanin, R. Thomas James, Matthew C. Harwell, and Alan D. Steinman Copyright © 2001 Karl E. Havens et al. All rights reserved. Analysis of Climate Change Affecting German Forests by Combination of Meteorological and Phenological Data within a GIS Environment Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/604592/abs/ The regional assessment of global change effects on plant phenology usually relies on local observations that need to be up-scaled. Therefore, methodological difficulties mostly related to data spatial resolution and congruency arise while performing broader-scale evaluations. Geostatiscs could be a useful tool to solve this type of problem, provided that a database with adequate spatial and temporal resolution is available. An assessment of variations in air temperature and plant phenology was carried out at the country level by using two German datasets regarding spring phenological phases of 15 plant species and air temperature. The data were collected from 1961–2002 at 1,279 and 675 sites, respectively. The annual mean air temperature in Germany was found to rise from 8.3°C in the 1961–1990 period to 9.1°C in the 1991–2002 term. The overall 15-species mean for the start of spring was found to be 6 days earlier in the latter period. The geostatistical analysis of the data revealed the suitability of Syringa vulgaris to be used as an indicator species to detect phenological changes in German forests. Moreover, their spatial patterns were found to be related to altitude and latitude. Therefore, geostatistics proved to be a useful tool to overcome some of the methodological problems related to the regional assessments of global change impacts on terrestrial ecosystems. Winfried Schröder, Roland Pesch, Gunther Schmidt, and Cordula Englert Copyright © 2007 Winfried Schröder et al. All rights reserved. Surface Level Ozone and its Adverse Effects on Crops and Forests: A Need for an Interdisciplinary Understanding Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/607680/abs/ Surface level ozone (O3) is clearly a global scale problem with regard to its adverse effects on crops, forests and native, terrestrial plant ecosystems. Photochemists and meteorologists are continuing to define the chemistry and physics of the prevalence of O3 at the ground level. Similarly, plant scientists in the U.S. and Europe have examined the effects of O3 on crops and tree seedlings or saplings through large-scale studies. Examples include the U.S. National Crop Loss Assessment Network (NCLAN), the U.S. EPA’s (Environmental Protection Agency’s) San Bernardino National Forest Photochemical Oxidant Study, European Open-top Chambers Programme (EOTCP), and several ongoing EU (European Union) projects. In addition, there have been studies on mature tree responses through field measurements and by simulation modeling. Sagar V. Krupa Copyright © 2001 Sagar V. Krupa. All rights reserved. Did the Ambient Ozone Affect Stem Increment of Scots Pines (Pinus sylvestris L.) on Territories under Regional Pollution Load? Step III of Lithuanian Studies Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/630957/abs/ This study aimed to explore if changes in stem increment of Scots pines (Pinus sylvestris L.) could be related to changes in ambient ozone concentration when the impact of tree dendrometric parameters (age, diameter) and crown defoliation are accounted for. More than 200 dominant and codominant trees from 12 pine stands, for which crown defoliation had been assessed since 1994, were chosen for increment boring and basal area increment computing. Stands are located in Lithuanian national parks, where since 1994–95 Integrated Monitoring Stations have been operating. Findings of the study provide statistical evidence that peak concentrations of ambient ozone (O3) can have a negative impact on pine tree stem growth under field conditions where O3 exposure is below phytotoxic levels. Algirdas Augustaitis, Ingrida Augustaitiene, Gintautas Cinga, Juozapas Mazeika, Romualdas Deltuvas, Romualdas Juknys, and Adomas Vitas Copyright © 2007 Algirdas Augustaitis et al. All rights reserved. Prediction on the Seasonal Behavior of Hydrogen Sulfide Using a Neural Network Model Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2011/545067/ Models to predict seasonal hydrogen sulfide (H2S) concentrations were constructed using neural networks. To this end, two types of generalized regression neural networks and radial basis function networks are considered and optimized. The input data for H2S were collected from August 2005 to Fall 2006 from a huge industrial complex located in Ansan City, Korea. Three types of seasonal groupings were prepared and one optimized model is built for each dataset. These optimized models were then used for the analysis of the sensitivity and main effect of the parameters. H2S was noted to be very sensitive to rainfall during the spring and summer. In the autumn, its sensitivity showed a strong dependency on wind speed and pressure. Pressure was identified as the most influential parameter during the spring and summer. In the autumn, relative humidity overwhelmingly affected H2S. It was noted that H2S maintained an inverse relationship with a number of parameters (e.g., radiation, wind speed, or dew-point temperature). In contrast, it exhibited a declining trend with a decrease in pressure. An increase in radiation was likely to decrease during spring and summer, but the opposite trend was predicted for the autumn. The overall results of this study thus suggest that the behavior of H2S can be accounted for by a diverse combination of meteorological parameters across seasons. Byungwhan Kim, Joogong Lee, Jungyoung Jang, Dongil Han, and Ki-Hyun Kim Copyright © 2011 Byungwhan Kim et al. All rights reserved. Heavy Metal Concentrations in the Spiders Pirata piraticus (Clerck, 1757) and Clubiona phragmitis (C.L. Koch, 1843) along the Scheldt Estuary (Belgium) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/561305/abs/ Wetland ecosystems may be affected by deposition and accumulation of heavy metals. Metal concentrations in the spiders Pirata piraticus and Clubiona phragmitis living in marshes along the river Scheldt (Flanders, Belgium) were analyzed. The organisms were sampled on seven sites along a gradient from freshwater to brackish marshes. Except for lead, P. piraticus contained higher metal concentrations than C. phragmitis. This is related to physiological and ecological differences between species. No correlation was found between metal concentration in the organisms and soil total concentration. Catarina Tojal, Frederik Hendrickx, Filip M.G. Tack, Jean-Pierre Maelfait, Nicolas Bogaert, Katrien Willems, Pieter Vernaillen, Johan Mertens, and Marc G. Verloo Copyright © 2002 Catarina Tojal et al. All rights reserved. Phenotypic Plasticity in Gut Length in the Planktivorous Filter-Feeding Silver Carp (Hypophthalmichthys molitrix) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/563687/ Phenotypic plasticity widely exists in the external morphology of animals as well as the internal traits of organs. In the present study, we studied the gut length plasticity of planktivorous filter-feeding silver carp under different food resources in large-net cage experiments in Meiliang Bay of Lake Taihu in 2004 and 2005. There was a significant difference in stocking density between these 2 years. Under a low stocking density and abundant food resources, silver carp increased their energy intake by feeding on more zooplankton. Meanwhile, silver carp adjusted their gut length to match the digestive requirements of food when exposed to different food resources. In the main growth seasons (from April to October), silver carp significantly increased their relative gut length when feeding on more phytoplankton in 2005 (p < 0.01, 9.23 ± 1.80 in 2004 and 10.77 ± 2.05 in 2005, respectively). There was a nearly significant negative correlation between zooplankton proportion in the diet and the relative gut length when silver carp were stocked in a high density (p = 0.112). It appears that silver carp might have evolved plasticity to change their gut length rapidly to facilitate efficient utilization of food resources. Such resource polymorphisms in the gut may be a good indication of temporal adaptation to resource conditions. Our work provided field evidence for understanding the functional basis of resource polymorphisms and the evolution of phenotypic plasticity in planktivorous filter-feeding fish. Zhixin Ke, Xie Ping, and Longgen Guo Copyright © 2008 Zhixin Ke et al. All rights reserved. Modeling Water Resources: Have We Got it Right? Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2000/572878/abs/ Aquatic scientists generally recognize that controlled experiments are required to establish cause-effect relationships (e.g., Havens and Aumen, 2000), and understanding ecological processes is key to accurately predicting complex ecosystem responses. However, resource managers may have at their disposal only a limited amount of observational data when faced with management decisions. Hence, there may be a tendency to use simple empirical models for decision making. An example of eutrophication management in lakes illustrates a pitfall of this approach when used independently of other scientific information. Karl E. Havens Copyright © 2000 Karl E. Havens. All rights reserved. Zooplankton Structure and Potential Food Web Interactions in the Plankton of a Subtropical Chain-of-Lakes Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/531050/abs/ This study evaluates the taxonomic and size structure of macro-zooplankton and its potential role in controlling phytoplankton in the Kissimmee Chain-of-Lakes, six shallow interconnected lakes in Florida, U.S. Macro-zooplankton species biomass and standard limnological attributes (temperature, pH, total phosphorus [TP], chlorophyll a [Chl a], and Secchi transparency) were quantified on a bimonthly basis from April 1997 to February 1999. Concentrations of TP ranged from below 50 to over 150 μg l-1. Peak concentrations of particulate P coincided with maximal Chl a, and in one instance a high concentration of soluble reactive P followed. The cladoceran zooplankton was dominated by small species, including Eubosmina tubicen, Ceriodaphnia rigaudi, and Daphnia ambigua. The exotic daphnid, D. lumholtzii, periodically was abundant. The copepods were strongly dominated by Diaptomus dorsalis, a species previously shown to be highly resistant to fish predation. These results, and findings of controlled experiments on a nearby lake with a nearly identical zooplankton species complement, suggest that fish predation may be a major factor structuring the macro-zooplankton assemblage. Zooplankton biomass, on the other hand, may be affected by resource availability. There was a significant positive relationship between average biomass of macro-zooplankton and the average concentration of TP among the six lakes. No such relationship existed between zooplankton biomass and Chl a, suggesting that the predominant food web in these systems may be based on bacteria-plankton, as has been documented in nearby Lake Okeechobee. All of the zooplankton taxa encountered in the Kissimmee Chain-of-Lakes (except Mesocyclops edax) are known bacteria grazers in Florida lakes. Phytoplankton biomass, measured as Chl a, was strongly associated with TP, both within and across lakes. Phytoplankton biomass was not associated with the biomass of zooplankton. These results, when considered in the context of nutrient-addition, zooplankton-exclosure studies on Lake Okeechobee, support the hypothesis that phytoplankton biomass in subtropical lakes is regulated by —bottom-up,“ rather than —top-down“ forces. Karl E. Havens Copyright © 2002 Karl E. Havens. All rights reserved. Use of Thermodynamic Orientors to Assess the Efficiency of Ecosystems: A Case Study in the Lagoon of Venice Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/534860/abs/ So-called orientors have been introduced at the interface between ecology and thermodynamics. Two have been chosen here to compare the characteristics of five ecological systems: exergy, which is related to the degree of organization of a system and represents the biogeochemical energy of a system, and emergy, which is defined as the total amount of solar energy directly or indirectly required to generate a product or a service. They represent two complementary aspects of a system: the actual state and the past work needed to reach that state. The ratio of exergy to the emergy flow indicates the efficiency of an ecosystem in producing or maintaining its organization. Simone Bastianoni Copyright © 2002 Simone�Bastianoni. All rights reserved. Collagen Fibrils in Cultured and Wild Sea Bream (Sparus aurata) Liver. An Electron Microscopy and Image Analysis Study Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2011/538413/ This study aims to measure liver collagen fibril diameter in cultured and wild sea breams (Sparus aurata). Cultured sea breams were fed three isonitrogenous diets. The organically produced feed contained sustainable certified fish meal (45%), fish oil (14%), and organic certified wheat; the laboratory feed contained fish meal (45%), fish oil (14%), wheat meal, and soya meal; and the commercial feed included fish meal (46%), fish oil (17%), soya meal, wheat meal, and corn gluten meal. The organic diet had higher amounts of vitamins A, C, and E; specific amino acids; and minerals that enhanced the biosynthesis of collagen. This study shows that fish fed the organic feed had significantly bigger collagen fibril diameters than the fish fed the conventional feed. Furthermore, the organically fed fish had similarly sized collagen fibril diameters as wild fish. More research is needed to understand the long-term effects and the mechanism and function of fish collagen peptide intake on lipid absorption and metabolism; and to identify dietary regimes that are able to improve whole body lipid profiles and suppress the transient increase of plasma triglycerides. Panagiotis Berillis, Eleni Mente, and Ioannis Nengas Copyright © 2011 Panagiotis Berillis et al. All rights reserved. Trend in Ambient Ozone and an Attempt to Detect Its Effect on Biota in Forest Ecosystem. Step I of Lithuanian Studies Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/419034/abs/ The presented study aimed to explore the relationships between ambient ozone (O3) and tree defoliation, specific diversity, and abundance of soil microarthropods, stream macroinvertebrates, and small mammals (mainly rodents) in order to test the hypothesis that changes in the considered objects of the forest ecosystem could be related to changes in ambient O3, concentration of which is below critical level. The observations were carried out from 1994 at three integrated monitoring stations. The obtained data revealed that only peak O3 concentrations (from 125–215 μg·m-3) had significant effect on changes in the considered components of forest biota. Algirdas Augustaitis, Ingrida Augustaitiene, Almantas Kliucius, Gintautas Mozgeris, Gintaras Pivoras, Rasele Girgzdiene, Kestutis Arbaciauskas, Irena Eitminaviciute, and Reda Mazeikyte Copyright © 2007 Algirdas Augustaitis et al. All rights reserved. Scientific and Societal Considerations in Selecting Assessment Endpoints for Environmental Decision Making Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/476959/abs/ It is sometimes argued that, from an ecological point of view, population-, community-, and ecosystem-level endpoints are more relevant than individual-level endpoints for assessing the risks posed by human activities to the sustainability of natural resources. Yet society values amenities provided by natural resources that are not necessarily evaluated or protected by assessment tools that focus on higher levels of biological organization. For example, human-caused stressors can adversely affect recreational opportunities that are valued by society even in the absence of detectable population-level reductions in biota. If protective measures are not initiated until effects at higher levels of biological organization are apparent, natural resources that are ecologically important or highly valued by the public may not be adequately protected. Thus, environmental decision makers should consider both scientific and societal factors in selecting endpoints for ecological risk assessments. At the same time, it is important to clearly distinguish the role of scientists, which is to evaluate ecological effects, from the role of policy makers, which is to determine how to address the uncertainty in scientific assessment in making environmental decisions and to judge what effects are adverse based on societal values and policy goals. Elizabeth M. Strange, Joshua Lipton, Douglas Beltman, and Blaine D. Snyder Copyright © 2002 Elizabeth M. Strange et al. All rights reserved. Determining Arsenic Distribution in Urban Soils: A Comparison with Nonurban Soils Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/478010/abs/ There are many challenges in the determination of arsenic background concentrations in soils. However, these challenges are magnified when those determinations are carried out on urban soils. Irrespective of this, it is important to correctly identify and understand the extent of pollution in order to provide efficient preventative, remedial actions and cost-effective management of contaminated areas. This review paper discusses the factors that make the determination of arsenic background concentrations in urban areas different from similar determinations in nonurban areas. It also proposes solutions, where applicable, that are based on experience in determining arsenic background concentrations in both urban and nonurban areas in Florida, and from other studies in the literature. Urban soils are considerably different from nonurban areas because they have significant human disturbance, making them more difficult to study. They are characterized by high spatial and temporal variability, compaction, and modified chemical and physical characteristics. These differences have to be addressed during site selection, sample collection, and statistical analyses when determining arsenic distribution. Tait Chirenje, L.Q. Ma, and E.J. Zillioux Copyright © 2002 Tait Chirenje et al. All rights reserved. Chronic vs. Short-Term Acute O3 Exposure Effects on Nocturnal Transpiration in Two Californian Oaks Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/481957/abs/ We tested the effect of daytime chronic moderate ozone (O3) exposure, short-term acute exposure, and both chronic and acute O3 exposure combined on nocturnal transpiration in California black oak and blue oak seedlings. Chronic O3 exposure (70 ppb for 8 h/day) was implemented in open-top chambers for either 1 month (California black oak) or 2 months (blue oak). Acute O3 exposure (~1 h in duration during the day, 120–220 ppb) was implemented in a novel gas exchange system that supplied and maintained known O3 concentrations to a leaf cuvette. When exposed to chronic daytime O3 exposure, both oaks exhibited increased nocturnal transpiration (without concurrent O3 exposure) relative to unexposed control leaves (1.8× and 1.6×, black and blue oak, respectively). Short-term acute and chronic O3 exposure did not further increase nocturnal transpiration in either species. In blue oak previously unexposed to O3, short-term acute O3 exposure significantly enhanced nocturnal transpiration (2.0×) relative to leaves unexposed to O3. California black oak was unresponsive to (only) short-term acute O3 exposure. Daytime chronic and/or acute O3 exposures can increase foliar water loss at night in deciduous oak seedlings. N. E. Grulke, E. Paoletti, and R. L. Heath Copyright © 2007 N. E. Grulke et al. All rights reserved. Proposed Methods and Endpoints for Defining and Assessing Adverse Environmental Impact (AEI) on Fish Communities/Populations in Tennessee River Reservoirs Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/515323/abs/ Two multimetric indices have been developed to help address fish community (reservoir fish assemblage index [RFAI]) and individual population quality (sport fishing index [SFI]) in Tennessee River reservoirs. The RFAI, with characteristics similar to the index of biotic integrity (IBI) used in stream fish community determinations, was developed to monitor the existing condition of resident fish communities[1,2,3]. The index, which incorporates standardized electrofishing of littoral areas and experimental gill netting for limnetic bottom-dwelling species, has been used to determine residential fish community response to various anthropogenic impacts in southeastern reservoirs. Gary D. Hickman and Mary L. Brown Copyright © 2002 Gary D. Hickman and Mary L. Brown. All rights reserved. Export of Dissolved Organic Carbon from a Ponded Freshwater Marsh Receiving Diverted Mississippi River Water Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/368062/ A series of diversion projects has been implemented to reintroduce Mississippi River water into Louisiana's coastal wetlands in order to reduce wetland loss. The export of dissolved organic carbon (DOC) was measured in a 3,700-ha ponded freshwater marsh that receives diverted Mississippi River water. Results show that highly organic marsh soil and plant material are a source of DOC. DOC, on average, was 3 mg/l greater in outlet water as compared to the concentration in river water entering the wetland. DOC in water leaving the marsh was higher in summer months, with a concentration up to 18 mg/l. Based on a discharge of 1,000 ft3/sec (28.3 m3/sec), it was estimated that the equivalent of 7,335 kg/day of DOC would be exported from the marsh into Lake Cataouatche, located in the northern portion of the Louisiana Barataria Basin estuary. Results suggest that river diversion would likely increase the export of DOC from the marsh as compared to normal transport associated with rainfall and tidal exchange. R. D. DeLaune, C. B. Johnson, R. P. Gambrell, and A. Jugsujinda Copyright © 2008 R. D. DeLaune et al. All rights reserved. Linking Increasing Drought Stress to Scots Pine Mortality and Bark Beetle Infestations Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/369535/abs/ In the dry Swiss Rhone Valley, Scots pine forests have experienced increased mortality in recent years. It has commonly been assumed that drought events and bark beetles fostered the decline, however, whether bark beetle outbreaks increased in recent years and whether they can be linked to drought stress or increasing temperature has never been studied. Matthias Dobbertin, Beat Wermelinger, Christof Bigler, Matthias Bürgi, Mathias Carron, Beat Forster, Urs Gimmi, and Andreas Rigling Copyright © 2007 Matthias Dobbertin et al. All rights reserved. Artichoke Cultivars (var. “Blanca de Tudela”) under Elevated Ozone Concentrations Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/374082/abs/ Ozone concentrations rise to phytotoxic levels from spring to autumn at western Mediterranean basin coastal sites, where artichoke is one of the most important crops. Simultaneously, from year to year and especially since the early 1980s, resprouting of the stumps has been decreasing in Valencian Community artichoke plantations. To see if ozone might be playing a role in this decrease, a number of plants were exposed to different levels of ozone. Results of the ozone treatments showed reduced biomass in the offshoots of plants exposed to the highest ozone treatment. The exposure to ambient ozone during the stump-establishment period, when compared to filtered-air conditions, resulted in a reduction in yield when plants were transplanted in the field under ambient ozone concentrations. And when plants were exposed to acute short picks, typical ozone visual injury appeared in the older leaves. M.J. Sanz, J.L. Porcuna, E. Calvo, and C. Martin Copyright © 2002 M.J. Sanz et al. All rights reserved. Metamorphosis of Benthic Invertebrate Larvae: A Sensitive Indicator for Detection of Changes in Marine Environmental Quality Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/378464/abs/ Many marine coastal ecosystems are threatened by increasing waste discharge, and bioassays are needed because chemical and physical tests alone are not sufficient to assess potential effects on aquatic biota. In light of the fact that larval metamorphosis of benthic invertebrates is usually very sensitive to environmental changes, this paper reviews sensitivity comparisons of larval metamorphosis with other common bioassays in different species and those in different developmental stages of the same species, and it discusses the potential use of larval metamorphosis as an indicator of marine environmental quality. Xuelei Zhang Copyright © 2002 Xuelei�Zhang. All rights reserved. Effects of Brash Removal After Clear Felling on Soil and Soil-Solution Chemistry and Field-Layer Biomass in an Experimental Nitrogen Gradient Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/387013/abs/ Biofuels, such as brash from forest fellings, have been proposed as an alternative energy source. Brash removal may affect the sustainability of forest production, e.g., through a change in the availability of cations and N in the soil. We report initial effects of brash removal on inorganic N content in humus and mineral soil, soil-solution chemistry, and field-layer biomass after clear felling an N-fertilisation experiment in central Sweden. The experiment comprised six different fertiliser levels, ranging from 0 to 600 kg N ha�1. Urea was given every 5th year during 1967 to 1982 to replicated plots, giving total doses of 0 to 2400 kg N ha�1. Clear felling took place in 1995, 13 years after the last fertilisation. The removal of brash decreased the NO3� content in the humus layer after clear felling. A decrease in the NO3� concentration of the soil solution was indicated during most of the study period as well. No effect of the previous N fertilisation was found in the humus layer, but in the mineral soil there was an increase in NO3� content for the highest N dose after clear felling (p = 0.06). The soil-solution chemistry and the field-layer biomass showed an irregular pattern with no consistent effects of brash removal or previous fertilisation. E. Ring, L. Hogbom, and H.A. Nohrstedt Copyright © 2001 E. Ring et al. All rights reserved. Recent Trends in the Development of Ecological Models Applied on Aquatic Ecosystems Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/358369/abs/ This paper presents an overview of the application of models on aquatic ecosystems. More than 17% of the models published in the focal journal in the field, Ecological Modelling, are aquatic ecosystem models. An increasing number of papers are dealing with the theoretical aspects of modeling – new modeling approaches and techniques, how models can be used to reveal ecosystem properties, and how models can better reflect the properties of ecosystems. This development implies that today we have more types of models. The characteristics, the advantages, and the disadvantages of these model types are presented briefly. The selection criteria for the presented model types are discussed, and the application of these types to models for aquatic ecosystems is reviewed. A recent improvement in model calibration of particular interest for aquatic ecosystems is presented, and the perspectives resulting from this new calibration procedure and from possible hybrids of the presented model types are discussed. S.E. Jorgensen Copyright © 2002 S.E. Jorgensen. All rights reserved. The Impact of Long-Term Nitrogen Addition on Microbial Community Composition in Three Hawaiian Forest Soils Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/361739/abs/ We evaluated the microbial communities in three Hawaiian forest soils along a natural fertility gradient and compared their distinct responses to long-term nitrogen (N) additions. The sites studied have the same elevation, climate, and dominant vegetation, but vary in age of development, and thus in soil nutrient availability and nutrient limitation to plant growth. Fertilized plots at each site have received 100 kg ha year-1 N addition for at least 8 years. Soil parameters, water content, pH, and ammonium and nitrate availability differed by site, but not between control and N-addition treatments within a site at the time of sampling. Microbial biomass also varied by site, but was not affected by N addition. In contrast, microbial community composition (measured by phospholipid analysis) varied among sites and between control and N-addition plots within a site. These data suggest that microbial community composition responds to N addition even when plant net primary productivity is limited by nutrients other than N. This may have implications for the behavior of forests impacted by atmospheric N deposition that are considered to be “nitrogen saturated,” yet still retain N in the soil. Teri C. Balser Copyright © 2001 Teri C. Balser. All rights reserved. A Review of Nontraditional Biomanipulation Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/362037/ The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels. Xia Zhang, Ping Xie, and Xiaoping Huang Copyright © 2008 Xia Zhang et al. All rights reserved. An Innovative Approach for Locating and Evaluating Subsurface Pathways for Nitrogen Loss Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/304197/abs/ Fundamental watershed-scale processes governing chemical flux to neighboring ecosystems are so poorly understood that effective strategies for mitigating chemical contamination cannot be formulated. Characterization of evapotranspiration, surface runoff, plant uptake, subsurface preferential flow, behavior of the chemicals in neighboring ecosystems, and an understanding of how crop management practices influence these processes are needed. Adequate characterization of subsurface flow has been especially difficult because conventional sampling methods are ineffective for measuring preferential flow of water and solutes. A sampling strategy based on ground-penetrating radar (GPR) mapping of subsurface structures coupled with near real-time soil moisture data, surface topography, remotely sensed imagery, and a geographic information system (GIS) appears to offer a means of accurately identifying subsurface preferential flow pathways. Four small adjacent watersheds draining into a riparian wetland and first-order stream at the USDA-ARS Beltsville Agricultural Research Center, Beltsville, MD are being studied with this protocol. The spatial location of some preferential flow pathways for chemicals exiting these agricultural watersheds to the neighboring ecosystems have been identified. Confirmation of the pathways is via examination of patterns in yield monitor data and remote sensing imagery. C.L. Walthall, T.J. Gish, C.S.T. Daughtry, W.P. Dulaney, K.-J.S. Kung, G. McCarty, D. Timlin, J. T. Angier, P. Buss, and P. R. Houser Copyright © 2001 C.L. Walthall et al. All rights reserved. Estimated Historical and Current Nitrogen Balances for Illinois Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/252987/abs/ The Midwest has large riverine exports of nitrogen (N), with the largest flux per unit area to the Mississippi River system coming from Iowa and Illinois. We used historic and current data to estimate N inputs, outputs, and transformations for Illinois where human activity (principally agriculture and associated landscape drainage) have had a dominant impact. Presently, ~800,000 Mg of N is added each year as fertilizer and another 420,000 Mg is biologically fixed, primarily by soybean (Glycine max L. Merr.). These annual inputs are greater than exports in grain, which results in surplus N throughout the landscape. Rivers within the state export approximately 50% of this surplus N, mostly as nitrate, and the remainder appears to be denitrified or temporarily incorporated into the soil organic matter pool. The magnitude of N losses for 1880, 1910, 1950, and 1990 are compared. Initial cultivation of the prairies released large quantities of N (~500,000 Mg N year�1), and resulted in riverine N transport during the late 19th century that appears to have been on the same order of magnitude as contemporary N losses. Riverine flux was estimated to have been at a minimum in about 1950, due to diminished net mineralization and low fertilizer inputs. Residual fertilizer N from corn (Zea mays L.), biological N fixed by soybean, short-circuiting of soil water through artificial drainage, and decreased cropping-system diversity appear to be the primary sources for current N export. Mark B. David, Gregory F. McIsaac, Todd V. Royer, Robert G. Darmody, and Lowell E. Gentry Copyright © 2001 Mark B. David et al. All rights reserved. Nitrogen and the Baltic Sea: Managing Nitrogen in Relation to Phosphorus Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/319865/abs/ The Baltic is a large, brackish sea (4 x 105 km2) extending from 54ÅN to ~66ÅN, with a fourfold larger drainage area (population 8 x 107). Surface salinity (2 to 8 PSU) and hence biodiversity is low. In the last century, annual nutrient loads increased to 106 metric tons N and 5 x104 ton P. Eutrophication is evident in the N-limited south, where cyanobacteria fix 2 to 4 x 105 ton N each summer, Secchi depths have been halved, and O2-deficient bottom areas have spread. Production remains low in the P-limited north. In nutrient-enriched coastal areas, phytoplankton blooms, toxic at times, and filamentous macroalgae reduce amenity values. Loads need to be reduced of both N, to reduce production, and P, to limit N-fixing cyanobacterial blooms. When large N-load reductions have been achieved locally, algal biomass has declined. So far, P loads have been reduced more than N loads. If this continues, a P-limited Baltic proper may result, very different from previous N-limited conditions. Reaching the management goal of halved anthropogenic N and P loads at minimum cost will require better understanding of biogeochemical nutrient cycles, economic evaluation of proposed measures, and improved stakeholder participation. R. Elmgren and U. Larsson Copyright © 2001 R. Elmgren and U. Larsson. All rights reserved. Optimizing Nitrogen Management in Food and Energy Production and Environmental Protection: Summary Statement from the Second International Nitrogen Conference Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/320976/abs/ Human efforts to produce food and energy are changing the nitrogen (N) cycle of the Earth. Many of these changes are highly beneficial for humans, while others are detrimental to people and the environment. These changes transcend scientific disciplines, geographical boundaries, and political structures. They challenge the creative minds of natural and social scientists, economists, engineers, business leaders, and decision makers. The Second International Nitrogen Conference was designed to facilitate communications among all stakeholders in the “nitrogen community” of the world. The Conference participants’ goal in the years and decades ahead is to encourage every country to make optimal choices about N management in food production and consumption, energy production and use, and environmental protection. Scientific findings and recommendations for decision makers that emerged from the Conference are presented. Ellis Cowling, James Galloway, Cari Furiness, Mary Barber, Ton Bresser, Ken Cassman, Jan Willem Erisman, Richard Haeuber, Robert Howarth, Jerry Melillo, William Moomaw, Arvin Mosier, Kaj Sanders, Sybil Seitzinger, Stan Smeulders, Robert Socolow, Daniel Walters, Ford West, and Zhaoliang Zhu Copyright © 2001 Ellis Cowling et al. All rights reserved. Patterns in Abundance and Seasonality of Insects in the Siruvani Forest of Western Ghats, Nilgiri Biosphere Reserve, Southern India Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2004/408128/abs/ The seasonal abundance patterns of insects inhabiting the understory vegetation of a mixed deciduous forest were examined with the help of the sweep-net sampling method. During the study period of 2 years, insects were sampled regularly from the understory vegetation of the three selected habitats (moist-deciduous, riverine, and teak plantation) of the mixed deciduous forest. Insect abundance was maximum in the moist-deciduous habitat and minimum in the teak plantation. Generally, insect abundance was the highest during the southwest monsoon in all habitats. The temporal pattern of fluctuations in the insect abundance followed more or less the same pattern in all the three habitats studied. The insect abundance of the understory vegetation varied among the habitats studied, while the pattern of seasonal fluctuations in insect abundance was comparable among habitats. Composition of the insect community also indicated prominent seasonal changes within habitats than interhabitat changes within a season. P. R. Arun and V. S. Vijayan Copyright © 2004 P. R. Arun and V. S. Vijayan. All rights reserved. Prediction of Microcystis Blooms Based on TN:TP Ratio and Lake Origin Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/346710/ We evaluated the relationship between TN:TP ratio and Microcystis growth via a database that includes worldwide lakes based on four types of lake origin (dammed, tectonic, coastal, and volcanic lakes). We used microcosm and mesocosm for the nutrient elution tests with lake water and four kinds of sediment (nontreated, MgO sprinkling treated, dissolved air flotation [DAF] treated, and combined treated sediment) in order to control TN:TP ratio and to suppress Microcystis growth. Microcystis growth was related to TN:TP ratio, with the maximum value at an optimum TN:TP ratio and the minimum values when the TN:TP ratios reached to 0 or ∞. The kurtosis of the distribution curve varied with the type of lake origin; the lowest kurtosis was found in dammed lakes, while the highest was found in volcanic lakes. The lake trophic state could affect the change in the kurtosis, providing much lower kurtosis at eutrophic lakes (dammed lakes) than that at oligotrophic lakes (volcanic lakes). The relationship between TN:TP ratio and Microcystis growth could be explained by the nutrient elution tests under controlled TN:TP ratios through the various sediment treatments. A significant suppression of Microcystis growth of 70% could be achieved when the TN:TP ratios exceeded 21. Lake origin could be regarded as an index including morphological and geographical factors, and controlling the trophic state in lakes. The origin rather than trophic state for lakes could be considered as an important factor of TN:TP influences on Microcystis growth. Yoshimasa Amano, Motoi Machida, Hideki Tatsumoto, Dennis George, Sharon Berk, and Kazuo Taki Copyright © 2008 Yoshimasa Amano et al. All rights reserved. Induction of Glutathione Synthesis and Glutathione Reductase Activity by Abiotic Stresses in Maize and Wheat Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/394304/abs/ The effect of different abiotic stresses (extreme temperatures and osmotic stress) on the synthesis of glutathione and hydroxymethylglutathione, on the ratio of the reduced to oxidised forms of these thiols (GSH/GSSG, hmGSH/hmGSSG), and on the glutathione reductase (GR) activity was studied in maize and wheat genotypes having different sensitivity to low temperature stress. Cold treatment induced a greater increase in total glutathione (TG) content and in GR activity in tolerant genotypes of both species than in sensitive ones. The GSH/GSSG and hmGSH/hmGSSG ratios were increased by this treatment only in the frost-tolerant wheat variety. High-temperature stress increased the TG content and the GSH/GSSG ratio only in the chilling-sensitive maize genotype, but GR activity was greater after this treatment in both maize genotypes. Osmotic stress resulted in a great increase in the TG content in wheat and the GR activity in maize. The amount of total hydroxymethylglutathione increased following all stress treatments. These results indicate the involvement of these antioxidants in the stress responses of wheat and maize. Gábor Kocsy, Gabriella Szalai, and Gabor Gáliba Copyright © 2002 Gabor Kocsy et al. All rights reserved. Anthropogenic Effects on Forest Ecosystems at Various Spatio-Temporal Scales Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/396905/abs/ The focus in this review of long-term effects on forest ecosystems is on human impact. As a classification of this differentiated and complex matter, three domains of long-term effects with different scales in space and time are distinguished: 1- Exploitation and conversion history of forests in areas of extended human settlement 2- Long-range air pollution and acid deposition in industrialized regions 3- Current global loss of forests and soil degradation. Michael Bredemeier Copyright © 2002 Michael Bredemeier. All rights reserved. Migration and Enrichment of Arsenic in the Rock-Soil-Crop Plant System in Areas Covered with Black Shale, Korea Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2003/428492/abs/ The Okchon black shale, which is part of the Guryongsan Formation or the Changri Formation of Cambro-Ordovician age in Korea provides a typical example of natural geological materials enriched with potentially toxic elements such as U, V, Mo, As, Se, Cd, and Zn. In this study, the Dukpyung and the Chubu areas were selected to investigate the migration and enrichment of As and other toxic elements in soils and crop plants in areas covered with black shale. Rock and soil samples digested in 4-acid solution (HCl+HNO3+HF+HClO4) were analyzed for As and other heavy metals by ICP-AES and ICP-MS, and plant samples by INAA. Mean concentration of As in Okchon black shale is higher than those of both world average values of shale and black shale. Especially high concentration of 23.2 mg As kg-1 is found in black shale from the Dukpyung area. Mean concentration of As is highly elevated in agricultural soils from the Dukpyung (28.2 mg kg-1) and the Chubu areas (32.6 mg kg-1). As is highly elevated in rice leaves from the Dukpyung (1.14 mg kg-1) and the Chubu areas (1.35 mg kg-1). The biological absorption coefficient (BAC) of As in plant species decreases in the order of rice leaves > corn leaves > red pepper = soybean leaves = sesame leaves > corn stalks > corn grains. This indicates that leafy plants tend to accumulate As from soil to a greater degree than cereal products such as grains. Ji-Min Yi, Hyo-Taek Chon, and Min Park Copyright © 2003 Ji-Min Yi et al. All rights reserved. Complex Analyses of Plankton Structure and Function Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/428592/abs/ This paper critically evaluates some complex methods that have been used to characterize the structure and function of freshwater plankton communities. The focus is on methods related to plankton size structure and carbon transfer. The specific methods reviewed are 1) size spectrum analysis, 2) size-fractionated phytoplankton productivity, 3) size-fractionated zooplankton grazing, 4) plankton ecological transfer efficiency, and 5) grazer effects on phytoplankton community structure. Taken together, these methods can provide information on community ecological properties that are directly related to practical issues including water quality and fisheries productivity. However, caution is warranted since application without a complete understanding of assumptions and context of the manipulations could lead to erroneous conclusions. As an example, experimental studies involving the addition or removal of zooplankton, especially when coupled with nutrient addition treatments, could provide information on the degree of consumer vs. resource control of phytoplankton. Resource managers subsequently could use this information in developing effective measures for controlling nuisance algal biomass. However, the experiments must be done critically and with sufficient safeguards and other measurements to ensure that treatments (e.g., zooplankton exclosure by screening of water) actually are successful and do not introduce other changes in the community (e.g., removal of large algae). In all of the methods described here, the investigator must take care when generalizing results and, in particular, carry out a sufficient number of replications to encompass both the major seasonal and spatial variation that occurs in the ecosystem. Karl E. Havens Copyright © 2001 Karl E. Havens. All rights reserved. Downstream Effects of a Hydroelectric Reservoir on Aquatic Plant Assemblages Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/432842/abs/ Macrophytes were studied downstream of the Rophémel hydroelectric dam on the River Rance (Côtes d’Armor Department, western France) to assess the effects of hydroelectric functioning on river macrophyte communities. We studied ten representative sections of the hydro-peaking channel on five occasions in 1995 and 1996, on a 15-km stretch of river. Floristic surveys were carried out on sections 50 m in length, and genera of macroalgae, species of bryophyta, hydrophytes, and emergent rhizophytes were identified. For the aquatic bryophytes and spermatophytes section of our study, we compared our results with 19th century floristic surveys, before the dam was built. During the vegetative growth period, the hydro-peaking frequency was low. The plant richness was highest near the dam. The macrophyte communities were highly modified according to the distance to the dam. The frequency and magnitude of hydro-peaking was related to the aquatic macrophyte richness in an Intermediate Disturbance Hypothesis position. However, the results of the eco-historical comparison with 19th century floristic surveys point to the original nature of the flora found at the site. Some floral patterns, seen during both periods and at an interval of 133 years, were indicative of the ubiquity of the aquatic flora and of the plants’ adaptability. This demonstrates the importance of taking river basin history into account in such biological surveys. Ivan Bernez, Jacques Haury, and Maria Teresa Ferreira Copyright © 2002 Ivan Bernez et al. All rights reserved. Patterns of Understory Diversity in Mixed Coniferous Forests of Southern California Impacted by Air Pollution Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/460587/abs/ The forests of the San Bernardino Mountains have been subject to ozone and nitrogen (N) deposition for some 60 years. Much work has been done to assess the impacts of these pollutants on trees, but little is known about how the diverse understory flora has fared. Understory vegetation has declined in diversity in response to elevated N in the eastern U.S. and Europe. Six sites along an ozone and N deposition gradient that had been part of a long-term study on response of plants to air pollution beginning in 1973 were resampled in 2003. Historic ozone data and leaf injury scores confirmed the gradient. Present-day ozone levels were almost half of these, and recent atmospheric N pollution concentrations confirmed the continued air pollution gradient. Both total and extractable soil N were higher in sites on the western end of the gradient closer to the urban source of pollution, pH was lower, and soil carbon (C) and litter were higher. The gradient also had decreasing precipitation and increasing elevation from west to east. However, the dominant tree species were the same across the gradient. Edith B. Allen, Patrick J. Temple, Andrzej Bytnerowicz, Michael J. Arbaugh, Abby G. Sirulnik, and Leela E. Rao Copyright © 2007 Edith B. Allen et al. All rights reserved. Genotypic Effects of Fertilization on Seedling Sweetgum Biomass Allocation, N Uptake, and N Use Efficiency Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/463482/abs/ Screening and selecting tree genotypes that are responsive to N additions and that have high nutrient use efficiencies can provide better genetic material for short-rotation plantation establishment. A pot experiment was conducted to test the hypotheses that (1) sweetgum (Liquidambar styraciflua L.) families have different patterns in biomass production and allocation, N uptake, and N use efficiency (NUE), because of their differences in growth strategies, and (2) sweetgum families that are more responsive to N additions will also have greater nutrient use efficiencies. Seedlings from two half-sib families (F10022 and F10023) that were known to have contrasting responses to fertility and other stress treatments were used for an experiment with two levels of N (0 vs. 100 kg N/ha equivalent) and two levels of P (0 vs. 50 kg P/ha equivalent) in a split-plot design. Sweetgum seedlings responded to N and P treatments rapidly, with increases in both size and biomass production, and those responses were greater with F10023 than with F10022. Growth response to N application was particularly strong. N and P application increased the proportional allocation of biomass to leaves. Under increased N supply, P application increased foliar N concentration and content, as well as total N uptake by the seedlings. However, NUE was decreased by N addition and was higher in F10023 than in F10022 when P was not limiting. A better understanding of genotype by fertility interactions is important in selecting genotypes for specific site conditions and for optimizing nutrient use in forestry production. Scott X. Chang and Daniel J. Robison Copyright © 2001 Scott X. Chang and Daniel J. Robison. All rights reserved. Economic Analysis of Sequestering Carbon in Green Ash Forests in the Lower Mississippi River Valley Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2003/465379/abs/ Since the U.S. is the largest emitter of carbon dioxide (CO2), it has become crucial to develop options that are both cost effective and supportive of sustainable development to reduce atmospheric CO2. Electric utility companies have the options of reducing their use of fossil fuels, switching to alternative energy sources, increasing efficiency, or offsetting carbon emissions. This study determined the cost and profitability of sequestering carbon in green ash plantations, and the number of tons of carbon that can be sequestered. The profitability of green ash is $2,342 and $3,645 per acre on site indices (measurement of soil quality) 65 and 105 land, respectively, calculated with a 2.5% alternative rate of return (ARR). These figures shift to –$248 and –$240 calculated with a 15.0% ARR. If landowners who have an ARR of 2.5% can sell carbon credits for $10 per ton of carbon, profits will increase by $107 per acre on poor sites and $242 on good sites. Over one rotation (cutting cycle), 38.56 net tons of carbon can be sequestered on an acre of poor quality land and 51.35 tons on good quality land. The cost of sequestering carbon, without including revenues from timber production and carbon credits, ranges from a high of $15.20 per ton on poor sites to $14.41 on good sites, calculated with a 2.5% ARR; to a high of $8.51 per ton on poor sites to $7.63 on good sites, calculated with a 15.0% ARR. The cost of storing carbon can be reduced significantly if the trees can be sold for wood products. Ching-Hsun Huang, Gary D. Kronrad, and Shiaolin D. Cheng Copyright © 2003 Ching-Hsun Huang et al. All rights reserved. Degree of Phosphorus Saturation and Soil Phosphorus Thresholds in an Ultisol Amended with Triple Superphosphate and Phosphate Rocks Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2011/264701/ Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR), plus or minus manure. P release was determined by the iron oxide—impregnated paper strip (strip P), while DPS was determined from ammonium oxalate—extractable aluminum (Al), iron (Fe), and P. Soils were sampled from a closed incubation study involving soils treated with TSP, GPR, and CIPR at 0–400 mg P kg-1, and a field study where soils were fertilized with the same P sources at 100–300 kg P ha-1 plus or minus manure. The DPS was significantly influenced by P source x P rate, P source x manure (incubated soils), and by P source x P rate x time (field-sampled soils). Incubated soil results indicated that both initial P and total strip P were related to DPS by exponential functions: initial strip P = 1.38exp0.18DPS, R2 = 0.82** and total strip P = 8.01exp0.13DPS, R2 = 0.65**. Initial strip P was linearly related to total P; total P = 2.45, initial P + 8.41, R2 = 0.85**. The threshold DPS value established was about 22% (incubated soil). Field soils had lower DPS values <12% and strip P was related to initial DPS and average DPS in exponential functions: strip P = 2.6exp0.44DPS, R2 = 0.77** and strip P = 1.1DPS2 — 2.4DPS + 6.2, R2 = 0.58**, respectively. The threshold values were both at ≈8% and P release was 11–14 mg P kg-1. Results are evident that DPS can be used to predict P release, but the threshold values are environmentally sensitive; hence, recommendations should be based on field trials. E. W. Gikonyo, A. R. Zaharah, M. M. Hanafi, and A. R. Anuar Copyright © 2011 Esther W. Gikonyo et al. All rights reserved. Techniques of Ozone Monitoring in a Mountain Forest Region: Passive and Continuous Sampling, Vertical and Canopy Profiles Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/273598/abs/ Ozone is the most harmful air pollutant for plant ecosystems in the Mediterranean and Alpine areas due to its biological and economic damage to crops and forests. In order to evaluate the relation between ozone exposure and vegetation injury under on-field conditions, suitable ozone monitoring techniques were investi-gated. In the framework of a 5-year research project aimed at ozone risk assessment on forests, both continuous analysers and passive samplers were employed during the summer seasons (1994�1998) in different sites of a wide mountain region (80 x 40 km2) on the southern slope of the European Alps. Continuous analysers allowed the recording of ozone hourly concentration means necessary both to calculate specific exposure indexes (such as AOT, SUM, W126) and to record daily time-courses. Passive samplers, even though supplied only weekly mean concentration values, made it possible to estimate the altitude concentration gradient useful to correct the altitude dependence of ozone concentrations to be inserted into exposure indexes. In-canopy ozone profiles were also determined by placing passive samplers at different heights inside the forest canopy. Vertical ozone soundings by means of tethered balloons (kytoons) allowed the measurement of the vertical concentration gradient above the forest canopy. They also revealed ozone reservoirs aloft and were useful to explain the ozone advection dynamic in mountain slopes where ground measurement proved to be inadequate. An intercomparison between passive (PASSAM, CH) and continuous measurements highlighted the necessity to accurately standardize all the exposure operations, particularly the pre- and postexposure conservation at cold temperature to avoid dye (DPE) activity. Advantages and disadvantages from each mentioned technique are discussed. Giacomo Gerosa, Cristina Mazzali, and Antonio Ballarin-Denti Copyright © 2001 Giacomo Gerosa et al. All rights reserved. Practical Success of Biomanipulation using Filter-Feeding Fish to Control Cyanobacteria Blooms: A Synthesis of Decades of Research and Application in a Subtropical Hypereutrophic Lake Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/276487/abs/ 337 Lake Donghu is a 32-km 2 shallow, subtropical lake near the Yangtze River (P.R. China) that has experienced dramatic changes in the past five decades. These changes include: (1) a trophic state change from mesotrophy to hypertrophy; (2) dense blooms of cyanobacteria during every summer from the 1970s to 1984; (3) a cessation of blooms starting in 1985, with no recurrence; and (4) an increase, coincident with bloom declines, in the production of silver and bighead carp (filter-feeders) by more than tenfold. There are several possible explanations for the disappearance of blooms, including changes in nutrient concentrations, increased zooplankton grazing, and increased grazing on algae by fish. The long-term data suggest that changes in nutrients or in zooplankton were not important, but that the remarkably increased fish densities might have played the key role. To test this hypothesis, in situ enclosure experiments were conducted in three years. The main conclusions are as follows: (1) an increased stocking of the lake with carp played a decisive role in the elimination of cyanobacteria blooms; (2) both silver and bighead carp can eliminate cyanobacteria blooms directly by grazing; (3) zooplankton cannot suppress the blooms; and (4) the lake still is vulnerable to the outbreak of blooms, should fish grazing decline. The critical biomass of carp is approximately 50 g m 3 . The results suggest the applicability of a new food-web manipulation (increased stocking with filter-feeding fish) for controlling cyanobacteria blooms in hypereutrophic lakes. The approach differs from traditional biomanipulation in Europe and North America, where piscivores are added to control planktivores, and this in turn increases zooplankton and decreases algae. The new biomanipulation method is being used or being tested to counteract cyanobacteria blooms in many Chinese lakes such as Lake Dianchi?Xie and Liu: Biomanipulation to Control Cyanobacteria TheScientificWorld (2001) 1, 337-356 in Yunnan Province, Lake Chaohu in Anhui Province, and Lake Taihu in Jiangsu Province. The method has great potential as an important component of an integrated approach to counteract cyanobacteria blooms, especially in lakes where nutrient inputs cannot be reduced sufficiently, and where zooplankton cannot effectively control phytoplankton production. Ping Xie and Jiankang Liu Copyright © 2001 Ping Xie and Jiankang Liu. All rights reserved. Temporal Changes in Nitrogen Pollution in Northeastern Estonia Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/281637/abs/ During the last 5 decades the northeastern part of Estonia (the region where oil shale and the chemical industry are located) has been subjected to pollution with acidic compounds. In 1981�1988 the yearly mean nitrogen (N) deposition load was up to 11.1 kg ha�1. This N pollution level combined with the deposition of sulphur (S) could have seriously endangered the environment, but the simultaneous emission of strongly alkaline fly ash restrained acidification processes. After 1989�1991 the situation changed, and in 1994�1996 the N deposition load in northeastern Estonia remained within the range of 2.6 to 6.6 kg ha�1 year�1 and that of S within 2 to 50 kg ha�1 year�1. Because the fly ash deposition is permanently decreasing, more sensitive lichens and mosses can be subjected to critical N+S loads in the future. The proportion of oil shale industry in total emission of NOx in Estonia from stationary sources equals approximately 65 to 75%. During 1996�2000 the yearly mean concentration of NO2 in the air of towns increased from 9 to 12 to 16 to 29��g�m�3. The emission of N compounds was mainly caused by N oxides in flue gases from power plants, as well as ammonia and carbamide discharges from chemical plants. In 1988�1990 the estimated yearly total emission of NOx (as NO2 equivalent) was about 18 to 18.6 thousand t and in 1994�2000, 9.9 to 11.8 thousand t. Valdo Liblik Copyright © 2001 Valdo�Liblik. All rights reserved. From Litterfall to Breakdown in Streams: A Review Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/180292/abs/ This paper is a review of recent (�10 years) information on litterfall, standing stock of benthic organic matter, breakdown rates, and fungal colonization of organic matter in streams. In some cases, recent research reinforces the findings of classic reference papers. In other cases, the additional knowledge provided by recent research introduces a higher variation in the processes analyzed. In many aspects, especially those concerning stream organic matter, the review is biased towards the temperate North American streams, reflecting the fact that most research was carried out there. However, during the 1990s European studies increased enormously, especially those related with instream processes, such as leaf litter decomposition. The first part of this review analyzes the origin of allochthonous organic matter to streams (litterfall, retention, and storage), and it provides data on the amounts estimated in different streams and on the methodology used in the studies. The second part analyzes the fate of detritus in streams: mechanisms of leaf breakdown, relative importance of fungi and bacteria, factors affecting the activity of microbial decomposers, and chemical changes of leaf litter during decomposition. A list of breakdown rates of several different leaf species is given, together with the methodology used, and the main characteristics of the incubation streams. Manuela Abelho Copyright © 2001 Manuela�Abelho. All rights reserved. Habitat Management: A Tool to Modify Ecosystem Impacts of Nitrogen Deposition? Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/182432/abs/ Atmospheric nitrogen deposition has been shown to affect both the structure and the function of heathland ecosystems. Heathlands are semi-natural habitats and, as such, undergo regular management by mowing or burning. Different forms of management remove more or less nutrients from the system, so habitat management has the potential to mitigate some of the effects of atmospheric deposition. Data from a dynamic vegetation model and two field experiments are presented. The first involves nitrogen addition following different forms of habitat management. The second tests the use of habitat management to promote heathland recovery after a reduction in nitrogen deposition. Both modelling and experimental approaches suggest that plant and microbial response to nitrogen is affected by management. Shoot growth and rates of decomposition were lowest in plots managed using more intensive techniques, including mowing with litter removal and a high temperature burn. Field data also indicate that ecosystem recovery from prolonged elevated inputs of nitrogen may take many years, or even decades, even after the removal of plant and litter nitrogen stores which accompanies the more intensive forms of habitat management. S.A. Power, C.G. Barker, E.A. Allchin, M.R. Ashmore, and J.N.B. Bell Copyright © 2001 S.A. Power et al. All rights reserved. Bermudagrass Management in the Southern Piedmont U.S. IV. Soil Surface Nitrogen Pools Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/187107/abs/ The fate of nitrogen (N) applied in forage-based agricultural systems is important for understanding the long-term production and environmental impacts of a particular management strategy. We evaluated the factorial combination of three types of N fertilization (inorganic, crimson clover [Trifolium incarnatum L.] cover crop plus inorganic, and chicken [Gallus gallus] broiler litter pressure and four types of harvest strategy (unharvested forage, low and high cattle [Bos Taurus] grazing pressure, and monthly haying in summer) on surface residue and soil N pools during the first 5 years of ̒Coastal̓ bermudagrass (Cynodon dactylon [L.] Pers.) management. The type of N fertilization used resulted in small changes in soil N pools, except at a depth of 0 to 2 cm, where total soil N was sequestered at a rate 0.2 g ‧ kg–1‧ year–11 greater with inorganic fertilization than with other fertilization strategies. We could account for more of the applied N under grazed systems (76–82%) than under ungrazed systems (35–71%). As a percentage of applied N, 32 and 48% were sequestered as total soil N at a depth of 0 to 6 cm when averaged across fertilization strategies under low and high grazing pressures, respectively, which was equivalent to 6.8 and 10.3 g ‧ m–2 ‧ year–1. Sequestration rates of total soil N under the unharvested-forage and haying strategies were negligible. Most of the increase in total soil N was at a depth of 0 to 2 cm and was due to changes in the particulate organic N (PON) pool. The greater cycling of applied N into the soil organic N pool with grazed compared with ungrazed systems suggests an increase in the long-term fertility of soil. Alan J. Franzluebbers and John A. Stuedemann Copyright © 2001 Alan J. Franzluebbers and John A. Stuedemann. All rights reserved. Functional Evaluations in the Monitoring of the River Ecosystem Processes: The Adige River as a Case Stu Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/187694/abs/ A model of analysis and environmental evaluation was applied to 11 stretches of the Adige River, where an innovative procedure was carried out to interpret ecological results. Within each stretch, the most suitable methods were used to assess the quality and processes of flood plains, banks, water column, bed, and interstitial environment. Indices were applied to evaluate the wild state and ecological quality of the banks (wild state index, buffer strip index) and the landscape quality of wide areas of the fluvial corridor (environmental landscape index). The biotic components (i.e., macrozoobenthos, phytoplankton and zooplankton, interstitial hyporheic fauna, vegetation in the riparian areas) were analysed by both quantitative and functional methods (as productivity, litter – processing and colonisation). The results achieved were then translated into five classes of functional evaluation. These qualitative assessments have thus preserved a high level of precision and sensitivity in quantifying both the quality of the environmental conditions and the integrity of the ecosystem processes. Read together with urban planning data, they indicate what actions are needed to restore and rehabilitate the Adige River corridor. M.G. Braioni, G. Salmoiraghi, F. Bracco, M. Villani, A. Braioni, and L. Girelli Copyright © 2002 M.G. Braioni et al. All rights reserved. Adverse Environmental Impact: A Consultant’s Perspective Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/191652/abs/ Environmental consultants are in a unique position to address the practical aspects of a working definition of “adverse environmental impact” (AEI) within Section 316(b) of the Clean Water Act. In our work with the electric utility industry, attorneys, and regulatory agencies, we have encountered numerous and sometimes conflicting interpretations as to what constitutes AEI. In our over 30 years of experience, we have applied most of the approaches suggested for addressing this issue, including biostatistical methods, trend analysis, time series methods, conditional mortality rate models, stock-recruitment models, equivalent adult models, and ecosystem models. In our experience, the paradigm most helpful in bringing about agreement among stakeholders is to (1) create a model of operating scenarios, (2) use empirical data from on-site studies to parameterize the model, (3) convert losses by life stage to equivalent adult losses, (4) convert equivalent adult losses to economic value, and (5) compare scenarios on an economic basis. Alan W. Wells and Thomas L. Englert Copyright © 2002 Alan W. Wells and Thomas L. Englert. All rights reserved. Contribution of Ambient Ozone to Changes in Scots Pine Defoliation. Step II of Lithuanian Studies Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/191780/abs/ This study aimed to explore if changes in peak ozone (O3) concentrations may reinforce the phytotoxic effects of air concentration of acidifying compounds and their deposition, as well as unfavorable climatic factors on pine crown defoliation. Forty-eight pine stands with more than 8000 sample pine trees have been monitored annually. The impact of sulfur dioxide (SO2) on pine defoliation was found to be the most significant. The impacts of peak O3 concentrations, acid deposition, and amount of precipitation were considerably lower, whereas the impact of air temperature, the least. Contribution of peak O3 concentrations to the integrated impact of acid deposition and amount of precipitation on pine defoliation was most significant, whereas the contribution to the impact of acidifying air compounds, mainly SO2, was the least. No synergetic effect between peak O3 concentrations and high temperature during vegetation period was detected. Algirdas Augustaitis, Ingrida Augustaitiene, Almantas Kliucius, Rasele Girgzdiene, and Dalia Sopauskiene Copyright © 2007 Algirdas Augustaitis et al. All rights reserved. Secondary Air Pollutants and Forests — New Perspectives Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/165917/abs/ Air pollution has been known to affect forests for over a century, and many of the mechanisms of pollutant deposition and effects have been established, at least for forest trees. Changes in air quality as a result of emission controls in Europe and North America, or as a result of rapid industrialisation in southern and eastern Asia, have highlighted new pollution problems. This paper, by reference to recent publications, highlights two areas where more research is required: the interactions of photochemical oxidants with biogenic emissions of volatile organic compounds, and their impact on ecological signalling; and the role of atmospheric particles in changing the leaf surface environments in forests. J. Neil Cape Copyright © 2007 J. Neil Cape. All rights reserved. Effects of Eucalyptus Plantations on Detritus, Decomposers, and Detritivores in Streams Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/193579/abs/ Vast areas of the Iberian Peninsula are covered by monocultures of the exotic tree Eucalyptus globulus. Given that (1) leaf litter produced in the riparian areas is the main energy source for small streams, and (2) trees differ in their nutrient content, chemical defenses, and physical attributes, eucalypt plantations have the potential to affect the biology of streams. Research teams from the University of Coimbra and the University of the Basque Country have been addressing the potential effects of eucalypt plantations at several levels of study. Here we review the main conclusions of these investigations. Manuel A.S. Graça, Jesus Pozo, Cristina Canhoto, and Arturo Elosegi Copyright © 2002 Manuel A.S. Graca et al. All rights reserved. Tissue Distribution and Depuration of the Extracted Hepatotoxic Cyanotoxin Microcystins in Crucian Carp (Carassius carassius) Intraperitoneally Injected at a Sublethal Dose Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/196085/ An acute toxicity experiment was conducted by intraperitoneal injection with a sublethal dose of extracted microcystins (MCs), 50 μg MC-LR (where L = leucine and R = arginine) equivalent/kg body weight (BW), to examine tissue distribution and depuration of MCs in crucian carp (Carassius carassius). Liver to body weight ratio increased at 3, 12, 24, and 48 h postinjection compared with that at 0 h (p < 0.05). MC concentrations in various tissues and aquaria water were analyzed at 1, 3, 12, 24, 48, and 168 h postinjection using liquid chromatography coupled with mass spectrometry (LC-MS). The highest concentration of MCs (MC-RR + MC-LR) was found in blood, 2–270 ng/g dry weight (DW), followed by heart (3–100 ng/g DW) and kidney (13–88 ng/g DW). MC levels were relatively low in liver, gonad, intestine, spleen, and brain. MC contents in gills, gallbladder, and muscle were below the limit of detection. Significant negative correlation was present between MC-RR concentration in blood and that in kidney, confirming that blood was important in the transportation of MC-RR to kidney for excretion. Rapid accumulation and slow degradation of MCs were observed in gonad, liver, intestine, spleen, and brain. Only 0.07% of injected MCs were detected in liver. The recovery of MCs in liver of crucian carp seemed to be dose dependent. Hehua Lei, Ping Xie, Jun Chen, Gaodao Liang, Ting Yu, and Yan Jiang Copyright © 2008 Hehua Lei et al. All rights reserved. Changes in the Essential Oil Composition in the Needles of Scots Pine (Pinus sylvestris L.) Under Anthropogenic Stress Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/125054/abs/ Unfavorable anthropogenic factors, such as air pollution, lead to biochemical responses in trees. Changes in the amounts of secondary metabolites may be early indicators of invisible injuries. The aim of this study was to evaluate composition of the essential oils in the needles of Scots pine (Pinus sylvestris L.) growing in the areas affected by pollutant emissions of main factories in Lithuania: a nitrogen fertilizer factory (NFF), a cement factory (CF), and an oil refinery (OR). Totally, 14 pine stands were examined along transects from the factories (July 2005). Volatile components of the needles were extracted and analyzed by GC and GC/MS. Over 70 components of the essential oils were identified in current-year and 1-year-old needles. Asta Judzentiene, Aida Stikliene, and Eugenija Kupcinskiene Copyright © 2007 Asta Judzentiene et al. All rights reserved. Best Management Practices for Minimizing Nitrate Leaching from Container-Grown Nurseries Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/102320/abs/ Containerized plant production represents an extremely intensive agricultural practice; 40,000 to 300,000 containers may occupy one acre of surface area to which a large amount of chemical fertilizer is applied. Currently, recommended fertilizer application rates for the production of containerized nursery ornamental plants are in excess of plant requirements, and up to 50% of the applied fertilizers may run off or be leached from containers. Among the nutrients leached or allowed to runoff, nitrogen (N) is the most abundant and is of major concern as the source of ground and surface water pollution. In this report, current N fertilizer application rates for different container-grown nursery ornamental plants, the amount of nitrate leaching or runoff from containers, and the potential for nitrate contamination of ground and surface water are discussed. In contrast, our best N management practices include: (1) applying fertilizers based on plant species need; (2) improving potting medium�s nutrient holding capacity using obscure mineral additives; (3) using controlled-release fertilizers; and (4) implementing zero runoff irrigation or fertigation delivery systems that significantly reduce nitrate leaching or runoff in containerized plant production and encourage dramatic changes in N management. Jianjun Chen, Yingfeng Huang, and Russell D. Caldwell Copyright © 2001 Jianjun Chen et al. All rights reserved. The International Editorship of Freshwater Systems Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/103786/abs/ Karl E. Havens Copyright © 2001 Karl E. Havens. All rights reserved. Piscivores, Trophic Cascades, and Lake Management Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/164156/abs/ The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing) that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores) and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high) represent classical 3- and 4-trophic level food webs. Ray W. Drenner and Ray K. David Hambright Copyright © 2002 Ray W. Drenner and Ray K. David Hambright. All rights reserved. Comparing Clean Water Act Section 316(b) Policy Options Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/126872/abs/ This paper develops a comparative framework for policy proposals involving fish protection and Section 316(b) of the Clean Water Act (CWA). Section 316(b) addresses the impingement and entrainment of fish by cooling-water intake structures used principally by steam electric power plants. The framework is motivated by examining the role of adverse environmental impacts (AEIs) in the context of Section 316(b) decision making. AEI is mentioned in Section 316(b), but not defined. While various AEI options have been proposed over the years, none has been formalized through environmental regulations nor universally accepted. Using a multiple values approach from decision analysis, AEIs are characterized as measurement criteria for ecological impacts. Criteria for evaluating AEI options are identified, including modeling and assessment issues, the characterization of ecological value, regulatory implementation, and the treatment of uncertainty. Motivated by the difficulties in defining AEI once and for all, a framework is introduced to compare options for 316(b) decision making. Three simplified policy options are considered, each with a different implicit or explicit AEI approach: (1) a technology-driven rule based on a strict reading of the 316(b) regulatory text, and for which any impingement and entrainment count as AEI, (2) a complementary, open-ended risk-assessment process for estimating population effects with AEI characterized on a site-specific basis, and (3) an intermediate position based on proxy measures such as specially constructed definitions of littoral zone, sensitive habitat, or water body type. The first two proposals correspond roughly to responses provided, respectively, by the Riverkeeper environmental organization and the Utility Water Act Group to the U.S. Environmental Protection Agency (EPA)’s proposed 316(b) new facilities rule of August 2000; the third example is a simplified form of the EPA’s proposed August 2000 new facilities rule itself. The simplified policy positions are compared using the three dimensions of the comparative policy framework: (1) the role of CWA philosophy or vision, such as the use of technology-forcing rules, (2) regulatory policy implementation, and (3) the role for scientific information and the knowledge base. Strengths and weaknesses of all three 316(b) policy approaches are identified. The U.S. EPA’s final new facilities rule of November 2001 is briefly characterized using the comparative policy framework and used to further illustrate the approach. John Kadvany Copyright © 2002 John Kadvany. All rights reserved. Forest Health Status in Europe Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/131070/abs/ Forest health status in Europe is assessed by the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). Established by the Convention on Long-Range Transboundary Air Pollution (CLRTAP) under the United Nations Economic Commission for Europe (UNECE), the ICP Forests has been monitoring forest condition in close cooperation with the European Commission (EC) for 20 years. The present paper describes the latest results of the deposition measurements on permanent monitoring plots and of the extensive defoliation sample survey. The findings reveal marked spatial patterns in bulk and throughfall depositions of nitrate (N-NO3-), ammonium (N-NH4+), and sulfate (S-SO42-), as well as an obvious decrease in bulk and throughfall deposition of sulfate. Latest analyses of defoliation data confirm previous results, indicating a high correlation with weather extremes. Martin Lorenz and Volker Mues Copyright © 2007 Martin Lorenz and Volker Mues. All rights reserved. Ozone in Spain's National Parks and Protected Forests Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/131924/abs/ In general, it is difficult to measure air pollutant concentrations in remote areas, as they are mostly national parks and protected areas. Passive samplers provide an accurate and inexpensive method for measuring cumulative exposures of different air pollutants. They have been used to collect ozone data in both laboratory and field at different geographical scales. The objective of the present study is to fill the knowledge gap regarding air quality in remote areas of Spain, such as national parks and protected areas. Because there were no systematic data sets on the main air pollutants that could affect these areas, an air quality measurement network was established between 2001 and 2004 on 19 locations inside Spanish national parks and protected areas. The data collected suggest that ozone levels in mountainous areas are high enough to affect sensitive vegetation. Most of the locations registered moderate-to-high ozone levels, with important interannual variability. Altitudinal ozone gradients were observed in most of the parks with complex topography due to the establishment of local circulations that incorporate polluted air masses from polluted airsheds or even long-range transport (i.e., Canary Islands). Different latitude-dependent, yearly cycles were also observed, showing two, one, or no clear peaks depending on the region. These findings extend to the most southerly locations, except in the Canary Islands, where pollution transported from other regions in the upper transport layers probably led to the high concentrations observed. María J. Sanz, Francisco Sanz, Vicent Calatayud, and Gerardo Sanchez-Peña Copyright © 2007 Mar?a J. Sanz et al. All rights reserved. Polychlorinated Alkanes in Fish from Norwegian Freshwater Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/139870/abs/ Short-chain polychlorinated alkanes (sPCAs) have been measured in freshwater fish samples from different lakes all over Norway and from the Norwegian Arctic. The analyses were performed with high-resolution GC coupled to high-resolution MS in electron capture negative ion mode. The species investigated were trout, Arctic char, and burbot (Lota lota). Muscle tissue in the lake trout and Arctic char, and liver in burbot, were selected for analyses because of their high lipid content. ∑sPCA concentration ranged from 108 to 3700 ng/g fat. The highest value was found in the south of Norway near an industrial area. Anders R. Borgen, Martin Schlabach, Roland Kallenborn, and Eirik Fjeld Copyright © 2002 Anders R. Borgen et al. All rights reserved. Seasonal Trophic Shift of Littoral Consumers in Eutrophic Lake Taihu (China) Revealed by a Two-Source Mixing Model Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2011/142520/ We evaluated the seasonal variation in the contributions of planktonic and benthic resources to 11 littoral predators in eutrophic Lake Taihu (China) from 2004 to 2005. Seasonal fluctuations in consumer σ13C and σ15N were attributed to the combined impacts of temporal variation in isotopic signatures of basal resources and the diet shift of fishes. Based on a two-end-member mixing model, all target consumers relied on energy sources from coupled benthic and planktonic pathways, but the predominant energy source for most species was highly variable across seasons, showing seasonal trophic shift of littoral consumers. Seasonality in energy mobilization of consumers focused on two aspects: (1) the species number of consumers that relied mainly on planktonic carbon showed the lowest values in the fall and the highest during spring/summer, and (2) most consumer species showed seasonal variation in the percentages of planktonic reliance. We concluded that seasonal trophic shifts of fishes and invertebrates were driven by phytoplankton production, but benthic resources were also important seasonally in supporting littoral consumers in Meiliang Bay. Energy mobilization of carnivorous fishes was more subject to the impact of resource availability than omnivorous species. Qiong Zhou, Ping Xie, Jun Xu, Xufang Liang, Jianhui Qin, Te Cao, and Feizhou Chen Copyright © 2011 Qiong Zhou et al. All rights reserved. Characterization of Pseudomonas Species Isolated from the Rhizosphere of Plants Grown in Serozem Soil, Semi-Arid Region of Uzbekistan Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2005/148947/abs/ Collections of native Pseudomonas spp. are kept at the NCAM of Uzbekistan. Some of those organisms were isolated from the rhizosphere of cotton, wheat, corn, melon, alfalfa, and tomato grown in field locations within a semi-arid region of Uzbekistan. Strains used for this study were Pseudomonas alcaligenes, P. aurantiaca, P. aureofaciens, P. denitrificans, P. mendocina, P. rathonis, and P. stutzeri. Some of the pseudomonads have been characterized in this report. These strains produced enzymes, phytohormone auxin (IAA), and were antagonist against plant pathogenic fungi in in vitro experiments. Most of the strains were salt tolerant and temperature resistant. Some of the Pseudomonas spp. isolated in this study have been found to increase the growth of wheat, corn, and tomato in pot experiments. Dilfuza Egamberdiyeva Copyright © 2005 Dilfuza Egamberdiyeva. All rights reserved. Shorebird Use of Coastal Wetland and Barrier Island Habitat in the Gulf of Mexico Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/154026/abs/ The Gulf Coast contains some of the most important shorebird habitats in North America. This area encompasses a diverse mixture of estuarine and barrier island habitats with varying amounts of freshwater swamps and marshes, bottomland hardwood forests, and coastal prairie that has been largely altered for rice and crawfish production, temporary ponds, and river floodplain habitat. For the purposes of this review, discussion is confined to general patterns of shorebird abundance, distribution, and macro- and microhabitat use in natural coastal, estuarine, and barrier island habitats on the Gulf of Mexico Coast. The following geographic regions are considered: Northwestern Gulf (Rio Grande to Louisiana-Mississippi border), Northeastern Gulf (Mississippi to Florida Keys), and Mexico (Rio Grande to Cabo Catoche [Yucatan Strait]). Kim Withers Copyright © 2002 Kim Withers. All rights reserved. Coral Reefs: Beyond Mortality? Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2000/873583/abs/ The scale of the collapse of coral reef communities in 1998 following a warming episode (Wilkinson, 2000) was unprecedented, and took many people by surprise. The Indian Ocean was the worst affected with a coral mortality over 75% in many areas such as the Chagos Archipelago (Sheppard, 1999), Seychelles (Spencer et al., 2000) and Maldives (McClanahan, 2000). Several other locations were affected at least as much, with mortality reaching 100% (to the nearest whole number); this is being compiled by various authors (e.g., CORDIO, in press). For example, in the Arabian Gulf, coral mortality is almost total across many large areas of shallow water (Sheppard, unpublished; D. George and D. John, personal communication). The mortality is patchy of course, depending on currents, location inside or outside lagoons, etc., but it is now possible to swim for over 200 m and see not one remaining living coral or soft coral on some previously rich reefs. Charles Sheppard Copyright © 2000 Charles Sheppard. All rights reserved. Maryland Power Plant Cooling-Water Intake Regulations and their Application in Evaluation of Adverse Environmental Impact Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/874652/abs/ Maryland’s cooling-water intake and discharge regulations, the Code of Maryland Regulations (COMAR) 26.08.03, stem from Sections 316(a) and (b) of the Clean Water Act (CWA). COMAR 26.08.03.05 and litigative and administrative rulings stipulate that the location, design, construction, and capability of cooling-water intake structures must reflect the best technology available (BTA) for minimizing adverse environmental impacts (AEIs), providing that the costs of implementing the BTA are not wholly disproportionate to the expected environmental benefits. Maryland law exempts facilities that withdraw less than 10 million gallons/day (MGD) and less than 20% of stream or net flow by the intake. If not exempt, BTA must be installed if the cost of doing so is less than five times the value of fish impinged annually. Through site-specific studies and the use of a Spawning and Nursery Area of Consequence (SNAC) model applied to Representative Important Species, several power plants were evaluated to determine if they have had an adverse effect on spawning and nursery areas of consequence. Examples of application of the Maryland law to a number of power plants in the state are presented, together with the outcome of their evaluation. Richard McLean, William A. Richkus, Stephen P. Schreiner, and David Fluke Copyright © 2002 Richard McLean et al. All rights reserved. Carbon Reservoirs in Temperate South American Nothofagus Forests Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/876595/abs/ Humans are influencing the global carbon (C) cycle due to the combustion of fossil fuels and due to changes in land use management. These activities are fostering the manmade greenhouse effect and thus global climate change. Negative effects for life on earth are accounted for. Klaus Baswald, Jose D. Lencinas, and Gabriel Loguercio Copyright © 2002 Klaus Baswald et al. All rights reserved. The Effect of Stand Age on Throughfall Chemistry in Spruce Stands in the Potok Dupniański Catchment in the Silesian Beskid Mountains, Southern Poland Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/947912/abs/ The chemical composition of throughfall depends on the age of the Norway spruce (Picea abies Karst) stands and season of the year. The pH of throughfall decreased and the amount of hydrogen ion in throughfall deposited to the soil increased with increasing age of spruce stands, especially in the winter season. Concentrations of K+, H+, SO42−, Mn2+, and NH4+ in throughfall were higher than bulk precipitation for the whole year and K+, H+, and Mn2+ concentrations were higher in throughfall in winter and the growing season. This indicates that these ions were washed out or washed from the surface of needles and/or the bark, and that NO3−, NH4+, Ca2+, Mg2+, Fe2+, and Zn2+ were absorbed in the canopy. The effect of high nitrogen deposition, above critical loads, and an increase in the amount of sulfur and in the sum of the strong acids (S-SO42− and N-NO3−) that reached the soil with throughfall may have implications for the vitality of spruce stands, especially in older age classes. The application of Principal Component Analysis (PCA) has led to identification of five factors responsible for the data structure (“mineral dust”, “acidic emissions”, “heavy metals-dust particles”, “ammonium [NH4+]”, and “H+”). They explain more than 60% of the total variance system. The strong positive correlation between stand age class and ionic concentrations in throughfall occurs for all year and the winter period for ions within the following categories: “acidic emissions”, SO42− + NO3−; “heavy metals-dust particles”, Fe2+ + Mn2+ + Zn2+; “mineral dust”, Na+ + K+ + Ca+2 + Mg2+; “NH4+”; and “H+”. The strength of the relationship decreases in the growing period, probably due to processes occurring in the canopy (adsorption, leaching, etc.). Stanislaw Malek and Aleksander Astel Copyright © 2007 Stanisław Małek and Aleksander Astel. All rights reserved. Minimizing Adverse Environmental Impact: How Murky the Waters Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/950731/abs/ The withdrawal of water from the nation’s waterways to cool industrial facilities kills billions of adult, juvenile, and larval fish each year. U.S. Environmental Protection Agency (EPA) promulgation of categorical rules defining the best technology available to minimize adverse environmental impact (AEI) could standardize and improve the control of such mortality. However, in an attempt to avoid compliance costs, industry has seized on the statutory phrase “adverse environmental impact” to propose significant procedural and substantive hurdles and layers of uncertainty in the permitting of cooling-water intakes under the Clean Water Act. These include, among other things, a requirement to prove that a particular facility threatens the sustainability of an aquatic population as a prerequisite to regulation. Such claims have no foundation in science, law, or the English language. Any nontrivial aquatic mortality constitutes AEI, as the EPA and several state and federal regulatory agencies have properly acknowledged. The focus of scientists, lawyers, regulators, permit applicants, and other interested parties should not be on defining AEI, but rather on minimizing AEI, which requires minimization of impingement and entrainment. Reed W. Super and David K. Gordon Copyright © 2002 Reed W. Super and David K. Gordon. All rights reserved. Sediment Remediation for Ecosystem in Eutrophic Lakes Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/953696/abs/ The remediation method — namely, a hybrid system combined with DAF and CRM — is studied in this paper for the size reduction of aqua-ecological circulation and for the elution control in lakes. Results show that two effects on water quality purification, the sediment washout effect and the elution control effect, can be induced by this system, and the biota inhabiting the lake is therefore shifted into an oligotrophic aspect, from blue algae to green algae and/or diatoms. Y. Amano, K. Taki, K. Murakami, T. Ishii, and H. Matsushima Copyright © 2002 Y. Amano et al. All rights reserved. Diversity, Biodiversity, Conservation, and Sustainability Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/954202/abs/ The concepts of diversity and biodiversity are analysed regarding their historical emergence, and their intrinsic meaning and differences are discussed. Through a brief synopsis, difficulties usually experienced by statisticians in capturing the dynamics of diversity are analysed and main problems identified. The shift from diversity to the more holistic biodiversity as a working concept is appraised in terms of the novelty involved. Through a number of examples, the way the two concepts capture natural cyclic changes is analysed, and their reciprocal and complementary relations are approached theoretically. The way diversity could develop from the stores of biodiversity as its active expression through selective and evolutionary processes is described. Through the use of a very simple dynamic model, the concepts of diversity and biodiversity are analysed in extremely opposite hypothetical scenarios. Comparisons with natural situations are made and the theoretical implications from the conservation point of view are discussed. These support the opinion that conservation undertaken in restricted and protected areas is not self-sustainable, needing permanent external intervention to regulate internal processes, and in the long run will most probably lead in the direction of obsolescence and extinction. Finally, the relations between diversity, biodiversity, and sustainability are approached. The vagueness of the sustainability concept is discussed. Preservation of biodiversity is then defended as one of the best available indicators to assist us in fixing boundaries which may help to provide a more precise definition of sustainability. Joao Carlos Marques Copyright © 2001 Joao Carlos Marques. All rights reserved. Periphyton Function in Lake Ecosystems Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/923031/abs/ Periphyton communities have received relatively little attention in lake ecosystems. However, evidence is increasing that they play a key role in primary productivity, nutrient cycling, and food web interactions. This review summarizes those findings and places them in a conceptual framework to evaluate the functional importance of periphyton in lakes. The role of periphyton is conceptualized based on a spatial hierarchy. At the coarsest scale, landscape properties such as lake morphometry, influence the amount of available habitat for periphyton growth. Watershed-related properties, such as loading of dissolved organic matter, nutrients, and sediments influence light availability and hence periphyton productivity. At the finer scale of within the lake, both habitat availability and habitat type affect periphyton growth and abundance. In addition, periphyton and phytoplankton compete for available resources at the within-lake scale. Our review indicates that periphyton plays an important functional role in lake nutrient cycles and food webs, especially under such conditions as relatively shallow depths, nutrient-poor conditions, or high water-column transparency. We recommend more studies assessing periphyton function across a spectrum of lake morphometry and trophic conditions. Yvonne Vadeboncoeur and Alan D. Steinman Copyright © 2002 Yvonne Vadeboncoeur and Alan D. Steinman. All rights reserved. Policy Considerations for Using Forests to Mitigate Carbon Dioxide Emissions Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/930654/abs/ A recent article in Nature, “Soil Fertility Limits Carbon Sequestration by Forest Ecosystems in a CO2-Enriched Atmosphere” by Oren and colleagues[1], has been widely reported on, and often misinterpreted, by the press. The article dampens enthusiasm for accelerated forest growth due to CO2 fertilization and puts in question the fringe theory that the world’s forests can provide an automatic mitigation feedback. We agree that these results increase our understanding of the global carbon cycle. At the same time, their relevance in the context of the international climate change negotiations is much more complicated than portrayed by newspapers such as the New York Times (“Role of Trees in Curbing Greenhouse Gases is Challenged”, May 24, 2001) and the Christian Science Monitor (“Trees No Savior for Global Warming”, May 25, 2001). Sandra Brown, R. Neil Sampson, Bernhard Schlamadinger, and John Kinsman Copyright © 2001 Sandra Brown et al. All rights reserved. Acid Rain Phenomenon in Niger Delta Region of Nigeria: Economic, Biodiversity, and Public Health Concern Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2008/931839/ Rain samples were collected from Warri and Port Harcourt, two major oil-producing cities of Nigeria in April-June, July-August, and September-October 2005 and 2006. Awka, a “non-oil” city was used as control. Samples were collected from three points, using clean plastic basins fastened to a table, 2 m above ground level and 115 m away from tall buildings and trees. Water samples were filtered and acidity determined using digital pHmeter. The results show that the rain samples were acidic. The pH values for the 2 years under study show that the rainfall in Warri was more acidic than that of Port Harcourt. Oil exploration and other anthropogenic sources may be responsible for the acid rain in the Niger Delta region of Nigeria. J. K. C. Nduka, O. E. Orisakwe, L. O. Ezenweke, T. E. Ezenwa, M. N. Chendo, and N. G. Ezeabasili Copyright © 2008 J. K. C. Nduka et al. All rights reserved. Using Attainment of the Designated Aquatic Life Use to Determine Adverse Environmental Impact Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/935434/abs/ Section 316(b) of the Clean Water Act requires that cooling-water intake structures (CWIS) use Best Technology Available (BTA) to minimize adverse environmental impacts (AEI). The U.S. EPA has not defined AEI, and there is no clear consensus regarding its definition. Nonetheless, operational definitions are necessary to evaluate design alternatives and to measure the success of mitigative measures. Rather than having to develop measures of aquatic health that are highly site-specific, controversial, and often unlikely to elicit agreement from all sides of the environmental “fence”, it may be more productive to use existing ecological assessment tools. Aquatic Life Uses (ALU) already provide a regulatory framework to assess the quality (health) of the aquatic community in various habitats (e.g., warmwater habitat, exceptional warmwater habitat). Attainment of the ALU indicates that further point source controls are unnecessary, whereas nonattainment indicates that those pollutants or stressors causing the nonattainment must be reduced. A similar approach for existing water intakes is recommended. That is, attainment of the designated ALU will be taken as an indication that there is no AEI. Although attainment of the ALU may not be a foolproof indicator of a lack of AEI, this approach seems more reasonable that using scarce monetary resources to fix problems that likely do not exist, or having both regulators and the regulated community expend their resources debating whether various observed biological responses do or do not constitute AEI. Greg Seegert Copyright © 2002 Greg Seegert. All rights reserved. Modeling Possible Cooling-Water Intake System Impacts on Ohio River Fish Populations Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/936253/abs/ To assess the possible impacts caused by cooling-water intake system entrainment and impingement losses, populations of six target fish species near power plants on the Ohio River were modeled. A Leslie matrix model was constructed to allow an evaluation of bluegill, freshwater drum, emerald shiner, gizzard shad, sauger, and white bass populations within five river pools. Site-specific information on fish abundance and length-frequency distribution was obtained from long-term Ohio River Ecological Research Program and Ohio River Sanitation Commission (ORSANCO) electrofishing monitoring programs. Entrainment and impingement data were obtained from 316(b) demonstrations previously completed at eight Ohio River power plants. The model was first run under a scenario representative of current conditions, which included fish losses due to entrainment and impingement. The model was then rerun with these losses added back into the populations, representative of what would happen if all entrainment and impingement losses were eliminated. The model was run to represent a 50-year time period, which is a typical life span for an Ohio River coal-fired power plant. Percent changes between populations modeled with and without entrainment and impingement losses in each pool were compared to the mean interannual coefficient of variation (CV), a measure of normal fish population variability. In 6 of the 22 scenarios of fish species and river pools that were evaluated (6 species × 5 river pools, minus 8 species/river pool combinations that could not be evaluated due to insufficient fish data), the projected fish population change was greater than the expected variability of the existing fish population, indicating a possible adverse environmental impact. Given the number of other variables affecting fish populations and the conservative modeling approach, which assumed 100% mortality for all entrained fish and eggs, it was concluded that the likelihood of impact was by no means assured, even in these six cases. It was concluded that in most cases, current entrainment and impingement losses at six Ohio River power plants have little or no effect at the population level. Elgin Perry, Greg Seegert, Joe Vondruska, Timothy Lohner, and Randy Lewis Copyright © 2002 Elgin Perry et al. All rights reserved. Soil CO2 Efflux in a Mixed Pine-Oak Forest in Valsaín (Central Spain) Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/936280/abs/ Soil-surface CO2 efflux and its spatial and temporal variation were investigated in a southern Mediterranean, mixed pine-oak forest ecosystem on the northern slopes of the Sierra de Guadarrama in Spain from February 2006 to July 2006. Measurements of soil CO2 efflux, soil temperatures, and moisture were conducted in nine 1963-m2 sampling plots distributed in a gradient around the ecotone between Pinus sylvestris L. and Quercus pyrenaica Lam. forest stands. Total soil organic matter, Walkey-Black C, particulate organic matter, organic matter fraction below 53 μm, total soil nitrogen content, total soil organic carbon content, and pH were also measured under three representative mature oak, pine, and mixed pine-oak forest stands. Soil respiration showed a typical seasonal pattern with minimums in winter and summer, and maximums in spring, more pronounced in oak and oak-pine stands. Soil respiration values were highest in pine stands during winter and in oak stands during spring and summer. Rosa Inclán, Daniel De la Torre, Marta Benito, and Agustín Rubio Copyright © 2007 Rosa Inclán et al. All rights reserved. Air Pollution and Watershed Research in the Central Sierra Nevada of California: Nitrogen and Ozone Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/916017/abs/ Maintaining healthy forests is the major objective for the Forest Service scientists and managers working for the U.S. Department of Agriculture. Air pollution, specifically ozone (O3) and nitrogenous (N) air pollutants, may severely affect the health of forest ecosystems in the western U.S. Thus, the monitoring of air pollution concentration and deposition levels, as well as studies focused on understanding effects mechanisms, are essential for evaluation of risks associated with their presence. Such information is essential for development of proper management strategies for maintaining clean air, clean water, and healthy ecosystems on land managed by the Forest Service. We report on two years of research in the central Sierra Nevada of California, a semi-arid forest at elevations of 1100–2700 m. Information on O3 and N air pollutants is obtained from a network of 18 passive samplers. We relate the atmospheric N concentration to N concentrations in streams, shallow soil water, and bulk deposition collectors within the Kings River Experimental Watershed. This watershed also contains an intensive site that is part of a recent Forest Service effort to calculate critical loads for N, sulfur, and acidity to forest ecosystems. The passive sampler design allows for extensive spatial measurements while the watershed experiment provides intensive spatial data for future analysis of ecosystem processes. Carolyn Hunsaker, Andrzej Bytnerowicz, Jessica Auman, and Ricardo Cisneros Copyright © 2007 Carolyn Hunsaker et al. All rights reserved. Calculation of Theoretical and Empirical Nutrient N Critical Loads in the Mixed Conifer Ecosystems of Southern California Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/960654/abs/ Edaphic, foliar, and hydrologic forest nutrient status indicators from 15 mixed conifer forest stands in the Sierra Nevada, San Gabriel Mountains, and San Bernardino National Forest were used to estimate empirical or theoretical critical loads (CL) for nitrogen (N) as a nutrient. Soil acidification response to N deposition was also evaluated. Robust empirical relationships were found relating N deposition to plant N uptake (N in foliage), N fertility (litter C/N ratio), and soil acidification. However, no consistent empirical CL were obtained when the thresholds for parameters indicative of N excess from other types of ecosystems were used. Similarly, the highest theoretical CL for nutrient N calculated using the simple mass balance steady state model (estimates ranging from 1.4–8.8 kg N/ha/year) was approximately two times lower than the empirical observations. Further research is needed to derive the thresholds for indicators associated with the impairment of these mixed conifer forests exposed to chronic N deposition within a Mediterranean climate. Further development or parameterization of models for the calculation of theoretical critical loads suitable for these ecosystems will also be an important aspect of future critical loads research. Joan Breiner, Benjamin S. Gimeno, and Mark Fenn Copyright © 2007 Joan Breiner et al. All rights reserved. Monitoring of Ozone Risk for Forests in the Czech Republic: Preliminary Results Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2007/972545/abs/ Ozone (O3) is supposed to represent a significant risk for the health of forest ecosystems in Central Europe. So far, however, its impact on stands growing under natural conditions has not been clearly proved. A new project of the National Agency for the Research in Agriculture is focused on the O3 effect on selected parameters of forest health. This paper presents the results of the first year of monitoring, 2005. In 2005, high O3 concentrations were measured, mainly in the spring. In the summer, due to wet and cold weather, the O3 load was comparatively low. In the plots investigated, the concentrations of O3 were higher with the altitude. The amount of epicuticular waxes on 1-year-old Norway spruce needles was the only factor showing significant correlation to O3 concentration. Defoliation of the stands depended only on the stand age. The amount of malondialdehyde (MDA), an oxidative stress marker, was related to the altitude, and only for European beech. The results are preliminary, as the summer O3 development was not typical in 2005, and the results may change over the next monitoring periods. Vít Šrámek, Radek Novotný, Emilie Bednárová, and Hana Uhlírová Copyright © 2007 Vít Šrámek et al. All rights reserved. Influence of pH on Soil Charge Characteristics and Cadmium Sorption in Some Noncontaminated Soils of Indian Subtropics Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2005/986126/abs/ Concentrations of total dissolved cadmium (Cd) and activity of its free ions in soil solution are suggested to be influenced by soil pH, organic matter (OM) content, cation exchange capacity (CEC), and clay mineralogy. We investigated the sorption of Cd by taking 25-, 50-, and 100-µM Cd solutions in five noncontaminated soils of West Bengal, India, having differing chemical properties with batch sorption experiments. The charge characteristics and point of zero salt effect (PZSE) of all experimental soils were calculated by the potentiometric titration method measuring the adsorption of H+ and OH– on amphoteric surfaces in solutions of varying ionic strength (I). Sorption of Cd was more pronounced at pH levels greater than PZSE for all experimental soils. The CEC, OM content, clay mineralogy, and specific surface area (SSA) also had a great influence on the sorption of Cd from soil solution to soils. The relationships of Cd with those parameters were found to be consistent and the results concluded that Cd sorption in soils is strongly affected by the soil characteristics. Tanmoy Karak, Dilip Kumar Das, Uttam Kumar Singh, and Debtanu Maiti Copyright © 2005 Tanmoy Karak et al. All rights reserved. Adverse Environmental Impact: 30-Year Search for a Definition Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2002/986370/abs/ Since passage of the Clean Water Act in 1972, there has been a long, unresolved struggle to define a key phrase in Section 316(b) of the act: “adverse environmental impact” (AEI). Section 316(b) requires that the best technology available be used in cooling-water intake structures to minimize AEI due to entrainment and impingement of aquatic organisms. Various attempts were made to evaluate and define AEI, including focused national conferences on impact assessment. Unresolved arguments regarding AEI were reinvigorated following the 1995 Consent Decree requiring EPA to propose new rules to implement Section 316(b). This article reviews and compares eight proposed definitions of AEI. Six of the definitions define AEI as impact expressed at the population or higher level of biological organization. The two remaining definitions are unrelated to populations: a 1% cropping of the near-field organisms and “one fish equals AEI”. The latter definition is based on the desire of some stakeholders to define AEI as the loss of any public trust resources. Equating loss of public trust resources with AEI hampers consensus on a definition because a societal-based policy concept (public trust resources) is commingled with science-based definitions based on population effects. We recommend that a population-based definition of AEI be incorporated into Section 316(b) guidance and observe that this will not preclude a state from exercising its law and policy to protect public trust resources. David A. Mayhew, Paul H. Muessig, and Loren D. Jensen Copyright © 2002 David A. Mayhew et al. All rights reserved. Pesticides Are Involved With Population Declines of Amphibians in the California Sierra Nevadas Mon, 01 Jan 1900 00:00:00 +0000 http://www.hindawi.com/journals/tswj/2001/986410/abs/ Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog (Rana aurora), foothill yellow-legged frog (R. boylii), mountain yellow-legged frog (R. muscosa), Cascades frog (Rana cascadae), western toad (Bufo boreas) and Yosemite toad (B. canorus). For many of these species current distributions are down to 10% of historical ranges [1,2]. Several factors including introduced predators [3,4,5], habitat loss [2], and ultraviolet radiation [6] have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm). Prevailing westerly winds from the Pacific Coast transport these pesticides into the Sierras [7,8]. Donald W. Sparling, Gary Fellers, and Laura McConnell Copyright © 2001 Donald W. Sparling et al. All rights reserved.