Extinction risk and diversification are linked in a plant biodiversity hotspot.
Extinction risk and diversification are linked in a plant biodiversity hotspot.
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DOI：
10.1371/journal.pbio.1000620
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发表时间：
2011-05
期刊：
影响因子：
9.8
通讯作者：
Savolainen V
中科院分区：
文献类型：
--
作者：
Davies TJ;Smith GF;Bellstedt DU;Boatwright JS;Bytebier B;Cowling RM;Forest F;Harmon LJ;Muasya AM;Schrire BD;Steenkamp Y;van der Bank M;Savolainen V
南非开普敦的植物灭绝风险与全球脊椎动物的风险不同，年轻和快速进化的植物谱系以最快的速度走向灭绝，但独立于人类的影响。人们普遍认为，我们正在进入一个规模接近化石记录中看到的大规模灭绝事件。据估计，目前的灭绝率比背景灭绝率高出几个数量级，如果目前的趋势继续下去，预计还会进一步增加。在脊椎动物中，物种特征，如身体大小，繁殖力和地理范围，是脆弱性的重要预测因素。尽管植物是地球上生命的基础，但我们对植物灭绝和脆弱性的了解却很滞后。在这里，我们解开了植物灭绝风险的潜在驱动因素，重点是南非角，一个全球生物多样性热点。通过比较英国和南非植物区系的红色名录数据，我们证明了灭绝风险的分类学分布在不同地区之间存在显着差异，这与简单的基于特征的灭绝模型不一致。使用一个全面的系统发育树的好望角，我们揭示了植物灭绝风险的分布中的系统发育信号，但最受威胁的物种集群内的短分支的尖端，在哺乳动物相反的趋势。通过分析11个典型分支中受威胁物种的分布，我们认为物种形成模式最能解释开普敦植物中灭绝风险的不寻常系统发育结构。我们的研究结果表明，对开普植物群植物灭绝风险升高的解释与脊椎动物的解释有很大不同。在好望角，年轻和快速进化的植物谱系的灭绝风险较高，不能用简单的生物学特征来解释。至关重要的是，我们发现，最脆弱的植物物种仍然在以更快的速度走向灭绝，但令人惊讶的是，独立于人为影响。我们的研究结果具有重要的意义，保护的优先事项，并投下怀疑的效用，目前的红色名录标准的植物在该地区，如好望角，那里的物种形成已经迅速，如果我们的目标是最大限度地保护树的生命。生物多样性的迅速丧失是我们今天面临的最重大的生态挑战。在过去的几年里，国际自然保护联盟发布了红色名录，记录了物种灭绝的无情下滑;最近的损失包括夏威夷乌鸦，金蟾，海豚和西非黑犀牛。在哺乳动物等我们熟知的群体中，灭绝的风险与生物学有关，最脆弱的物种往往是大型的，繁殖缓慢，分布狭窄。虽然植物是地球上生命的基础，但我们对植物生长的驱动因素的了解却很少。在这里，我们解开植物生长的原因。我们表明，南非开普敦的植物灭绝风险的过程与脊椎动物更普遍的不同。最脆弱的物种存在于年轻和快速进化的植物谱系中，与脊椎动物的模式相反。我们的研究结果说明了物种形成和灭绝过程之间的复杂联系。我们还表明，最受威胁的物种正在以更快的速度走向灭绝，但令人惊讶的是，这种风险似乎与人类的影响无关。
Plant extinction risks in the Cape, South Africa differ from those for vertebrates worldwide, with young and fast-evolving plant lineages marching towards extinction at the fastest rate, but independently of human effects. 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. The rapid loss of biodiversity is the most significant ecological challenge we face today. Over the past few years, the International Union for Conservation of Nature has published Red Lists documenting the inexorable slide towards extinction of species; recent losses include the Hawaiian crow, golden toad, Baiji dolphin, and the West African black rhino. In groups we know well, such as mammals, the risk of extinction has been related to biology, with the most vulnerable species tending to be large, slow breeding, and narrowly distributed. Although plants are the basis for life on Earth, our knowledge of the drivers of plant extinctions is poor. Here, we disentangle the causes of plant extinctions. We show that the processes linked with extinction risks in plants of the Cape, South Africa differ from those for vertebrates more generally. The most vulnerable species are found within young and fast-evolving plant lineages, opposite to patterns in vertebrates. Our results illustrate the intricate link between the processes of speciation and extinction. We also show that the most threatened species are marching towards extinction at faster rates, but surprisingly, the risk appears independent of human effects.
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影响因子：
8.8
作者：
Fritz, Susanne A.;Bininda-Emonds, Olaf R. P.;Purvis, Andy
通讯作者：
Purvis, Andy
影响因子：
1
作者：
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通讯作者：
van der Bank, Michelle
DOI：
10.1098/rspb.1997.0057
发表时间：
1997-03-22
影响因子：
4.7
作者：
Bennett, PM;Owens, IPF
通讯作者：
Owens, IPF
DOI：
10.1073/pnas.0510541103
发表时间：
2006-03-14
影响因子：
11.1
作者：
Cardillo, M;Mace, GM;Purvis, A
通讯作者：
Purvis, A
影响因子：
4.8
作者：
Freville, Helene;McConway, Kevin;Silvertown, Jonathan
通讯作者：
Silvertown, Jonathan