نتایج جستجو برای: extinction of rare species

تعداد نتایج: 21217683  

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2014
Ronald Sandler

There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new va...

2016
Weini Huang Paulo Roberto de Araujo Campos Viviane Moraes de Oliveira Fernando Fagundes Ferrreira

The maintenance of species diversity is a central focus in ecology. It is not rare to observe more species than the number of limiting resources, especially in plankton communities. However, such high species diversity is hard to achieve in theory under the competitive exclusion principles, known as the plankton paradox. Previous studies often focus on the coexistence of predefined species and ...

Journal: :Mathematical biosciences 2009
Ling-ling Chen Cang Hui Z S Lin

Habitat destruction, often caused by anthropogenic disturbance, can lead to the extinction of species at an unprecedented rate. It is important, therefore, to consider habitat destruction when assessing population viability. Another factor often ignored in population viability analysis, is the Allee effect that adds to the risk of populations already on the verge of extinction. Understanding th...

2013
Benjamin Bergerot Bernard Hugueny Jérôme Belliard

BACKGROUND Predicting which species are likely to go extinct is perhaps one of the most fundamental yet challenging tasks for conservation biologists. This is particularly relevant for freshwater ecosystems which tend to have the highest proportion of species threatened with extinction. According to metapopulation theories, local extinction and colonization rates of freshwater subpopulations ca...

Journal: :Ecology 2006
Mark Vellend Kris Verheyen Hans Jacquemyn Annette Kolb Hans Van Calster George Peterken Martin Hermy

Following habitat fragmentation individual habitat patches may lose species over time as they pay off their "extinction debt." Species with relatively low rates of population extinction and colonization ("slow" species) may maintain extinction debts for particularly prolonged periods, but few data are available to test this prediction. We analyzed two unusually detailed data sets on forest plan...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده ادبیات و زبانهای خارجی 1390

august wilson is undoubtedly one of the rare black playwrights whose works have attracted streams of attention and worldwide audience. the present study aims at analyzing fences and piano lesson which are two of the most successful plays in his pittsburgh cycle from the perspective of michel foucault’s theories and ideas. studying these two plays from foucault’s perspective opens new windows in...

Journal: :Acta Brasiliensis 2022

The present study aimed to update the categorization of extinction risk Discocactus bahiensis Britton & Rose and zehntneri Rose, endemic Cactaceae species from Northeastern Brazil. georeferenced occurrence points were obtained online databases speciesLink Global Biodiversity Information Facility (GBIF). Polygons traced using these points, being gridded with 4 km² cells virtually divided in ...

قهساره اردستان, الهام, ترکش, مصطفی , مهدی, بصیری, وهابی, محمدرضا ,

With regard to retrogression trend of rangelands in central Zagross, many native plant species are expected to be increasingly on the verge of extinction. Therefore, for proper rangeland management the optimum harvest intensity of important plant species is an essential factor for rehabilitation and recovery of native rangeland species. This research was aimed to study the response of four rang...

2017
Anna Tovo Samir Suweis Marco Formentin Marco Favretti Igor Volkov Jayanth R Banavar Sandro Azaele Amos Maritan

The quantification of tropical tree biodiversity worldwide remains an open and challenging problem. More than two-fifths of the number of worldwide trees can be found either in tropical or in subtropical forests, but only ≈0.000067% of species identities are known. We introduce an analytical framework that provides robust and accurate estimates of species richness and abundances in biodiversity...

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