نتایج جستجو برای: species diversity index
تعداد نتایج: 1072319 فیلتر نتایج به سال:
background : cockroaches are found as the most common urban pests of tropical countries, prompting economic and serious health risk problem for humans by carrying microbes and allergens, acting as vector for various pathogens of diseases. the present study was conducted from april 2013 to march 2014 in various human dwelling localities of urban area of district lahore, pakistan. methods : coc...
fish species diversity, distribution and abundance were studied in the sardabrud and chalus rivers, in the southern caspian sea basin, during 1992 and 1993 in five and four stations respectively, by monthly collections using electrofishing device. in total, 3200 fish specimens, including 15 species in sardabrud river and 12 species in chalus river, were investigated. the fish comprised of 13 ge...
Habitat heterogeneity plays an important role in increasing species diversity. Heterogeneity of habitats and protected areas can increase the ability of species to adapt to climate change. It is expected that appropriate heterogeneity is necessary for sustainability of protected areas. The influence of altitude on parameters such as temperature and precipitation and the role of microclimates in...
road construction is one of the effective factors for ecological changes which affects diversity and species composition in forest roads edges. this research was performed in kheirud forest to evaluate herbaceous diversity and tree regeneration establishment in different distances from road edge. for this purpose, we sampled herbaceous and tree species regeneration in 0,5,10,25, 50 and 100 m di...
assessment of diversity and species richness in the understanding of ecosystem functions, protect and preserve genetic resources, evaluation and control of environmental change and the success or failure will help natural resource management programs. arbitrary banning livestock grazing program and one of the most common and perhaps the most degraded pastures and reduced the diversity and speci...
introduction the complexity of natural ecosystem, as the rangelands, is caused to propose the different approaches toevaluatethe ecosystem on the basis of sustainable and systematic management. study on the interaction connectionsbetween plants and biotic and abiotic factors in the rangeland ecosystem can be achieved by relationsofmanagerial strategies in order to conduct the rangeland health. ...
The tree species diversity in mixed stands of beech and valuable broadleaves was researched in the area of the National Park `Djerdap` on fifteen sample plots (total study area of about 5 ha). For this purpose, the following diversity measures were applied: (1) Shannon`s index H', (2) Simpson`s index (Simpson 1949), (3) McIntosh`s diversity index D' (McIntosh 1967), (4) Hill’s N1 diversity numb...
Snow-fed river Pinder -a tributary of river Alaknanda in central Himalaya was explored for fish assemblages and habitat specificity. Altogether 27 fish species were reported from three orders, four families and nine genera. Cypriniformes order was dominating followed by Siluriformes and Salmoniformes. Shannon-Weiner diversity index (3.09 to 4.10) and Simpson index of diversity (0.81 to 0.92) of...
This study aims to identify and determine species diversity and richness of the Gastropods of intertidal zone of Bushehr seaport coastal field and assess ecological status of the area using Welch index. Sampling was carried out at 6 stations in Bushehr seaport in winter and summer seasons during 2013-2014. Sampling bed sediments was done three times in each station and Gastropod samples were co...
As troves of microbiome sequencing data provide improved resolution of patterns of microbial diversity, new approaches are needed to understand what controls these patterns. Many microbial ecologists are using cultivated model microbial communities to address this challenge. These systems provide opportunities to identify drivers of microbiome assembly, but key challenges and limitations need t...
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