Fréville Hélène, McConway Kevin, Dodd Mike, Silvertown Jonathan
Ecology and Evolution Research Group, Department of Biological Sciences, Open University, Walton Hall, Milton Keynes, MK7 6AA, United Kingdom.
Ecology. 2007 Oct;88(10):2662-72. doi: 10.1890/06-1453.1.
The global extinction of species proceeds through the erosion of local populations. Using a 60-year time series of annual sighting records of plant species, we studied the correlates of local extinction risk associated with a risk of species extinction in the Park Grass Experiment where plants received long-term exposure to nutrient enrichment, soil acidification, and reductions in habitat size. We used multivariate linear models to assess how extrinsic threats and life history traits influence extinction risk. We investigated effects of four extrinsic threats (nitrogen enrichment, productivity, acidification, and plot size) as well as 11 life history traits (month of earliest flowering, flowering duration, stress tolerance, ruderalness [plant species' ability to cope with habitat disturbance], plant height, diaspore mass, seed bank, life form, dispersal mode, apomixis [the ability for a species to reproduce asexuall through seeds], and mating system). Extinction risk was not influenced by plant family. All of the 11 life history traits except life form and all threat variables influenced extinction risk but always via interactions which typically involved one threat variable and one life history trait. We detected comparatively few significant interactions between life history traits, and the interacting traits compensated for each other. These results suggest that simple predictions about extinction risk based on species' traits alone will often fail. In contrast, understanding the interactions between extrinsic threats and life history traits will allow us to make more accurate predictions of extinctions.
物种的全球灭绝是通过当地种群的消亡来实现的。利用一个长达60年的植物物种年度观测记录时间序列，我们在公园草地实验中研究了与物种灭绝风险相关的当地灭绝风险的相关因素，在该实验中，植物长期暴露于养分富集、土壤酸化和栖息地面积减小的环境中。我们使用多元线性模型来评估外部威胁和生活史特征如何影响灭绝风险。我们调查了四种外部威胁（氮富集、生产力、酸化和样地大小）以及11种生活史特征（最早开花月份、开花持续时间、耐胁迫能力、杂草性[植物物种应对栖息地干扰的能力]、株高、传播体质量、种子库、生活型、传播方式、无融合生殖[物种通过种子进行无性繁殖的能力]和交配系统）的影响。灭绝风险不受植物科的影响。除生活型外的所有11种生活史特征以及所有威胁变量都影响灭绝风险，但总是通过通常涉及一个威胁变量和一个生活史特征的相互作用来实现。我们检测到生活史特征之间相对较少的显著相互作用，并且相互作用的特征相互补偿。这些结果表明，仅基于物种特征对灭绝风险进行简单预测往往会失败。相比之下，了解外部威胁和生活史特征之间的相互作用将使我们能够更准确地预测灭绝情况。
