نتایج جستجو برای: indices of evenness
تعداد نتایج: 21168485 فیلتر نتایج به سال:
biodiversity plays a crucial role in stability and productivity of natural ecosystem. the main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. therefore, fifty different land unit tracts (lut) were identified in khod-neuk basin, yazd province, iran, in 2010. vegetation and soil samples were taken in th...
Biological diversity, also known as biodiversity, is an important criterion for measuring the value of an ecosystem. As biodiversity is closely related to human welfare and quality of life, many efforts to restore and maintain the biodiversity of species have been made by government agencies and non-governmental organizations, thereby drawing a substantial amount of international attention. In ...
Amplicon length heterogeneity PCR (LH-PCR) was investigated for its ability to distinguish between microbial community patterns from the same soil type under different land management practices. Natural sagebrush and irrigated mouldboard-ploughed soils from Idaho were queried as to which hypervariable domains, or combinations of 16S rRNA gene domains, were the best molecular markers. Using stan...
Background and objectives: In order to properly manage rangeland ecosystems, it is necessary to study the relationship between ecological factors in nature such as elevation, climate and soil factors with vegetation and living organisms. In this regard, the present study was conducted to investigate the relationship between species diversity and environmental factors (Physical and chemical char...
forest reserves are one of the most important approaches in ecosystem management in iran. in order to determine the effects of reserve management on plants diversity (woody plants and ground flora) in three zones (core zone, buffer zone, and transmission zone of chamhesar pear forest reserve), we mapped land form units. then 18 main sampling units (20×50=1000 m2) distributed randomly were chose...
rangeland ploughing and cultivation using dry land farming crops may be amajor reason for the destruction of natural resources in the semiarid and sub-humid regionswhich may significantly change the composition and reduce the stability of the affectedcommunities. in present research, an abandoned ploughed site was compared with a nearbyreference site in the semiarid rangelands of baharkish, quc...
A biodiversity investigation was carried out in the wild pistachio research forest located in southwest of Fars Province between 52˚ 30́́ to 52˚ 40́́ longitude and 29˚ to 29˚ 15́ latitude in an areaof 9374 Ha area. 72 sampling transects fifty meters long were designated using systematic-random design. In each sampling plot a list of bush, shrub, and tree species and their abundance were recorded. Th...
aim of this research was evaluated and compared of density (number tree per hectare), basal area and volume characteristics for estimation of tree species diversity in degraded forests. in order to, 73 hectares of kouhmian forests was inventory based on random systematic pattern with circular plots (10r and 26 plots). in each plot species, dbh and number of tree were measured and recorded. to e...
Forests are biologically diverse systems, representing some of the richest biological areas on Earth. They offer a variety of habitats for plants, animals and micro-organisms. However, forest biodiversity is increasingly threatened as a result of deforestation, fragmentation, climate change and other stressors. Biodiversity is the variation of life forms within a given ecosystem, biome, or on t...
Forests are biologically diverse systems, representing some of the richest biological areas on Earth. They offer a variety of habitats for plants, animals and micro-organisms. However, forest biodiversity is increasingly threatened as a result of deforestation, fragmentation, climate change and other stressors. Biodiversity is the variation of life forms within a given ecosystem, biome, or on t...
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