Advances in Ecology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Structuring Effects of Deer in Boreal Forest Ecosystems Tue, 16 Sep 2014 08:34:06 +0000 Many deer populations have recently increased worldwide leading to strong direct and indirect ecological and socioeconomical impacts on the composition, dynamic, and functions of forest ecosystems. Deer directly modify the composition and structure of vegetation communities, but they also indirectly affect other species of the ecosystem by modifying the structure of the vegetation. Here we review the results of a research program on overabundant white-tailed deer (Odocoileus virginianus) in the boreal forest of Anticosti Island (Québec, Canada) aimed at identifying deer densities compatible with forest regeneration. Various silvicultural systems and treatments failed to regenerate deer habitat at high deer densities, but planting size-adapted seedlings could be effective at moderate densities. Using a controlled deer density experiment, we found vegetation recovery at deer densities ≤ 15 deer/km2. The same experiment revealed that other groups of organisms such as insects and birds responded favorably to a reduction of deer density. We also found that alternative successional trajectories may occur after a certain period of heavy browsing during early succession. We conclude that one of the most important remaining research gaps is the need to identify habitat-specific threshold densities at which deer impacts occur and then to design effective wildlife and forest management strategies to limit deer impacts and sustain ecosystem integrity. Steeve D. Côté, Julien Beguin, Sonia de Bellefeuille, Emilie Champagne, Nelson Thiffault, and Jean-Pierre Tremblay Copyright © 2014 Steeve D. Côté et al. All rights reserved. Phosphate-Mediated Remediation of Metals and Radionuclides Thu, 11 Sep 2014 13:18:45 +0000 Worldwide industrialization activities create vast amounts of organic and inorganic waste streams that frequently result in significant soil and groundwater contamination. Metals and radionuclides are of particular concern due to their mobility and long-term persistence in aquatic and terrestrial environments. As the global population increases, the demand for safe, contaminant-free soil and groundwater will increase as will the need for effective and inexpensive remediation strategies. Remediation strategies that include physical and chemical methods (i.e., abiotic) or biological activities have been shown to impede the migration of radionuclide and metal contaminants within soil and groundwater. However, abiotic remediation methods are often too costly owing to the quantities and volumes of soils and/or groundwater requiring treatment. The in situ sequestration of metals and radionuclides mediated by biological activities associated with microbial phosphorus metabolism is a promising and less costly addition to our existing remediation methods. This review highlights the current strategies for abiotic and microbial phosphate-mediated techniques for uranium and metal remediation. Robert J. Martinez, Melanie J. Beazley, and Patricia A. Sobecky Copyright © 2014 Robert J. Martinez et al. All rights reserved. Status of Biodiversity at Wetland Ecosystem of Mohangonj Upazila in Netrakona District Tue, 02 Sep 2014 06:28:06 +0000 Species in wetlands provide ecosystem services, and protect the sustainable environment for human beings. The wetland biodiversity has been impacted at Mohangonj in Bangladesh due to the development of major environmental threats. The present research is undertaken to report the species status, wetland properties, and major environmental pressures in each wetland ecosystem. Among the recorded species, the total percentage of visible, threatened, endangered, and extinct species was 69.23, 18.62, 10, and 1.92% in these wetland ecosystems, respectively. The highest number of threatened species was found in the wetland of Aizda (29%); the lowest was in Khalaura (8%). The maximum number of endangered species was noted in the wetland of Sonarthal (16%), and the minimum was in Chadra (4%) wetland. Four percent species were in the extinct category at some of the wetland ecosystems. Wetland biodiversity protects wetland ecosystem services and the sustainable environment for species conservation. Continuous monitoring of wetland biodiversity might be helpful for the conservation of species in the wetland ecosystem. Mohammad Zahangeer Alam Copyright © 2014 Mohammad Zahangeer Alam. All rights reserved. Microevolutionary Effects of Habitat Fragmentation on Plant-Animal Interactions Mon, 25 Aug 2014 10:54:50 +0000 Plant-animal interactions are a key component for biodiversity maintenance, but they are currently threatened by human activities. Habitat fragmentation might alter ecological interactions due to demographic changes, spatial discontinuities, and edge effects. Also, there are less evident effects of habitat fragmentation that potentially alter selective forces and compromise the fitness of the interacting species. Changes in the mutualistic and antagonistic interactions in fragmented habitats could significantly influence the plant reproductive output and the fauna assemblage associated with. Fragmented habitats may trigger contemporary evolution processes and open new evolutionary opportunities. Interacting parties with a diffuse and asymmetric relationship are less susceptible to local extinction but more prone to evolve towards new interactions or autonomy. However, highly specialized mutualisms are likely to disappear. On the other hand, ecological interactions may mutually modulate their response in fragmented habitats, especially when antagonistic interactions disrupt mutualistic ones. Ecoevolutionary issues of habitat fragmentation have been little explored, but the empiric evidence available suggests that the complex modification of ecological interactions in fragmented habitats might lead to nonanalogous communities on the long term. Francisco E. Fontúrbel and Maureen M. Murúa Copyright © 2014 Francisco E. Fontúrbel and Maureen M. Murúa. All rights reserved. Saltcedar (Tamarix ramosissima) Invasion Alters Decomposer Fauna and Plant Litter Decomposition in a Temperate Xerophytic Deciduous Forest Thu, 21 Aug 2014 05:32:43 +0000 Plant invasions may alter the soil system by changing litter quality and quantity, thereby affecting soil community and ecosystem processes. We investigated the effect of Tamarix ramosissima invasion on the decomposer fauna and litter decomposition process, as well as the importance of litter quality in decomposition. Litter decomposition and decomposer communities were evaluated in two monospecific saltcedar forests and two native forests in Argentina, in litterbags containing either local litter (saltcedar or dominant native species) or a control litter. Saltcedar invasion produced an increase in Collembola, Acari, and total mesofauna abundance, regardless of the litter type. Control litter decomposition was higher in the native forest than in the saltcedar forest, showing that increased abundance of decomposer fauna does not necessarily accelerate decomposition processes. Local litter decomposition was not different between forests, suggesting that decomposer fauna of both ecosystems is adapted to efficiently decompose the autochthonous litter. Our results suggest that the introduction of a resource with higher quality than the local one has a negative effect on decomposition in both ecosystems, which is more pronounced in the invaded forest than in the native forest. This finding stresses the low plasticity of saltcedar decomposer community to adapt to short-term environmental changes. José Camilo Bedano, Laura Sacchi, Evangelina Natale, and Herminda Reinoso Copyright © 2014 José Camilo Bedano et al. All rights reserved. Community Structure and Distribution Pattern of Intertidal Invertebrate Macrofauna at Some Anthropogenically Influenced Coasts of Kathiawar Peninsula (India) Wed, 06 Aug 2014 00:00:00 +0000 Present communication reports the community structure and distribution pattern of intertidal invertebrate macrofauna at four shores of the Kathiawar peninsular coastline off the Arabian Sea (India). The selected shores have different levels of human activities. Present report tests three hypotheses; that is, (i) distribution of invertebrate macrofauna in these shores is influenced by space and time, (ii) abiotic factors have a profound influence on the distribution pattern of intertidal macrofaunal assemblages, and (iii) human activities influence the community structure of the intertidal invertebrate macrofauna at these shores. To test these hypotheses, spatiotemporal variations in different ecological indices were studied. A total of 60 species from six phyla were considered for the study. High species diversity was recorded during winter and monsoon seasons in almost all the shores studied. It was also evident that a few environmental factors had a cumulative influence on the distribution pattern of intertidal macrofauna. Significant spatial variations in the species diversity and evenness were also observed. Though the shores studied have similar coast characteristics and climatic conditions, they face different levels of human activities. Therefore, the observed variations in the intertidal faunal assemblage were possibly caused by anthropogenic stress. Poonam Bhadja, Paresh Poriya, and Rahul Kundu Copyright © 2014 Poonam Bhadja et al. All rights reserved. Ecological Speciation and the Intertidal Snail Littorina saxatilis Tue, 22 Jul 2014 07:29:46 +0000 In recent decades biologists studying speciation have come to consider that the process does not necessarily require the presence of a geographical barrier. Rather, it now seems to be possible for reproductive barriers to evolve within what was hitherto a single ‘‘species.’’ The intertidal snail Littorina saxatilis has been the focus of a considerable amount of work in this context, and it is now thought of as a good case study of ‘‘ecological speciation.’’ We review some of this work and briefly consider prospects for future developments. Juan Galindo and John W. Grahame Copyright © 2014 Juan Galindo and John W. Grahame. All rights reserved. Experiments Are Revealing a Foundation Species: A Case Study of Eastern Hemlock (Tsuga canadensis) Thu, 17 Jul 2014 07:51:02 +0000 Foundation species are species that create and define particular ecosystems; control in large measure the distribution and abundance of associated flora and fauna; and modulate core ecosystem processes, such as energy flux and biogeochemical cycles. However, whether a particular species plays a foundational role in a system is not simply asserted. Rather, it is a hypothesis to be tested, and such tests are best done with large-scale, long-term manipulative experiments. The utility of such experiments is illustrated through a review of the Harvard Forest Hemlock Removal Experiment (HF-HeRE), a multidecadal, multihectare experiment designed to test the foundational role of eastern hemlock, Tsuga canadensis, in eastern North American forests. Experimental removal of T. canadensis has revealed that after 10 years, this species has pronounced, long-term effects on associated flora and fauna, but shorter-term effects on energy flux and nutrient cycles. We hypothesize that on century-long scales, slower changes in soil microbial associates will further alter ecosystem processes in T. canadensis stands. HF-HeRE may indeed continue for >100 years, but at such time scales, episodic disturbances and changes in regional climate and land cover can be expected to interact in novel ways with these forests and their foundation species. Aaron M. Ellison Copyright © 2014 Aaron M. Ellison. All rights reserved. Distribution and Diversity of Oligochaetes in Selected Ponds of Thiruvananthapuram District, Kerala, South India Thu, 17 Jul 2014 07:44:18 +0000 The present study was carried out to evaluate the distribution and diversity of oligochaete fauna in selected ponds of Thiruvananthapuram district in Kerala, South India. The sediment samples were collected from three ponds seasonally during the period December 2006 to November 2008. In the study, 10 oligochaete species which belong to 8 genera were identified in three selected ponds. These include Dero digitata, Dero nivea, Dero obtusa, Pristina longiseta, Aulophorus furcatus, Stylaria fossularis, Chaetogaster spp., Aeolosoma spp., Tubifex tubifex and Limnodrilus hoffmeisteri. Tubifex tubifex and Limnodrilus hoffmeisteri are the pollution-indicator oligochaete species identified in the fresh water ponds, which reveals that the studied ponds are subjected to pollution. M. S. Ragi and D. S. Jaya Copyright © 2014 M. S. Ragi and D. S. Jaya. All rights reserved. Leopard Panthera pardus fusca Density in the Seasonally Dry, Subtropical Forest in the Bhabhar of Terai Arc, Nepal Wed, 16 Jul 2014 15:57:57 +0000 We estimated leopard (Panthera pardus fusca) abundance and density in the Bhabhar physiographic region in Parsa Wildlife Reserve, Nepal. The camera trap grid, covering sampling area of 289 km2 with 88 locations, accumulated 1,342 trap nights in 64 days in the winter season of 2008-2009 and photographed 19 individual leopards. Using models incorporating heterogeneity, we estimated 28 (±SE 6.07) and 29.58 (±SE 10.44) leopards in Programs CAPTURE and MARK. Density estimates via 1/2 MMDM methods were 5.61 (±SE 1.30) and 5.93 (±SE 2.15) leopards per 100 km2 using abundance estimates from CAPTURE and MARK, respectively. Spatially explicit capture recapture (SECR) models resulted in lower density estimates, 3.78 (±SE 0.85) and 3.48 (±SE 0.83) leopards per 100 km2, in likelihood based program DENSITY and Bayesian based program SPACECAP, respectively. The 1/2 MMDM methods have been known to provide much higher density estimates than SECR modelling techniques. However, our SECR models resulted in high leopard density comparable to areas considered better habitat in Nepal indicating a potentially dense population compared to other sites. We provide the first density estimates for leopards in the Bhabhar and a baseline for long term population monitoring of leopards in Parsa Wildlife Reserve and across the Terai Arc. Kanchan Thapa, Rinjan Shrestha, Jhamak Karki, Gokarna Jung Thapa, Naresh Subedi, Narendra Man Babu Pradhan, Maheshwar Dhakal, Pradeep Khanal, and Marcella J. Kelly Copyright © 2014 Kanchan Thapa et al. All rights reserved. Occurrence of Malabar Snakehead, Channa diplogramma (Perciformes: Channidae) from River Valapattanam, Western Ghats of Kerala, India Tue, 08 Jul 2014 11:53:58 +0000 We report the occurrence of Channa diplogramma in the Valapattanam River in March 2013 and this study adds to the species record of C. diplogramma in terms of diversity and range distribution in the River Valapattanam and South India. Sajan Sajeevan, Anna Mercy T. Varkey, and Mithun Sukumaran Copyright © 2014 Sajan Sajeevan et al. All rights reserved. Harvesting as an Alternative to Burning for Managing Spinifex Grasslands in Australia Sun, 06 Jul 2014 06:29:16 +0000 Sustainable harvesting of grasslands can buffer large scale wildfires and the harvested biomass can be used for various products. Spinifex (Triodia spp.) grasslands cover ≈30% of the Australian continent and form the dominant vegetation in the driest regions. Harvesting near settlements is being considered as a means to reduce the occurrence and intensity of wildfires and to source biomaterials for sustainable desert living. However, it is unknown if harvesting spinifex grasslands can be done sustainably without loss of biodiversity and ecosystem function. We examined the trajectory of plant regeneration of burned and harvested spinifex grassland, floristic diversity, nutrient concentrations in soil and plants, and seed germination in controlled ex situ conditions. After two to three years of burning or harvesting in dry or wet seasons, species richness, diversity, and concentrations of most nutrients in soil and leaves of regenerating spinifex plants were overall similar in burned and harvested plots. Germination tests showed that 20% of species require fire-related cues to trigger germination, indicating that fire is essential for the regeneration of some species. Further experimentation should evaluate these findings and explore if harvesting and intervention, such as sowing of fire-cued seeds, allow sustainable, localised harvesting of spinifex grasslands. Harshi K. Gamage, Paul Memmott, Jennifer Firn, and Susanne Schmidt Copyright © 2014 Harshi K. Gamage et al. All rights reserved. Effects of Climate Change and Various Grassland Management Practices on Grasshopper (Orthoptera) Assemblages Wed, 02 Jul 2014 09:11:28 +0000 Influence of different grassland management practices on Orthoptera assemblages inhabiting humid grassland areas was studied since 2003 to 2011. The examined sites were within the protected area of Balaton Uplands National Park. The physiognomy and climatic conditions of the studied habitats were similar but their land use types were significantly different. After the preliminary analyses of Nonmetric multidimensional scaling, neighbour joining clustering, and Spearman rank correlation, we examined the possible effects of such independent variables as land use (nonmanagement, mowing, grazing), microclimate (humidity and temperature), regional macroclimate (annual and monthly mean temperatures and rainfall), using General Linear Mixed Models, and canonical correlation analysis. Our results showed that the effect of grassland management practices on the organization of Orthoptera assemblages was at least as important as that of macro- and microclimate. Furthermore, grassland management could intensify the influence of several local and regional parameters. These results can help finding the most suitable type of grassland management to conserve the grasshopper assemblages. Zoltán Kenyeres and Judit Cservenka Copyright © 2014 Zoltán Kenyeres and Judit Cservenka. All rights reserved. Living at the Limits: Evidence for Microbial Eukaryotes Thriving under Pressure in Deep Anoxic, Hypersaline Habitats Thu, 08 May 2014 13:08:06 +0000 The advent of molecular tools in microbial ecology paved the way to exploit the diversity of microbes in extreme environments. Here, we review these tools as applied in one of the most polyextreme habitats known on our planet, namely, deep hypersaline anoxic basins (DHABs), located at ca. 3000–3500 m depth in the Eastern Mediterranean Sea. Molecular gene signatures amplified from environmental DHAB samples identified a high degree of genetic novelty, as well as distinct communities in the DHABs. Canonical correspondence analyses provided strong evidence that salinity, ion composition, and anoxia were the strongest selection factors shaping protistan community structures, largely preventing cross-colonization among the individual basins. Thus, each investigated basin represents a unique habitat (“isolated islands of evolution”), making DHABs ideal model sites to test evolutionary hypotheses. Fluorescence in situ hybridization assays using specifically designed probes revealed that the obtained genetic signatures indeed originated from indigenous polyextremophiles. Electron microscopy imaging revealed unknown ciliates densely covered with prokaryote ectosymbionts, which may enable adaptations of eukaryotes to DHAB conditions. The research reviewed here significantly advanced our knowledge on polyextremophile eukaryotes, which are excellent models for a number of biological research areas, including ecology, diversity, biotechnology, evolutionary research, physiology, and astrobiology. Thorsten Stoeck, Sabine Filker, Virginia Edgcomb, William Orsi, Michail M. Yakimov, Maria Pachiadaki, Hans-Werner Breiner, Violetta LaCono, and Alexandra Stock Copyright © 2014 Thorsten Stoeck et al. All rights reserved.