نتایج جستجو برای: species evenness

تعداد نتایج: 548668  

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...

2016
Daniel Wohlgemuth Martin Solan Jasmin A. Godbold

The ecological consequences of species loss are widely studied, but represent an end point of environmental forcing that is not always realised. Changes in species evenness and the rank order of dominant species are more widespread responses to directional forcing. However, despite the repercussions for ecosystem functioning such changes have received little attention. Here, we experimentally a...

Journal: :Biological Journal of the Linnean Society 1996

Journal: :بوم شناسی کشاورزی 0
روح اله مرادی مسعود سامی

sustainability of productions in agricultural ecosystems depends on conservation and amplification of biodiversity. this study was conducted to determine the planting area, species richness, species evenness and biodiversity of different agronomical, horticultural and livestock productions in kerman province. for this purpose, information about planting area of agronomical and horticultural pla...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Helmut Hillebrand Daniel S Gruner Elizabeth T Borer Matthew E S Bracken Elsa E Cleland James J Elser W Stanley Harpole Jacqueline T Ngai Eric W Seabloom Jonathan B Shurin Jennifer E Smith

Consumer and resource control of diversity in plant communities have long been treated as alternative hypotheses. However, experimental and theoretical evidence suggests that herbivores and nutrient resources interactively regulate the number and relative abundance of coexisting plant species. Experiments have yielded divergent and often contradictory responses within and among ecosystems, and ...

2010
Carlos I. Espinosa Omar Cabrera Arantzazu L. Luzuriaga Adrián Escudero

This paper reports a study on species richness and composition of Tumbesian dry forest communities. We tested two alternative hypotheses about species assemblage processes in tropical dry forests: (1) species assemblage is determined by the filtering effect of environmental conditions and (2) species assemblage is determined by facilitative processes along the gradient of water availability, an...

2012
Hui Zhang Robert John Zechen Peng Jianli Yuan Chengjin Chu Guozhen Du Shurong Zhou

The relationship between species richness and evenness across communities remains an unsettled issue in ecology from both theoretical and empirical perspectives. As a result, we do not know the mechanisms that could generate a relationship between species richness and evenness, and how this responds to spatial scale. Here we examine the relationship between species richness(S) and evenness (Pie...

Journal: :The Journal of animal ecology 2011
Dale G Nimmo Simon G James Luke T Kelly Simon J Watson Andrew F Bennett

1. Patterns of species richness often correlate strongly with measures of energy. The more individuals hypothesis (MIH) proposes that this relationship is facilitated by greater resources supporting larger populations, which are less likely to become extinct. Hence, the MIH predicts that community abundance and species richness will be positively related. 2. Recently, Buckley & Jetz (2010, Jour...

2014
Carlo Ricotta Giovanni Bacaro Marco Moretti

Functional evenness is increasingly considered an important facet of functional diversity that sheds light on the complex relationships between community assembly and ecosystem functioning. Nonetheless, in spite of its relevant role for ecosystem functioning, only a few measures of functional evenness have been proposed. In this paper we introduce a new measure of functional evenness that refle...

Journal: :بوم شناسی کشاورزی 0
علیرضا باقری رضا قربانی محمد بنایان اول اورس شافنر

considering the importance of biodiversity conservation and protection assessment activities, the present filed study was conducted with aim to compare vegetation diversity of two areas with different levels of protection including ghorkhod protected area with seasonal grazing and golestan national park without grazing, during spring and summer of 2011. four replications were selected in each a...

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