Department of Ecology and Evolutionary Biology, Rice University, Houston, TX, USA.
Ecol Lett. 2011 Jan;14(1):75-9. doi: 10.1111/j.1461-0248.2010.01558.x. Epub 2010 Nov 30.
Resolving how complexity affects stability of natural communities is of key importance for predicting the consequences of biodiversity loss. Central to previous stability analysis has been the assumption that the resources of a consumer are substitutable. However, during their development, most species change diets; for instance, adults often use different resources than larvae or juveniles. Here, we show that such ontogenetic niche shifts are common in real ecological networks and that consideration of these shifts can alter which species are predicted to be at risk of extinction. Furthermore, niche shifts reduce and can even reverse the otherwise stabilizing effect of complexity. This pattern arises because species with several specialized life stages appear to be generalists at the species level but act as sequential specialists that are hypersensitive to resource loss. These results suggest that natural communities are more vulnerable to biodiversity loss than indicated by previous analyses.
解决复杂性如何影响自然群落的稳定性对于预测生物多样性丧失的后果至关重要。以往稳定性分析的核心假设是消费者的资源是可替代的。然而，在其发育过程中，大多数物种会改变其食性；例如，成年动物通常使用的资源与幼虫或幼体不同。在这里，我们表明，这种个体发生的生态位转移在真实的生态网络中很常见，考虑到这些转移可以改变哪些物种有灭绝的风险。此外，生态位转移减少了，甚至可以扭转复杂性本来的稳定效应。这种模式的出现是因为具有多个专门化生活阶段的物种在物种水平上似乎是通才，但实际上是按顺序的专家，对资源损失非常敏感。这些结果表明，自然群落比以前的分析所表明的更容易受到生物多样性丧失的影响。
