نتایج جستجو برای: species richness
تعداد نتایج: 556166 فیلتر نتایج به سال:
Determination of factors affecting on species distribution and diversity, especially in desert areas is the most important factor in rangeland ecosystems management for encountering biological stress. In order to evaluate the effect of physiographic factors on plant biodiversity in natural ecosystems of Kakhk Gonabad, this research was conducted in spring 2014. First, by overlaying four maps of...
considering the importance of biodiversity conservation and protection assessment activities, the present filed study was conducted with aim to compare vegetation diversity of two areas with different levels of protection including ghorkhod protected area with seasonal grazing and golestan national park without grazing, during spring and summer of 2011. four replications were selected in each a...
There is considerable interest in determining whether the species richness of communities is determined by forces controlling dispersal into patches that operate at the landscape scale, or forces controlling persistence that act at the local scale. Understanding the relative importance of these two classes of factors in controlling within-patch species richness is particularly important when pa...
Aim In this study, we examine patterns of local and regional ant species richness along three elevational gradients in an arid ecosystem. In addition, we test the hypothesis that changes in ant species richness with elevation are related to elevation-dependent changes in climate and available area. Location Spring Mountains, Nevada, U.S.A. Methods We used pitfall traps placed at each 100-m elev...
Wu, J. and Vankat, J.L., 1991. An area-based model of species richness dynamics of forest islands. Ecol. Modelling, 58: 249-271. Landscape fragmentation results in forest islands surrounded by a matrix of agricultural and urban lands. Species richness of forest islands may be composed of edge species and interior species, at least above the minimum size necessary for the interior species. The s...
The consistent decrease in species richness with latitude shows several exceptions among marine organisms. We hypothesize that contrasting latitudinal diversity gradients can be explained by differences in critical life-history attributes, such as mode of larval development (MLD). We deconstructed latitudinal species richness patterns of marine benthic invertebrates according to MLD to elucidat...
What determines large-scale patterns of species richness remains one of the most controversial issues in ecology. Using the distribution maps of 11 405 woody species in China, we compared the effects of habitat heterogeneity, human activities and different aspects of climate, particularly environmental energy, water-energy dynamics and winter frost, and explored how biogeographic affinities (tr...
the diversity and richness of species are of important components to evaluate the health of ecologic system of rangelands. this research was conducted to investigate the biodiversity in riparian and neighboring areas via comparison of indices in javaherdeh rangeland of ramsar. plot-transects was randomly used to estimate diversity, richness, dominance, and evenness indices in two regions. multi...
Coral reefs are facing a biodiversity crisis due to increasing human impacts, consequently, one third of reef-building corals have an elevated risk of extinction. Logistic challenges prevent broad-scale species-level monitoring of hard corals; hence it has become critical that effective proxy indicators of species richness are established. This study tests how accurately three potential proxy i...
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