نتایج جستجو برای: species diversity index
تعداد نتایج: 1072319 فیلتر نتایج به سال:
We introduce a new dominance concept consisting of three new dominance metrics based on Lloyd’s (1967) mean crowding index. The new metrics link communities and species, whereas existing ones are applicable only to communities. Our community-level metric is a function of Simpson’s diversity index. For species, our metric quantifies the difference between community dominance and the dominance of...
the seasonal diversity and distribution of microphytes and macrophytes in 40 artificial irrigationponds constructed in a semi-arid region, and the most suitable conditions to maintain these enclaves asbiodiversity spots were studied for the first time. a total of 104 species were detected. bacillariophyta,cyanobacteria and chlorophyta dominated both pelagic and benthic microphytic communities, ...
Knowledge of the relationships between biotic components of rangeland ecosystem i.e. herbivores and plants is important for range managers. In order to study herbivorse grazing intensity on plant species diversity, an experiment was conductef using fuor grazing treatments in darrehshar rangelands, Ilam province in 2015. Plant species data were taken based on a randomized-systematic sampling met...
Chamomile (Matricaria chamomilla), an important medicinal plant belonging to the Asteraceae family, has a wide distribution in Iran and other parts of the world. The medicinal and pharmacological effects of chamomile are mainly associated with its essential oil content and it is widely used in food, cosmetics and pharmaceutical industries. Despite its wide geographical distribution in Iran, lit...
The influence of climatic and pollution gradients was determined on species richness, species diversity, and values of phytoindicators of the herb layer in pine and mixed pine forest communities in Poland. Geographical longitude was used as a synthetic measure of geographical position. Ellenberg’s indices were used as synthetic measures of habitat differentiation, calculated as weighed averages...
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...
Measurement of Diversity Indices of Avian Communities at Taunsa Barrage Wildlife Sanctuary, Pakistan
The study was conducted to measure bird species diversity at Taunsa Barrage Wildlife Sanctuary from 2009 to 2011. The objective of the study was to identify avian diversity and main threats to them in the sanctuary. Data were collected by direct census method. In total, 58,598 bird species belonging to 53 families and 171 species were recorded. Density of the birds was 6.9 birds per hectare. Sh...
chamomile (matricaria chamomilla), an important medicinal plant belonging to the asteraceae family,has a wide distribution in iran and other parts of the world. the medicinal and pharmacological effects ofchamomile are mainly associated with its essential oil content and it is widely used in food, cosmetics andpharmaceutical industries. despite its wide geographical distribution in iran, little...
Aquatic macroinvertebrates, which play a significant role in the food chain of an ecosystem, are used in fresh water quality assessment to identify the environmental stress resulting from a variety of anthropogenic disturbances. Seasonal surveys of macroinvertebrate communities were conducted from April 2013 to March 2014 in Chhariganga oxbow lake of Nadia District of West Bengal, an eastern st...
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