نتایج جستجو برای: diversity indices
تعداد نتایج: 268614 فیلتر نتایج به سال:
The composition of nematode communities (plant-parasitic and free-living) may be used as bioindicators of soil health or condition because composition correlates well with nitrogen cycling and decomposition, two critical ecological processes in soil. Maturity and trophic diversity indices withstand statistical rigor better than do abundances, proportions, or ratios of trophic groups. Maturity i...
Forestry plans have been influential on tree species and planting in different ways, regulating tree species diversity. Investigation of the changes in tree species diversity and preservation livestock sustainability by using forestry inventory can be an appropriate tool for decision makers in management. Indicators such as the Shannon Wiener and Simpson indices can be used to study the variati...
This study provides a baseline measure of pelagic fish species diversity around fish aggregating devices (FADs) in the Western Indian Ocean. Using data from visual censuses made by SCUBA divers around drifting FADs we (1) analysed 11 diversity indices describing 4 main components of pelagic diversity: number of species, evenness, taxonomic diversity and rarity and (2) discussed the viability of...
Forest degradation influences ecosystem sustainability and reduces plant species diversity. Plantations with coniferous trees in degraded ecosystems help the native species to become established and play a major role in preserving and improving plant diversity. This study aims at measuring and comparing the woody species diversity across different age classes of Pinus brutia and Cupressus horiz...
In a recent paper Warwick & Clarke (1995: Mar Ecol Prog Ser 129:301-305) introduced 2 new measures of community diversity, A and A' These measures dlffer from more conventional d~ver sity indices by incorporating the taxonomic relatedness of species into their calculation. In this paper we compare temporal trends in A and A' with more conventional diversity measures for the demersal fish commun...
The purpose of this study is to determine the woody species diversity in Sweet chestnut tree, Hazel-tree and Italian cypress ecosystems in the Guilan forests. A lozeng 0.5 ha sample plot was selectively established on each site. In the Sweet chestnut ecosystems , 4 sites were classified, whereas 10 sites of Hazel tree and Italian cypress ecosystems were classified based on species composition. ...
Realistic measures of biodiversity should reflect not only the relative abundances of species, but also the differences between them. We present a natural family of diversity measures taking both factors into account. This is not just another addition to the already long list of diversity indices. Instead, a single formula subsumes many of the most popular indices, including Shannon's, Simpson'...
Diversity represents a key concept in ecology, and there are various methods of assessing it. The multitude of diversity indices are quite puzzling and sometimes difficult to compute for a large volume of data. This paper promotes a computational tool used to assess the diversity of different entities. The BIODIV software is a user-friendly tool, developed using Microsoft Visual Basic. It is ca...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید