نتایج جستجو برای: and evenness e

تعداد نتایج: 17333637  

Journal: :PLoS ONE 2009
Andrew H. Altieri Geoffrey C. Trussell Patrick J. Ewanchuk Genevieve Bernatchez Matthew E. S. Bracken

BACKGROUND Our understanding of the functional consequences of changes in biodiversity has been hampered by several limitations of previous work, including limited attention to trophic interactions, a focus on species richness rather than evenness, and the use of artificially assembled communities. METHODOLOGY AND PRINCIPAL FINDINGS In this study, we manipulated the density of an herbivorous ...

Journal: :مرتع و آبخیزداری 0
جواد معتمدی (ترکان) استادیار گروه مرتع و آبخیزداری، دانشکده منابع طبیعی دانشگاه ارومیه اسماعیل شیدای کرکج دانشجوی دکتری علوم مرتع دانشگاه علوم کشاورزی و منابع طبیعی گرگان

species diversity is one of the important characteristics shows rangeland ecosystems changes, which isalready under effects of management practices. thus, this research was conducted to study speciesdiversity variation and assess suitable distributive abundance model in three rangeland sites in westazerbaijan. these sites were almost similar in environmental properties and differ in view point ...

2015
M. Choudhury

Moth species were studied from some selected districts of Assam (i.e., Cachar and Barpeta district) to determine their diversity index, species richness and evenness of Arctiidae and Geometriidae family of the moth fauna.The moths were collected by applying specialized trapping methods using UV light operating during night. Collected moth species were identified up to family-genusspecies level....

Journal: :Journal of the Textile Machinary Society 1953

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: :Proceedings. Biological sciences 2015
Heloise Gibb Nathan J Sanders Robert R Dunn Simon Watson Manoli Photakis Silvia Abril Alan N Andersen Elena Angulo Inge Armbrecht Xavier Arnan Fabricio B Baccaro Tom R Bishop Raphael Boulay Cristina Castracani Israel Del Toro Thibaut Delsinne Mireia Diaz David A Donoso Martha L Enríquez Tom M Fayle Donald H Feener Matthew C Fitzpatrick Crisanto Gómez Donato A Grasso Sarah Groc Brian Heterick Benjamin D Hoffmann Lori Lach John Lattke Maurice Leponce Jean-Philippe Lessard John Longino Andrea Lucky Jonathan Majer Sean B Menke Dirk Mezger Alessandra Mori Thinandavha C Munyai Omid Paknia Jessica Pearce-Duvet Martin Pfeiffer Stacy M Philpott Jorge L P de Souza Melanie Tista Heraldo L Vasconcelos Merav Vonshak Catherine L Parr

Many studies have focused on the impacts of climate change on biological assemblages, yet little is known about how climate interacts with other major anthropogenic influences on biodiversity, such as habitat disturbance. Using a unique global database of 1128 local ant assemblages, we examined whether climate mediates the effects of habitat disturbance on assemblage structure at a global scale...

Journal: :Journal of the Textile Machinary Society 1953

2011
Lars Gamfeldt Helmut Hillebrand

The study of the interrelationship between productivity and biodiversity is a major research field in ecology. Theory predicts that if essential resources are heterogeneously distributed across a metacommunity, single species may dominate productivity in individual metacommunity patches, but a mixture of species will maximize productivity across the whole metacommunity. It also predicts that a ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Devra I Jarvis Anthony H D Brown Pham Hung Cuong Luis Collado-Panduro Luis Latournerie-Moreno Sanjaya Gyawali Tesema Tanto Mahamadou Sawadogo Istvan Mar Mohammed Sadiki Nguyen Thi-Ngoc Hue Luis Arias-Reyes Didier Balma Jwala Bajracharya Fernando Castillo Deepak Rijal Loubna Belqadi Ram Rana Seddik Saidi Jeremy Ouedraogo Roger Zangre Keltoum Rhrib Jose Luis Chavez Daniel Schoen Bhuwon Sthapit Paola De Santis Carlo Fadda Toby Hodgkin

Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richnes...

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