نتایج جستجو برای: diversity indices
تعداد نتایج: 268614 فیلتر نتایج به سال:
Large-scale studies focused on the diversity of continental slope ecosystems are still rare, usually restricted to a limited number of diversity indices and mainly based on the empirical comparison of heterogeneous local data sets. In contrast, we investigate large-scale fish diversity on the basis of multiple diversity indices and using 1454 standardized trawl hauls collected throughout the up...
This study was carried out in managed and unmanaged Fagus orientalis L. (beech) stands in the Asalem beech forest in order to compare the composition and diversity of plant species. Three V-shaped catena landforms were selected for each stand. Then, large quadrats, 400 m2 area, with selective method and within each of them, small quadrats, 4 m2 area, were established along each catena and slope...
A biological assessment of the Tang Sorkh River (Iran) was studied from July 2013 to August 2014 using benthic macroinvertebrate communities. Samples were gathered every two months, from five stations using a Surber sampler( 30×30cm), fixed in formalin (4%) and then separated and identified in the laboratory. Environmental conditions (current velocity, temperature, depth, width, dissolve oxygen...
A biological assessment of the Tang Sorkh River (Iran) was studied from July 2013 to August 2014 using benthic macroinvertebrate communities. Samples were gathered every two months, from five stations using a Surber sampler( 30×30cm), fixed in formalin (4%) and then separated and identified in the laboratory. Environmental conditions (current velocity, temperature, depth, width, dissolve oxygen...
Functional diversity is increasingly identified as an important driver of ecosystem functioning. Various indices have been proposed to measure the functional diversity of a community, but there is still no consensus on which are most suitable. Indeed, none of the existing indices meets all the criteria required for general use. The main criteria are that they must be designed to deal with sever...
recognizing the herbaceous plant species diversity could use as an importantindicator applied for the rangeland and forests management. considering the presence ofvegetation and animal husbandry in zagros region, iran, being aware of the diversity andrichness of plant species is necessary to management or the destructed vegetationrestoration. in order to study the effect of aspect and elevation...
In order to investigate the effects of range management plans on species diversity, richness and evenness in Semirum rangelands, 52 sites (28 with treated plan and 24 without treated plan) were selected. The non-parametric indices for species richness (Margalof, Menhinick, Jacknife and counting method) and species diversity (Simpson, Camargo, Smith and Wilson and modified Nee) were compared in ...
in this study, species richness, evenness and vegetation biodiversity were investigated in stabilized and non-stabilized cut edge areas of chachkam district forest roads in sari forest of iran. 18 micro plots 1×1m (36 micro plots) were sampled to carry out this research on two cut edge areas. number of trees, shrubs and herbaceous were recorded in each micro-plot. significant difference was inv...
Recognizing the herbaceous plant species diversity could use as an importantindicator applied for the rangeland and forests management. Considering the presence ofvegetation and animal husbandry in Zagros region, Iran, being aware of the diversity andrichness of plant species is necessary to management or the destructed vegetationrestoration. In order to study the effect of aspect and elevation...
Species diversity protection will ensure the protection of natural processes and ecological values. Appropriate information on the condition and location of endanger species will facilitate the management and conservation of forest areas. The present study was conducted in Arasbaran forests for the purpose of evaluating two sampling methods including circular sampling (1000 m2 area) and the nea...
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