نتایج جستجو برای: evenness sheldon index

تعداد نتایج: 398318  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده جنگلداری و مهندسی چوب و کاغذ 1391

درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...

2017
Zhengda Yu Hui Wang Jiao Meng Mingsheng Miao Qiang Kong Renqing Wang Jian Liu

Including or excluding rare taxa in bioassessment is a controversial topic, which essentially affects the reliability and accuracy of the result. In the present paper, we hypothesize that biological indices such as Shannon-Wiener index, Simpson's index, Margalef index, evenness, BMWP (biological monitoring working party), and ASPT (Average Score Per Taxon) respond differently to rare taxa exclu...

Journal: :Orphanet Journal of Rare Diseases 2009
Reha M Toydemir Michael J Bamshad

Sheldon-Hall syndrome (SHS) is a rare multiple congenital contracture syndrome characterized by contractures of the distal joints of the limbs, triangular face, downslanting palpebral fissures, small mouth, and high arched palate. Epidemiological data for the prevalence of SHS are not available, but less than 100 cases have been reported in the literature. Other common clinical features of SHS ...

Journal: :Ecology 2012
David W Crowder Tobin D Northfield Richard Gomulkiewicz William E Snyderi

Healthy ecosystems include many species (high richness) with similar abundances (high evenness). Thus, both aspects of biodiversity are worthy of conservation. Simultaneously conserving richness and evenness might be difficult, however, if, for example, the restoration of previously absent species to low densities brings a cost in reduced evenness. Using meta-analysis, we searched for benefits ...

2007
Thomas D. Olszewski Susan M. Kidwell

—The richness (number of species) and evenness (uniformity of species abundances) of death assemblages can differ from corresponding living communities due to processes such as between-habitat transport, environmental condensation, and differential taphonomic destruction. Analysis of 132 single-census live-dead comparisons of benthic molluscs from a variety of softbottom marine settings indicat...

Hamid Ahani, Hamid Jalilvand

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...

Journal: :The American naturalist 2008
Matthew R E Symonds Christopher N Johnson

Species richness and evenness are the two major components of biodiversity, but the way in which they are interrelated is a subject of contention. We found a negative relationship between the two variables for bird communities at 92 woodland sites across Australia and sought an explanation. Actual evapotranspiration (AET) was by far the best predictor of species richness. When AET was controlle...

Journal: :Jurnal Hama dan penyakit tumbuhan tropika 2023

In Indonesia, transgenic products are still considered innovative, and genetically modified (GM) maize has stayed on the market while its impact environmental biosafety is now being evaluated. Bt corn been recognized as one of solutions to problem Asian cob borers preserve production. Therefore, this study aimed investigate effect arthropod richness diversity in a limited testing field using ra...

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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