نتایج جستجو برای: diversity indices

تعداد نتایج: 268614  

2004
Ian R. Swingland

biodiversity/biological diversity Species, genetic, and ecosystem diversity in an area, sometimes including associated abiotic components such as landscape features, drainage systems, and climate. diversity indices Measures that describe the different components of biodiversity, such as species richness (alpha diversity), beta and gamma diversity, endemicity, and higher taxon richness. ecosyste...

2013
Gebriel M. Shamia

The Improved Generalized Diversity Index (IGDI) has been proposed as a tool that can be used to identify areas that have high conservation value and measure the ecological condition of an area. IGDI is based on the species relative abundances. This paper is concerned with particular attention is given to comparisons involving the MacArthur model of species abundances. The properties and perform...

ژورنال: علوم آب و خاک 2014

Comparison of the land suitability variations among the soil map units in viewpoint of pedodiversity indices may provide a good assessment of the soil mapping precision. The main objective of this study was to assess the significance of functional pedodiversity thorough two detailed map units for irrigated wheat and potato for class and subclass levels of suitability in the Faradonbeh plain, us...

Journal: :محیط زیست طبیعی 0
حمزه جعفری سرابی دانشجوی کارشناسی ارشد جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران بابک پیله ور استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران غلامحسین ویس کرمی کارشناس ارشد علوم گیاهی، سیستماتیک گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران جواد سوسنی استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران

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...

2003
Thomas O. Crist Joseph A. Veech Jon C. Gering Keith S. Summerville

Species diversity may be additively partitioned within and among samples (a and b diversity) from hierarchically scaled studies to assess the proportion of the total diversity (g) found in different habitats, landscapes, or regions. We developed a statistical approach for testing null hypotheses that observed partitions of species richness or diversity indices differed from those expected by ch...

2015
Patrick L. Thompson T. Jonathan Davies Andrew Gonzalez

In experimental systems, it has been shown that biodiversity indices based on traits or phylogeny can outperform species richness as predictors of plant ecosystem function. However, it is unclear whether this pattern extends to the function of food webs in natural ecosystems. Here we tested whether zooplankton functional and phylogenetic diversity explains the functioning of 23 natural pond com...

2016
Elpida K. Karadimou Athanasios S. Kallimanis Ioannis Tsiripidis Panayotis Dimopoulos

The relationship between species richness and area is one of the few well-established laws in ecology, and one might expect a similar relationship with functional diversity (FD). However, only a few studies investigate the relationship between trait-based FD and area, the Functional Diversity - Area Relationship (FDAR). To examine FDAR, we constructed the species accumulation curve and the corr...

2015
Samira Mobaied Nathalie Machon Emmanuelle Porcher

The biological diversity of the Earth is being rapidly depleted due to the direct and indirect consequences of human activities. Specialist or rare species are generally thought to be more extinction prone than generalist or common species. Testing this assumption however requires that the rarity and ecological specialization of the species are quantified. Many indices have been developed to cl...

Journal: :Bioinformatics 2014
Josep Gregori Miquel Salicru Esteban Domingo Alex Sánchez-Pla Juan I. Esteban Francisco Rodríguez-Frías Josep Quer

Given the inherent dynamics of a viral quasispecies, we are often interested in the comparison of diversity indices of sequential samples of a patient, or in the comparison of diversity indices of virus in groups of patients in a treated versus control design. It is then important to make sure that the diversity measures from each sample may be compared with no bias and within a consistent stat...

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