Food web complexity and stability across habitat connectivity gradients
Food web complexity and stability across habitat connectivity gradients
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栖息地连通梯度的食物网复杂性和稳定性
作者：
Robin M. LeCraw;P. Kratina;D. Srivastava
栖息地的连通性对食物网的影响已被研究的经验和理论，但问题的实证结果是否支持理论预测的任何食物网度量比物种丰富度得到了很少的关注。我们的综合汇集了理论和经验证据，栖息地的连通性如何影响食物网的稳定性和复杂性。食物网的稳定性往往被预测为最大的中间水平的连接，通过救援效果和猎物切换扩散的稳定效果之间的妥协，和通过区域同步的人口动态扩散的不稳定影响。对食物网稳定性的实证研究普遍支持这一模式和潜在机制。食物链长度已被预测有增加和单峰的关系，连接作为一个结果的捕食者被限制的补丁占用他们的猎物。虽然这两种模式都有经验证明，但其潜在机制可能与模型预测的机制不同。在其他措施的食物网的复杂性，栖息地的连通性已被经验发现，一般增加链接密度，但要么减少或没有影响连接，而单峰关系的预期。在一般情况下，有越来越多的一致性之间的经验模式和理论预测的一些影响栖息地的连接食物网，但许多预测仍有待测试，在一个完整的连接梯度，经验指标的复杂性很少建模。缩小这些差距将使人们更深入地了解自然和人为的连通性变化如何影响真实的食物网。
The effects of habitat connectivity on food webs have been studied both empirically and theoretically, yet the question of whether empirical results support theoretical predictions for any food web metric other than species richness has received little attention. Our synthesis brings together theory and empirical evidence for how habitat connectivity affects both food web stability and complexity. Food web stability is often predicted to be greatest at intermediate levels of connectivity, representing a compromise between the stabilizing effects of dispersal via rescue effects and prey switching, and the destabilizing effects of dispersal via regional synchronization of population dynamics. Empirical studies of food web stability generally support both this pattern and underlying mechanisms. Food chain length has been predicted to have both increasing and unimodal relationships with connectivity as a result of predators being constrained by the patch occupancy of their prey. Although both patterns have been documented empirically, the underlying mechanisms may differ from those predicted by models. In terms of other measures of food web complexity, habitat connectivity has been empirically found to generally increase link density but either reduce or have no effect on connectance, whereas a unimodal relationship is expected. In general, there is growing concordance between empirical patterns and theoretical predictions for some effects of habitat connectivity on food webs, but many predictions remain to be tested over a full connectivity gradient, and empirical metrics of complexity are rarely modeled. Closing these gaps will allow a deeper understanding of how natural and anthropogenic changes in connectivity can affect real food webs.