International Journal of Ecology The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. 13C NMR and ESR Characterization of Humic Substances Isolated from Soils of Two Siberian Arctic Islands Thu, 12 Nov 2015 11:19:11 +0000 Humic acids (HAs) and fulvic acids (FAs) of two Polar soils were investigated by 13C NMR and ESR spectroscopies, investigating the degree of humification and the molecular structure. One soil, from Bolshoi Lyakhovsky Island, contains two humus horizons: modern and buried. The other soil, from Wrangel Island, had only one modern humus horizon. The HAs and FAs of the two soils investigated show essential differences. The HAs show fewer oxygen-containing groups in comparison with the FAs, whereas the degree of aromaticity is two or three times higher in the HAs. The 13C NMR data also show that HAs are very different from FAs in terms of their molecular composition and hydrophobicity. Humification in the Arctic is limited by the very low content of lignin-derived compounds, due to the restricted vascular flora. As a result, the HAs, isolated from Polar soils, are more similar to the corresponding FAs than to the typical HAs of temperate soils. This was confirmed by ESR data, which show similar levels of free radical concentration for HAs and FAs and are related to the low level of aromaticity of both materials investigated. Apparently, the humification process in the soils of Polar Arctic deserts is in an initial stage. E. Abakumov, E. Lodygin, and V. Tomashunas Copyright © 2015 E. Abakumov et al. All rights reserved. System Behaviour Charts Inform an Understanding of Biodiversity Recovery Tue, 10 Nov 2015 13:56:49 +0000 Practitioners working with species and ecosystem recovery typically deal with the complexity of, on one hand, lack of data or data uncertainties and, on the other hand, demand for critical decision-making and intervention. The control chart methods of commercial and industrial and environmental monitoring can complement an ecological understanding of wildlife systems including those situations which incorporate human activities and land use. Systems Behaviour Charts are based upon well-established control chart methods to provide conservation managers with an approach to using existing data and enable insight to aid timely planning of conservation interventions and also complement and stimulate research into wider scientific and ecological questions. When the approach is applied to existing data sets in well-known wildlife conservation cases, the subsequent Systems Behaviour Charts and associated analytical criteria demonstrate insights which would be helpful in averting problems associated with each case example. Simon A. Black Copyright © 2015 Simon A. Black. All rights reserved. Combining Niche Modelling, Land-Use Change, and Genetic Information to Assess the Conservation Status of Pouteria splendens Populations in Central Chile Tue, 10 Nov 2015 13:49:32 +0000 To assess the conservation status of a species with little ecological information is usually a challenging process. Pouteria splendens is an endemic shrub of the coastal range of Central Chile currently classified as lower risk (LR) by IUCN (version 2.3). Knowledge about this species is extremely limited. Currently P. splendens is only found in two small and isolated populations, which are thought to be remaining populations of an originally large metapopulation. However, there is no evidence to support this hypothesis, limiting our ability to gauge the real current conservation status of this species. In this study we combine niche modelling, land-use information, and genetic techniques to test the metapopulation hypothesis and reassess the conservation status of P. splendens using the IUCN criteria. We also evaluated the potential effects of climate change in the species distribution. Our results support the hypothesis of a large metapopulation that was recently fragmented. Future climate could increase the range of P. splendens; however the high level of fragmentation would preclude colonization processes. We recommend reclassifying P. splendens as Endangered (EN) and developing strategies to protect the remaining populations. Similar approaches like the presented here could be used to reclassify other species with limited ecological knowledge. Narkis S. Morales, Ignacio C. Fernández, Basilio Carrasco, and Cristina Orchard Copyright © 2015 Narkis S. Morales et al. All rights reserved. Recuperation of the Terra Firme Forest Understory Bird Fauna Eight Years after a Wildfire in Eastern Acre, Brazil Sun, 08 Nov 2015 07:09:18 +0000 The present study evaluated the characteristics of the understory bird fauna of four fragments of terra firme forest in eastern Acre, Brazil, that were impacted by wildfires in 2005. The study investigated the species richness and the composition of trophic guilds using mist-netting on eight transects (four in burned plots and four in control plots in the same forest fragments). Eight plots (0.12 ha) were also established parallel to each transect to record the number of live trees (DBH ≥ 10 cm), palms, and dead trees. Bamboo stems were quantified in 0.024 ha subplots. No significant difference was found between burned and control plots in the species richness or abundance of birds, nor was any significant pattern found in the NMDS ordination of the composition of the communities or guilds. The Principal Components Analysis (PCA) found that the burned plots were physiognomically distinct, due principally to the number of bamboo stems and dead trees. Multiple regressions based on the PCA scores and bird species richness and abundance found no significant trends. The findings of the present study indicate that the understory bird assemblage of the areas affected by a single wildfire in 2005 had almost totally recuperated eight years after this event. Tatiana Lemos da Silva, Edilaine Lemes Marques, and Edson Guilherme Copyright © 2015 Tatiana Lemos da Silva et al. All rights reserved. Effects of Tree Shelters on the Survival and Growth of Argania spinosa Seedlings in Mediterranean Arid Environment Wed, 04 Nov 2015 11:44:10 +0000 The argan tree is endemic species of Morocco. It occupies an area of more than 8700 km2 and plays essential ecological and economical roles. In spite of their value, the argan woodlands are subject to rapid and uncontrolled degradation during the last decades, mainly due to overgrazing and systematic collection of argan nuts. The present study was carried out to investigate the effects of two types of tree shelters on survival and growth of Argania spinosa seedlings planted in the southwest of Morocco in order to improve the results of reforestation programs which usually end by repeated failures. The experiment was conducted in the Mesguina forest for two growing seasons after transplantation in the field. After two years, the use of tree shelters significantly increased tree survival and allowed a gain of 20%. Height growth was positively affected by tree shelters. The use of tree shelters showed no significant decrease in basal diameter. In contrast, the height to diameter ratios of sheltered trees were much higher compared to the control. Thus, the use of the tree shelters could aid the early establishment and growth of Argania spinosa under conditions similar to those of the experiment. Chamchelmaarif Defaa, Salwa Elantry, Sanae Lahlimi El Alami, Ahmed Achour, Abdelhamid El Mousadik, and Fouad Msanda Copyright © 2015 Chamchelmaarif Defaa et al. All rights reserved. Nonconsumptive Effects of Predation and Impaired Chemosensory Risk Assessment on an Aquatic Prey Species Wed, 28 Oct 2015 09:48:47 +0000 Weak levels of acidity impair chemosensory risk assessment by aquatic species which may result in increased predator mortalities in the absence of compensatory avoidance mechanisms. Using replicate populations of wild juvenile Atlantic salmon (Salmo salar) in neutral and acidic streams, we conducted a series of observational studies and experiments to identify differences in behaviours that may compensate for the loss of chemosensory information on predation risk. Comparing the behavioural strategies of fish between neutral and acidic streams may elucidate the influence of environmental degradation on nonconsumptive effects (NCEs) of predation. Salmon in acidic streams are more active during the day than their counterparts in neutral streams, and are more likely to avoid occupying territories offering fewer physical refugia from predators. Captive cross-population transplant experiments indicate that at equal densities, salmon in acidic streams do not demonstrate relative decreases in growth rate as a result of their different behavioural strategies. Instead, altering diel activity patterns to maximize visual information use and occupying relatively safer territories appear sufficient to offset increased predation risk in acidic streams. Additional strategies such as elevated foraging rates during active periods or adopting riskier foraging tactics are necessary to account for the observed similarities in growth rates. Chris K. Elvidge and Grant E. Brown Copyright © 2015 Chris K. Elvidge and Grant E. Brown. All rights reserved. Tree Diversity and Community Composition of the Tutong White Sands, Brunei Darussalam: A Rare Tropical Heath Forest Ecosystem Tue, 27 Oct 2015 13:52:37 +0000 Bornean heath (Kerangas) forests are a unique and increasingly rare tropical forest ecosystem that remains little studied. We quantified tree floristic diversity in Kerangas forests in the Tutong White Sands, Brunei Darussalam, and investigated the influence of soil and environmental variables on community composition. Six 20 m × 20 m plots were established, where all trees of ≥5 cm diameter at breast height (DBH) were identified and measured to determine stem diameter and basal area. We determined pH, gravimetric water content, and concentrations of total nitrogen (N) and phosphorus (P) in topsoil, as well as litter depth and percentage canopy openness. A total of 296 trees were recorded, representing 78 species in 59 genera and 38 families. Stem diameter, basal area, species richness, and species diversity differed significantly among the six plots. The NMDS ordination revealed that differences in tree community compositions were significantly associated with total N concentrations and percentage canopy openness. Despite the small sampling area, we recorded several Bornean endemic tree species (16/78 tree species; 20.5%), including several IUCN Red List endangered and vulnerable species. Our results illustrate the potentially high conservation value of the Kerangas forests in the Tutong White Sands and highlight the urgent need to protect and conserve this area. Hazimah Din, Faizah Metali, and Rahayu Sukmaria Sukri Copyright © 2015 Hazimah Din et al. All rights reserved. Ecological Determinants of Forest to the Abundance of Lutzomyia longiflocosa in Tello, Colombia Mon, 28 Sep 2015 08:27:39 +0000 Lutzomyia longiflocosa is considered the most likely vector of cutaneous leishmaniasis in the sub-Andean region of the upper valley of the Magdalena River between 1,000 and 2,000 meters in the Department of Huila, Colombia. L. longiflocosa is anthropophilic, has endophagic behavior, and is especially important since its dominance in epidemics recorded in the last decade in the departments of Huila, Tolima, and the outbreak in Norte de Santander. The aim of our work is to identify ecological determinants in forest microhabitat level defining the abundance of L. longiflocosa. We use sampling; this was performed in 56 microhabitats of 28 forests with CDC traps for two consecutive nights from 18:00 to 06:00 hours. Each microhabitat (favorable and unfavorable) was located 10 m from the ecotone, with an approximate area of 10 m2. Thirty-five variables were examined as potential explanatory variables which were recorded in each microhabitat. Regression models were used to identify ecological determinants. Our results confirm that there are favorable microhabitats in the forest with specific ecological determinants that define the aggregated distribution of the species and provide the conditions necessary for survival and abundance of L. longiflocosa. Ruthber Rodríguez Serrezuela and Luis Alexander Carvajal Pinilla Copyright © 2015 Ruthber Rodríguez Serrezuela and Luis Alexander Carvajal Pinilla. All rights reserved. Cervus elaphus Foraging Impacts on Plants and Soils at an Ungrazed Desert Grass/Shrubland in Northwestern New Mexico, USA Tue, 08 Sep 2015 16:38:53 +0000 We evaluated Cervus elaphus herbivory and trampling impacts on plants and soils on Chaco Culture National Historical Park (Chaco), a desert grass/shrubland in northwestern New Mexico, USA, most (63%) of which has been protected from grazing by domestic livestock since 1948. We conducted grazing, browse, and water infiltration surveys in areas which received different amounts of C. elaphus use (use and control), 2004–2007. Browse utilization was <32% on monitored species and Odocoileus hemionus use accounted for the majority of browsing. Live plant cover was greater on areas receiving more C. elaphus use, and no grass species were used above recommended levels. Stubble heights of Bouteloua spp. were positively related to relative C. elaphus use on some areas, suggesting possible stimulation of grassland productivity by C. elaphus grazing. Water infiltration rates either did not differ among use or control sites or were faster in use sites, indicating no impacts of C. elaphus use on soil compaction. At current C. elaphus densities (0.2–0.4/km2), negative impacts to plants and soils were not seen on Chaco, and some evidence suggests that light grazing is optimizing desert grasslands of Chaco. Louis C. Bender and Jessica R. Piasecke Copyright © 2015 Louis C. Bender and Jessica R. Piasecke. All rights reserved. Home Range, Diet, and Activity Patterns of Common Marmosets (Callithrix jacchus) in Very Small and Isolated Fragments of the Atlantic Forest of Northeastern Brazil Tue, 18 Aug 2015 06:24:46 +0000 We evaluate the impact of very small and isolated forest fragments on the common marmosets home range, diet, and activity patterns, in the northeastern Atlantic Forest of Brazil. Three groups were studied in three forest fragments, from January to October 2010, totaling 360 hours of observations and 1,080 field-hours. Systematic observations were recorded using Instantaneous Scan Sampling, and a checklist of the items exploited was built through ad libitum observations. We recorded location of the groups and calculated home range. We recorded 11,639 scans and 236 ad libitum feeding records. 83.4% () of food items were plant species, the only animal protein was from insects (; 16.6%), and the diet was based almost exclusively on gums. Mean home range was 5.5 ha, mean daily path length was 1,167 meters, and no differences were detected between seasons. Resting dominated their activity budget and varied between seasons. Common marmosets survived in this environment through a remarkable increase in their exploitation of tree gums (up to 98% of their feeding bouts) to compensate for the lack of food, in home ranges slightly larger than in the literature. Thus, they travelled and foraged less than expected and rested more since food was easily obtained. Herbert Leonardo Nascimento Pinheiro and Antonio Rossano Mendes Pontes Copyright © 2015 Herbert Leonardo Nascimento Pinheiro and Antonio Rossano Mendes Pontes. All rights reserved. Changes in Allometric Attributes and Biomass of Forests and Woodlands across an Altitudinal and Rainfall Gradient: What Are the Implications of Increasing Seasonality due to Anthropogenic Climate Change? Tue, 28 Apr 2015 11:51:56 +0000 Canonical correspondence analysis and linear regressions were used to relate height, diameter, and dispersion measurements of 36,380 stems from 197 species recorded in 2,341 plots against both climatic and landscape variables. Above ground biomass increased in wetter and cooler locations that ameliorate the seasonal rainfall deficits. Taller and greater diameter trees with lower wood densities occur at higher altitudes. Differences between locations are based on a change in the composition of species rather than a change in the allometric properties within a species. The results support the hydraulic limitation and species packing hypotheses. These interrelationships may be affected by the interactions of fire frequency and drought which are a common feature of much of the study area. Under current climate change scenarios it is likely that there will be a reduction in above ground biomass, the number of stems per hectare, average height, average diameter, and basal area due to increasing seasonality of rainfall, temperatures, and the intensity and frequency of fires. The largest of trees are likely to be removed early due to their inability to cope with increased drought stress. The results suggest a marked reduction in carbon storage will occur across the study region in eastern Australia. John T. Hunter Copyright © 2015 John T. Hunter. All rights reserved. Seasonality of Climate Drives the Number of Tree Hollows in Eastern Australia: Implications of a Changing Climate Wed, 08 Apr 2015 13:38:22 +0000 Tree hollow number is investigated across an altitudinal and climatic gradient in eastern Australia. The relationship between seasonal climate and local site factors to hollow number at a regional scale was investigated. Moisture retention, rainfall, and solar radiation during the summer period were the highest contributing factors to hollow number in the model presented. The relationship of hollow number with the significant variables was unimodal in nature with either extreme causing a decline within the region. The results indicate that increased seasonality of rainfall, solar radiation, and temperatures as predicted by anthropogenic climate change will cause a shift in the optimal location for hollow number. Change in tree hollows is reliant on taxonomic replacement through dispersal and establishment and subsequently time to allow individuals to mature. The reduction in this resource stimulated by changes in seasonality predicted within the ensuing decades is likely to cause a loss of hollows across the landscape with the resource not being replaced for hundreds of years. The number of hollows within a landscape may drastically reduce due to climate change alone irrespective of tree clearing rates. John T. Hunter Copyright © 2015 John T. Hunter. All rights reserved. Modeling Aquatic Macroinvertebrate Richness Using Landscape Attributes Mon, 26 Jan 2015 06:53:47 +0000 We used a rapid, repeatable, and inexpensive geographic information system (GIS) approach to predict aquatic macroinvertebrate family richness using the landscape attributes stream gradient, riparian forest cover, and water quality. Stream segments in the Allegheny River basin were classified into eight habitat classes using these three landscape attributes. Biological databases linking macroinvertebrate families with habitat classes were developed using life habits, feeding guilds, and water quality preferences and tolerances for each family. The biological databases provided a link between fauna and habitat enabling estimation of family composition in each habitat class and hence richness predictions for each stream segment. No difference was detected between field collected and modeled predictions of macroinvertebrate families in a paired t-test. Further, predicted stream gradient, riparian forest cover, and total phosphorus, total nitrogen, and suspended sediment classifications matched observed classifications much more often than by chance alone. High gradient streams with forested riparian zones and good water quality were predicted to have the greatest macroinvertebrate family richness and changes in water quality were predicted to have the greatest impact on richness. Our findings indicate that our model can provide meaningful landscape scale macroinvertebrate family richness predictions from widely available data for use in focusing conservation planning efforts. Marcia S. Meixler and Mark B. Bain Copyright © 2015 Marcia S. Meixler and Mark B. Bain. All rights reserved. Potential Effects of the Loss of Native Grasses on Grassland Invertebrate Diversity in Southeastern Australia Mon, 01 Dec 2014 07:42:30 +0000 Reduction in area of the southeastern temperate grasslands of Australia since European settlement has been accompanied by degradation of remaining remnants by various factors, including the replacement of native plant species by introduced ones. There are suggestions that these replacements have had deleterious effects on the invertebrate grassland community, but there is little evidence to support these suggestions. In the eastern Adelaide Hills of South Australia, four grassland invertebrate sampling areas, in close proximity, were chosen to be as similar as possible except for the visible amount of native grass they contained. Sample areas were surveyed in four periods (summer, winter, spring, and a repeat summer) using pitfall traps and sweep-netting. A vegetation cover survey was conducted in spring. Morphospecies richness and Fisher’s alpha were compared and showed significant differences between sample areas, mainly in the summer periods. Regression analyses between morphospecies richness and various features of the groundcover/surface showed a strong positive and logical association between native grass cover and morphospecies richness. Two other associations with richness were less strong and lacked a logical explanation. If the suggested direct effect of native grass cover on invertebrate diversity is true, it has serious implications for the conservation of invertebrate biodiversity. Roger Edgcumbe Clay Copyright © 2014 Roger Edgcumbe Clay. All rights reserved. Edge Effects and the Population Structure of Humboldt Bay, California, Eelgrass (Zostera marina L.) Sun, 23 Nov 2014 08:19:26 +0000 The physical structure of a habitat (e.g., fragmentation) may affect the distribution of genetic diversity within a population, and genetic diversity may alter ecological function. This study investigates the population genetics of Humboldt Bay, California, eelgrass in light of the habitat’s fragmented physical structure. Historical and ongoing dredging operations in the bay maintain channels between fragmented tidal mudflats that are inhabited by eelgrass. A sample of 469 individuals, from 11 discrete fragments, was genotyped using microsatellite analysis. Ramets were collected at multiple points located at the edge and in the interior of each fragment. The sampling scheme was designed to detect evidence of population structure within and between fragments, as well as between edge and interior bed positions. Genetic diversity is not shown to differ among fragments and is not consistent with widespread clonality. Heterozygosity levels indicate that Hardy-Weinberg equilibrium predominates across loci in most instances. Comparisons of edge and interior bed positions also reveal similarities between positions for the metrics described above. Results suggest efficient gene flow between fragments and between bed positions. Such findings, which indicate the unstructured nature of the population, can guide resource managers in making evolutionarily informed conservation decisions by discouraging assumptions of low genetic diversity and insignificant sexual reproduction. Joshua S. Neely Copyright © 2014 Joshua S. Neely. All rights reserved. Litter Fall and Its Decomposition in Sapium sebiferum Roxb.: An Invasive Tree Species in Western Himalaya Thu, 13 Nov 2014 00:00:00 +0000 Recognizing that high litter fall and its rapid decomposition are key traits of invasive species, litter fall and its decay in Sapium sebiferum Roxb. were studied in Palampur. For this, litter traps of dimension 50 × 50 × 50 cm3 were placed in under-canopy and canopy gap of the species. Litter fall was monitored monthly and segregated into different components. For litter decay studies, litter bags of dimension 25 × 20 cm2 with a mesh size 2 mm were used and the same were analyzed on a fortnightly basis. Litter fall in both under-canopy and canopy gap was highest in November (1.16 Mg ha−1 y−1 in under-canopy and 0.38 Mg ha−1 y−1 in canopy gap) and lowest during March. Litter production in under-canopy and canopy gap was 4.04 Mg ha−1 y−1 and 1.87 Mg ha−1 y−1, respectively. These values are comparable to sal forest (1.7 t C ha−1 y−1), chir pine-mixed forest (2.1 t C ha−1 y−1), and mixed oak-conifer forest (2.8 t C ha−1 y−1) of the Western Himalaya. The decay rate, 0.46% day−1 in under-canopy and 0.48% day−1 in canopy gap, was also fast. Owing to this the species may be able to modify the habitats to its advantage, as has been reported elsewhere. Vikrant Jaryan, Sanjay Kr. Uniyal, R. C. Gupta, and R. D. Singh Copyright © 2014 Vikrant Jaryan et al. All rights reserved. Distribution and Conservation of Davilla (Dilleniaceae) in Brazilian Atlantic Forest Using Ecological Niche Modeling Wed, 12 Nov 2014 12:34:53 +0000 We have modeled the ecological niche for 12 plant species belonging to the genus Davilla (Dilleniaceae) which occur in the Atlantic Forest of Brazil. This group includes endemic species lianas threatened by extinction and is therefore a useful indicator for forest areas requiring conservation. The aims are to compare the distribution and richness of species within the protected areas, assessing the degree of protection and gap analysis of reserves for this group. We used the Maxent algorithm with environmental and occurrence data, and produced geographic distribution maps. The results show that high species richness occurs in forest and coastal forest of Espírito Santo to Bahia states. The endemic species comprise D. flexuosa, D. macrocarpa, D. flexuosa, D. grandifolia, and D. sessilifolia. In the Atlantic Forest of southeastern Brazil, the following endemic species occur: D. tintinnabulata and D. glaziovii, with this latter species being included in the “red list” due habitat loss and predatory extractivism. The indicators of species richness in the coastal region of Bahia correspond with floristic inventories that point to this area having a high biodiversity. Although this region has several protected areas, there are gaps in reserves, which, combined with anthropogenic threats and fragmentation, have caused several problems for biodiversity. Ismael Martins Pereira, Vera Lúcia Gomes-Klein, and Milton Groppo Copyright © 2014 Ismael Martins Pereira et al. All rights reserved. Assessment of the Bioavailability of Cu, Pb, and Zn through Petunia axillaris in Contaminated Soils Mon, 25 Aug 2014 09:45:18 +0000 Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and the potential accumulation. The aim of this examination is to evaluate the accumulation potential of Petunia x hybrida as a flower crop for three metals, namely, copper (Cu), lead (Pb), and nickel (Ni). Trace metals (Zn, Cu, and Pb) in the soils were partitioned by a sequential extraction procedure into H2O extractable (F1), 1 M CH3COONa extractable (F2). Chemical fractionation showed that F1 and F2 fraction of the metals were near 1% and residue was the dominant form for Zn, Cu, and Pb in all samples. Using fluorescence method allowed us to estimate condition of the plants by adding metals. As result of plant and soil analysis, we can conclude that Petunia has Cu, Zn, and Ni tolerance and accumulation. Therefore, Petunia has the potential to serve as a model species for developing herbaceous, ornamental plants for phytoremediation. Lydia Bondareva, Roman Teisserenc, Nina Pakharkova, Alexander Shubin, Théo Le Dantec, Leïla Renon, and Ivan Svoboda Copyright © 2014 Lydia Bondareva et al. All rights reserved. Responses of Soil Organic Carbon to Long-Term Understory Removal in Subtropical Cinnamomum camphora Stands Thu, 03 Jul 2014 06:43:38 +0000 We conducted a study on a 48-year-old Cinnamomum camphora plantation in the subtropics of China, by removing understory gradually and then comparing this treatment with a control (undisturbed). This study analyzed the content and storage soil organic carbon (SOC) in a soil depth of 0–60 cm. The results showed that SOC content was lower in understory removal (UR) treatment, with a decrease range from 5% to 34%, and a decline of 10.16 g·kg−1 and 8.58 g·kg−1 was noticed in 0–10 cm and 10–20 cm layers, respectively, with significant differences (). Carbon storage was reduced in UR, ranging from 2% to 43%, with a particular drastic decline of 15.39 t·hm−2 and 11.58 t·hm−2 in 0–10 cm () and 10–20 cm () layers, respectively. Content of SOC had an extremely significant () correlation with soil nutrients in the two stands, and the correlation coefficients of CK were higher than those of UR. Our data showed that the presence of understory favored the accumulation of soil organic carbon to a large extent. Therefore, long-term practice of understory removal weakens the function of forest ecosystem as a carbon sink. Yacong Wu, Zhengcai Li, Caifang Cheng, and Rongjie Liu Copyright © 2014 Yacong Wu et al. All rights reserved. Are Commonly Measured Functional Traits Involved in Tropical Tree Responses to Climate? Wed, 25 Jun 2014 11:11:01 +0000 Climate models predict significant rainfall reduction in Amazonia, reducing water availability for trees. We present how functional traits modulate the tree growth response to climate. We used data from 3 years of bimestrial growth measurements for 204 trees of 53 species in the forest of Paracou, French Guiana. We integrated climate variables from an eddy covariance tower and functional trait values describing life history, leaf, and stem economics. Our results indicated that the measured functional traits are to some extent linked to the response of trees to climate but they are poor predictors of the tree climate-induced growth variation. Tree growth was affected by water availability for most of the species with different species growth strategies in drought conditions. These strategies were linked to some functional traits, especially maximum height and wood density. These results suggest that (i) trees seem adapted to the dry season at Paracou but they show different growth responses to drought, (ii) drought response is linked to growth strategy and is partly explained by functional traits, and (iii) the limited part of the variation of tree growth explained by functional traits may be a strong limiting factor for the prediction of tree growth response to climate. Fabien Wagner, Vivien Rossi, Christopher Baraloto, Damien Bonal, Clément Stahl, and Bruno Hérault Copyright © 2014 Fabien Wagner et al. All rights reserved. Location and Roles of Deep Pools in Likangala River during 2012 Recession Period of Lake Chilwa Basin Tue, 03 Jun 2014 12:32:53 +0000 The ecological study focusing on Likangala River was conducted during the recent (2012) Lake Chilwa recession and aimed at identifying the important pools and the impact of indigenous ecological knowledge on the use and management of the aquatic biodiversity in the pools. An extensive georeferencing of the pools, field observations, and measurement of the pool depths was conducted to locate and map the deep pools along the river. Garmin Etrex Venture HC, GPS, and georeferencing were used to obtain the points and locate the place. Oral interviews with local leaders were conducted to understand the use and management of the pools by communities. The study showed that Likangala River has 17 pools with depths ranging from 1.85 m to 3.6 m. The pools act as habitats and feeding and spawning ground for various aquatic biodiversity. The study further found that some important deep pools have apparently become shallower during the past few years due to increased silt deposition from the upper part of the catchment. The study shows that deep pools are very important during Lake Chilwa recession and recommends the participatory fisheries management as the best way of sustaining the aquatic biodiversity and endangered species in Lake Chilwa basin. Rodgers Makwinja, Mphatso Chapotera, Patrick Likongwe, John Banda, and Asaf Chijere Copyright © 2014 Rodgers Makwinja et al. All rights reserved. Stabilizing Effect of Prey Refuge and Predator’s Interference on the Dynamics of Prey with Delayed Growth and Generalist Predator with Delayed Gestation Wed, 30 Apr 2014 07:24:42 +0000 In the present paper, I study a prey-predator model with multiple time delays where the predator population is regarded as generalist. For this regard, I consider a Holling-Tanner prey-predator system where a constant time delay is incorporated in the logistic growth of the prey to represent a delayed density dependent feedback mechanism and the second time delay is considered to account for the length of the gestation period of the predator. Predator’s interference in predator-prey relationship provides better descriptions of predator's feeding over a range of prey-predator abundances, so the predator's functional response here is considered to be Type II ratio-dependent. In accordance with previous studies, it is observed that delay destabilizes the system, in general, and stability loss occurs via Hopf bifurcation. There exist critical values of delay parameters below which the coexistence equilibrium is stable and above which it is unstable. Hopf bifurcation occurs when delay parameters cross their critical values. When delay parameters are large enough than their critical values, the system exhibits chaotic behavior and this abnormal behavior may be controlled by refuge. Numerical computation is also performed to validate different theoretical results. Lyapunov exponent, recurrence plot, and power spectral density confirm the chaotic dynamical behaviors. Debaldev Jana Copyright © 2014 Debaldev Jana. All rights reserved. A Comparison of Three Dry Matter Forage Production Methods Used in South Africa Sun, 27 Apr 2014 13:59:38 +0000 A common method for determining forage production of rangelands is by clipping and weighing forage from quadrats with predetermined areas. This technique is however time consuming. Other techniques which require less time and labour include amongst others using the disk pasture meter or phytomass derived from the vegetation classification program PHYTOTAB, in conjunction with the Plant Number Scale, which is used to determine vegetation canopy cover. The phytomass determined using PHYTOTAB/Plant Number Scale and the disk pasture meter was compared to the phytomass obtained from the actual clipping and weighing of forage. Tests showed that there were indeed statistically significant differences between the mean phytomass values of the three techniques. Considerable variation was shown in the results of the disk pasture meter readings compared to the other two techniques. The phytomass values obtained using the disk pasture meter were significantly higher than the phytomass determined using both the PHYTOTAB/Plant Number Scale and the clipping and weighing techniques. Results further indicated a significant similarity in the phytomass determined using the PHYTOTAB/Plant Number Scale and the clipping and weighing technique. The results of this pilot study need further investigation. A. J. Joubert and W. J. Myburgh Copyright © 2014 A. J. Joubert and W. J. Myburgh. All rights reserved. Semideciduous Seasonal Forest Production of Leaves and Deciduousness in Function of the Water Balance, LAI, and NDVI Mon, 31 Mar 2014 00:00:00 +0000 This study investigated the relationship between leaf production, litterfall, water balance, Leaf Area Index (LAI), and Normalized Difference Vegetation Index (NDVI) in semideciduous forests. The goal was to model this phenomenon to obtain the estimates of this component as an additional compartment of the ecosystem carbon sink. The tests were conducted in eight semideciduous forest fragments. Twenty-four permanent plots were monitored monthly and LAI measurements and weighing of litterfall deposited in nets were conducted for a period of thirteen months. In this period, Landsat 5 and IRS satellite images were obtained and processed for generation of NDVI. The water balance was calculated for each day. The relationship among the variables “leaf dry weight,” “LAI,” “NDVI,” and “water balance” was verified and a regression model was built and evaluated. The deciduous phenomenon can be explained by hydric balance, and LAI and NDVI are ancillary variables. The tendency of the variables in the period of 13 months was explained by quadratic functions. The varied behavior among the monitoring sites helped to know differences in the deposition of leaves. This study showed that only the leaf component of the litterfall of a semideciduous forest in tropical climate can capture 4 to 8 Mgha−1yr−1 of CO2 and this amount can be estimated using climate, biophysics, and vegetation index variables. Thomaz Correa e Castro da Costa, João Herbert Moreira Viana, and Juliana Leite Ribeiro Copyright © 2014 Thomaz Correa e Castro da Costa et al. All rights reserved. Potential Propagation by Seed and Cuttings of the Azorean Native Calluna vulgaris (L.) Hull Tue, 25 Mar 2014 08:00:40 +0000 This work investigates the potential propagation by seed and cuttings of the Azorean native Calluna vulgaris (L.) Hull. for landscape conservation. With that purpose we have performed several germination and cuttings trials, using plant material from wild populations of this species. In the germination trials, we tested the effects of photoperiod length (8 and 16 h), temperature (10, 15, 20, and 20–10°C), seed age (6, 108, and 270 days), temperature of seed storage (4°C and room temperature), and seed surface sterilization on the germination characteristics. In the cuttings trials, we tested the effects of stem cutting type, cultural conditions, cuttings’ harvest month, and rooting substrates on the rooting percentages. The best percentages of germination, 93 and 90%, were obtained with fresh seeds and surface sterilized and sown under an 8 h photoperiod and with temperatures of 10°C or 15°C, respectively; germination after seed storage during 270 days is significantly superior (71%) when seeds are stored at 4°C. The best percentages of rooting were achieved for straight (96%) or heel cuttings (90%) harvested in March, planted on soil from natural stands of C. vulgaris and Erica azorica Hochst., outdoors in half shade, and partially covered with transparent polyethylene film. Maria João Pereira, Helena Fagundo, Tiago Menezes, and João Couto Copyright © 2014 Maria João Pereira et al. All rights reserved. Venus Flytrap Seedlings Show Growth-Related Prey Size Specificity Tue, 18 Mar 2014 09:10:20 +0000 Venus flytrap (Dionaea muscipula) has had a conservation status of vulnerable since the 1970s. Little research has focussed on the ecology and even less has examined its juvenile stages. For the first time, reliance on invertebrate prey for growth was assessed in seedling Venus flytrap by systematic elimination of invertebrates from the growing environment. Prey were experimentally removed from a subset of Venus flytrap seedlings within a laboratory environment. The amount of growth was measured by measuring trap midrib length as a function of overall growth as well as prey spectrum. There was significantly lower growth in prey-eliminated plants than those utilising prey. This finding, although initially unsurprising, is actually contrary to the consensus that seedlings (traps < 5 mm) do not catch prey. Furthermore, flytrap was shown to have prey specificity at its different growth stages; the dominant prey size for seedlings did not trigger mature traps. Seedlings are capturing and utilising prey for nutrients to increase their overall trap size. These novel findings show Venus flytrap to have a much more complex evolutionary ecology than previously thought. Christopher R. Hatcher and Adam G. Hart Copyright © 2014 Christopher R. Hatcher and Adam G. Hart. All rights reserved. Understanding the Terrestrial Carbon Cycle: An Ecohydrological Perspective Tue, 04 Mar 2014 12:03:10 +0000 The terrestrial carbon (C) cycle has a great role in influencing the climate with complex interactions that are spatially and temporally variable and scale-related. Hence, it is essential that we fully understand the scale-specific complexities of the terrestrial C-cycle towards (1) strategic design of monitoring and experimental initiatives and (2) also developing conceptualizations for modeling purposes. These complexities arise due to the nonlinear interactions of various components that govern the fluxes of mass and energy across the soil-plant-atmospheric continuum. Considering the critical role played by hydrological processes in governing the biogeochemical and plant physiological processes, a coupled representation of these three components (collectively referred to as ecohydrological approach) is critical to explain the complexity in the terrestrial C-cycling processes. In this regard, we synthesize the research works conducted in this broad area and bring them to a common platform with an ecohydrological spirit. This could aid in the development of novel concepts of nonlinear ecohydrological interactions and thereby help reduce the current uncertainties in the terrestrial C-cycling process. The usefulness of spatially explicit and process-based ecohydrological models that have tight coupling between hydrological, ecophysiological, and biogeochemical processes is also discussed. Ajit Govind and Jyothi Kumari Copyright © 2014 Ajit Govind and Jyothi Kumari. All rights reserved. Adaptation of Australia’s Marine Ecosystems to Climate Change: Using Science to Inform Conservation Management Tue, 25 Feb 2014 08:28:25 +0000 The challenges that climate change poses for marine ecosystems are already manifesting in impacts at the species, population, and community levels in Australia, particularly in Tasmania and tropical northern Australia. Many species and habitats are already under threat as a result of human activities, and the additional pressure from climate change significantly increases the challenge for marine conservation and management. Climate change impacts are expected to magnify as sea surface temperatures, ocean chemistry, ocean circulation, sea level, rainfall, and storm patterns continue to change this century. In particular, keystone species that form the foundation of marine habitats, such as coral reefs, kelp beds, and temperate rocky reefs, are projected to pass thresholds with subsequent implications for communities and ecosystems. This review synthesises recent science in this field: the observed impacts and responses of marine ecosystems to climate change, ecological thresholds of change, and strategies for marine conservation to promote adaptation. Increasing observations of climate-related impacts on Australia’s marine ecosystems—both temperate and tropical—are making adaptive management more important than ever before. Our increased understanding of the impacts and responses of marine ecosystems to climate change provides a focus for “no-regrets” adaptations that can be implemented now and refined as knowledge improves. Johanna E. Johnson and Neil J. Holbrook Copyright © 2014 Johanna E. Johnson and Neil J. Holbrook. All rights reserved. Impact of Environmental Changes on Migratory Bird Survival Wed, 19 Feb 2014 00:00:00 +0000 We present a mathematical model that studies and simulates the interconnection between energetic and ecological aspects of bird migration. By comparing model predictions with experimental data, we show that it can be used to assess the impact of changing environmental conditions in breeding, wintering, and stop-over sites on migratory success. We relate in particular to the European white stork (Ciconia ciconia) and its Eastern migration route and discuss questions concerning the timing, stopover, and feeding behavior en route. Opinions concerning the importance of resource availability and resource quality en route are divided. Whereas some studies have shown that storks gain weight in the wintering site, but almost do not feed en route, others stress the importance of the quality of stop-over locations. We address these questions and simulate the development of stork populations for changing environmental conditions. We demonstrate that resource availability and competition for breeding sites are crucial factors determining the timing of spring migration and the length of stop-over periods. Analyzing the robustness of migration strategies with respect to changing environmental conditions, we show that birds will shorten their stay in stop-over places of poor resource availability rather than prolonging it in the attempt to gain time for accumulating fat reserves. Sabine Stöcker-Segre and Daniel Weihs Copyright © 2014 Sabine Stöcker-Segre and Daniel Weihs. All rights reserved. Biological Monitoring Using Macroinvertebrates as Bioindicators of Water Quality of Maroaga Stream in the Maroaga Cave System, Presidente Figueiredo, Amazon, Brazil Mon, 17 Feb 2014 12:52:12 +0000 Aquatic environments are being modified by anthropogenic activities regarding their biological, physical, and chemical conditions; even pristine aquatic ecosystems can be threatened. This study focused on the biological monitoring of Maroaga Stream—a first order stream located in an Environmental Protection Area in the Amazon using the Biological Monitoring Working Party (BMWP) Score System. The BMWP Score System revealed that the Maroaga Stream was a Class I stream (score of 138 points), indicating clean or not significantly altered water quality. The results suggest the adequate environmental conditions and ecological responses of the Maroaga Stream. Christiane Brito Uherek and Fernando Bernardo Pinto Gouveia Copyright © 2014 Christiane Brito Uherek and Fernando Bernardo Pinto Gouveia. All rights reserved.