Advances in Ecology http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Ecological Speciation and the Intertidal Snail Littorina saxatilis Tue, 22 Jul 2014 07:29:46 +0000 http://www.hindawi.com/journals/ae/2014/239251/ 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 http://www.hindawi.com/journals/ae/2014/456904/ 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 http://www.hindawi.com/journals/ae/2014/138360/ 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 http://www.hindawi.com/journals/ae/2014/286949/ 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 http://www.hindawi.com/journals/ae/2014/145056/ 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 http://www.hindawi.com/journals/ae/2014/430431/ 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 http://www.hindawi.com/journals/ae/2014/601813/ 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 http://www.hindawi.com/journals/ae/2014/532687/ 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.