نتایج جستجو برای: indices of evenness
تعداد نتایج: 21168485 فیلتر نتایج به سال:
Immigration flows and social inequalities reflect increased multi-ethnic segregation in contemporary urban Europe. For a better understanding of these processes, the present study investigates main strengths multi-group residential indices, testing sensitivity reliability under different metropolitan contexts five European countries. These indices focus on research dimensions approach conceptua...
the predatory mites of suborder prostigmata are important natural enemies of spider mites. in this study abundance and biodiversity of predatory mites of super families of raphignathoidea, bdelloidea and erythraeoidea in pomefruit orchards of mashhad) educational orchard of agricultural college of ferdowsi unuversity of mashhad, agricultural research centre of torogh and laeen, torghabe and sha...
evaluation of range conditions and plant diversity circumstances can help to rangeland managers who establish their managerial approaches on the basis of ecological capabilities of rangeland ecosystems. hence, surveying of rangelands was done in four sites of northern alborz mt. including western alborz (masooleh site), west to middle alborz (javaherdeh site), central area (polour site), and ea...
Biodiversity, a multidimensional property of natural systems, is difficult to quantify partly because of the multitude of indices proposed for this purpose. Indices aim to describe general properties of communities that allow us to compare different regions, taxa, and trophic levels. Therefore, they are of fundamental importance for environmental monitoring and conservation, although there is n...
The research was conducted by observing the plankton biota, especially in interaction and relationship between riverine biota environmental factors. Plankton enable to provide an indication of changes determining diversity (H’) evenness (e) indices. sampling carried out at 4 stations with different conditions. were sampled using filtering method analysed based on their evenness. Besides, analys...
the influence of long-term mixed organic and inorganic contamination on soil microbial activity, community structure and genetic diversity was investigated in soil samples from a coke oven plant located in upper silesia, poland. the tested soils were heavily contaminated with polycyclic aromatic hydrocarbons (pahs) and heavy metals. the microbial communities were characterized using the phospho...
Biodiversity is declining worldwide from reductions in both species richness and evenness. Field experiments have shown that primary productivity is often reduced when richness of plant species is lowered. However, experiments testing richness effects have used evenness levels that are much higher than normally encountered in plant communities and have been based on the assumption that species ...
This study was undertaken to investigate the role of forest management in tree diversity, regeneration and vegetation in control and managed parcels of series No. 1 of forestry plan in Khalil-Mahale, Behshahr. Thirty samples with an area of 1000 m2 were systematically and randomly taken with a 100 × 75 m grid in both parcels. In each plot, tree number and species type were recorded. In order to...
The design of road surfaces involves application a sophisticated algorithm system based on mathematical calculations and engineering solutions, with the calculation evaluation criteria. It is precisely observance standardized requirements in terms criteria that makes it possible to consider pavement as reliable, safe convenient for traffic during specified service life. When calculating strengt...
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