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Extinction risk and diversification are linked in a plant biodiversity hotspot
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نویسنده
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davies t.j. ,smith g.f. ,bellstedt d.u. ,boatwright j.s. ,bytebier b. ,cowling r.m. ,forest f. ,harmon l.j. ,muasya a.m. ,schrire b.d. ,steenkamp y. ,van der bank m. ,savolainen v.
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منبع
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plos biology - 2011 - دوره : 9 - شماره : 5
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چکیده
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It is widely recognized that we are entering an extinction event on a scale approaching the mass extinctions seen in the fossil record. present-day rates of extinction are estimated to be several orders of magnitude greater than background rates and are projected to increase further if current trends continue. in vertebrates,species traits,such as body size,fecundity,and geographic range,are important predictors of vulnerability. although plants are the basis for life on earth,our knowledge of plant extinctions and vulnerabilities is lagging. here,we disentangle the underlying drivers of extinction risk in plants,focusing on the cape of south africa,a global biodiversity hotspot. by comparing red list data for the british and south african floras,we demonstrate that the taxonomic distribution of extinction risk differs significantly between regions,inconsistent with a simple,trait-based model of extinction. using a comprehensive phylogenetic tree for the cape,we reveal a phylogenetic signal in the distribution of plant extinction risks but show that the most threatened species cluster within short branches at the tips of the phylogeny-opposite to trends in mammals. from analyzing the distribution of threatened species across 11 exemplar clades,we suggest that mode of speciation best explains the unusual phylogenetic structure of extinction risks in plants of the cape. our results demonstrate that explanations for elevated extinction risk in plants of the cape flora differ dramatically from those recognized for vertebrates. in the cape,extinction risk is higher for young and fast-evolving plant lineages and cannot be explained by correlations with simple biological traits. critically,we find that the most vulnerable plant species are nonetheless marching towards extinction at a more rapid pace but,surprisingly,independently from anthropogenic effects. our results have important implications for conservation priorities and cast doubts on the utility of current red list criteria for plants in regions such as the cape,where speciation has been rapid,if our aim is to maximize the preservation of the tree-of-life. © 2011 davies et al.
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آدرس
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national center for ecological analysis and synthesis,university of california,santa barbara,ca,united states,department of biology,mcgill university,montreal,qc, Canada, south african national biodiversity institute,biosystematics research and biodiversity collections,pretoria,south africa,schweickerdt herbarium,department of plant science,university of pretoria,pretoria, South Africa, department of biochemistry,university of stellenbosch,stellenbosch, South Africa, compton herbarium,south african national biodiversity institute,cape town,south africa,department of botany and plant biotechnology,university of johannesburg,johannesburg, South Africa, department of biochemistry,university of stellenbosch,stellenbosch,south africa,bews herbarium,school of biological and conservation sciences,university of kwazulu-natal,pietermaritzburg, South Africa, botany department,nelson mandela metropolitan university,port elizabeth, South Africa, royal botanic gardens,kew,richmond,surrey, United Kingdom, department of biological sciences,university of idaho,moscow,id, United States, department of botany and bolus herbarium,university of cape town,western cape,rondebosch, South Africa, royal botanic gardens,kew,richmond,surrey, United Kingdom, south african national biodiversity institute,biosystematics research and biodiversity collections,pretoria, South Africa, department of botany and plant biotechnology,university of johannesburg,johannesburg, South Africa, royal botanic gardens,kew,richmond,surrey,united kingdom,imperial college london,silwood park campus,ascot,berkshire, United Kingdom
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Authors
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