Srinivasan U Thara, Dunne Jennifer A, Harte John, Martinez Neo D
Energy and Resources Group, 310 Barrows Hall, University of California, Berkeley, California 94720, USA.
Ecology. 2007 Mar;88(3):671-82. doi: 10.1890/06-0971.
Although an ecosystem's response to biodiversity loss depends on the order in which species are lost, the extinction sequences generally used to explore such responses in food webs have been ecologically unrealistic. We investigate how several extinction orders affect the minimum number of secondary extinctions expected within pelagic food webs from 34 temperate freshwater lakes. An ecologically plausible extinction order is derived from the geographically nested pattern of species composition among the lakes and is corroborated by species' pH tolerances. Simulations suggest that lake communities are remarkably robust to this realistic extinction order and highly sensitive to the reverse sequence of species loss. This sensitivity is not well explained by the known sensitivity of networks to the loss of highly connected species but appears to be better explained by our observation that trophic specialists preferentially consume widely distributed species at low risk of extinction. Our results highlight an important aspect of community organization that may help to maintain biodiversity amidst changing environments.
尽管生态系统对生物多样性丧失的反应取决于物种丧失的顺序，但通常用于探索食物网中此类反应的灭绝序列在生态学上并不现实。我们研究了几种灭绝顺序如何影响来自34个温带淡水湖的浮游食物网中预期的二次灭绝的最小数量。一种生态学上合理的灭绝顺序源自湖泊间物种组成的地理嵌套模式，并得到物种pH耐受性的证实。模拟表明，湖泊群落对这种现实的灭绝顺序具有显著的抗性，而对物种丧失的反向序列高度敏感。这种敏感性不能很好地用已知的网络对高连接度物种丧失的敏感性来解释，但似乎可以更好地用我们的观察结果来解释，即营养专家优先消耗分布广泛且灭绝风险低的物种。我们的结果突出了群落组织的一个重要方面，这可能有助于在不断变化的环境中维持生物多样性。
