نتایج جستجو برای: index species
تعداد نتایج: 931450 فیلتر نتایج به سال:
Drought and grazing rangelands play an important role in changing the structure of vegetation and losing the biodiversity of natural ecosystems. In this research, in order to determine the effects of drought and livestock grazing on the vegetation structure of rangelands located in the Nakhab Forest of South Khorasan Province, species abundance, biodiversity, and range condition and trend were ...
Conservation priority setting based on phylogenetic diversity has frequently been proposed but rarely implemented. Here, we define a simple index that measures the contribution made by different species to phylogenetic diversity and show how the index might contribute towards species-based conservation priorities. We describe procedures to control for missing species, incomplete phylogenetic re...
Development of a green belt with suitable plant species around the source of emission can mitigate the atmospheric contamination. Selection of such plant species are required to combat air pollution based on their tolerance level. Present study was undertaken to evaluate the tolerance level of higher plants in East of Esfahan city, Iran, during 2011 in terms of assessing Air Pollution Tolerance...
This study concerns the cytotaxonomic investigations on twelve species belonging to three sections from the genus Vicia in Iran. A taxonomic background of the genus is given in brief. The previous counts reported for the genus in Index to plant chromosome number are summarized. In addition to one new count, the chromosome numbers of four species are reported for the first time. Briefly, the ...
The research design of elimination trail has performed in the form of randomized completely blocks design with 3 replications and 8 treatments ( species of needleleaves) in Kohsarkande forests of Neka, Mazandaran(North of Iran). For investigation of the plant biodiversity the treatments of needleleaves in this elimination trail, the aforestation of hard woods(Maple) and the bare area were sel...
Mites are the best representative of soil arthropods because they are the most diverse in terms of ecological niche and behavior. In this study, abundance and biodiversity of laelapid soil mites were evaluated in eight sites in Saman and Shahrekord, with each site including an orchard and a farmland. There was a significant difference in the Shannon-Wiener diversity index of laelapid mites amon...
in order to evaluate the yield and advantage of two- and three-species intercropping of sunflower with corn and soybean, an experiment was conducted at the research farm of faculty of agriculture of tabriz university in tabriz, iran 2011. the experiment was arranged based on randomized completely block design with 6 treatments and three replications. treatments were included the pure stand of s...
this research was investigated to evaluate growth indices and competitive ability of two wheat ) triticum aestivum l. (cultivars in interference with two species of narrow and broad leaf weeds as two separated experiments based on a randomized complete block design with three replications at agricultural faculty of bu-ali sina university, during 2008-2009. in both experiments, alvand and sayson...
the diversity and abundance of bees associated with alfalfa and onion fields in mashhad and chenaran were evaluated from mid june until late october 2010. considering the type and flowering period of the studied crops, by using a standard sweeping net, either a weekly or biweekly sampling program of apoid bees were carried out in selected fields for both crops. as a result, 17 species of 15 gen...
Understanding species diversity and disturbance relationships is important for biodiversity conservation in disturbance-driven boreal forests. Species richness and evenness may respond differently with stand development following fire. Furthermore, few studies have simultaneously accounted for the influences of climate and local site conditions on species diversity. Using forest inventory data,...
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