Evolution of positive and negative density-dependent dispersal
Evolution of positive and negative density-dependent dispersal
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正负密度依赖扩散的演化
DOI：
10.1098/rspb.2014.1226
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
R. Johnstone
中科院分区：
文献类型：
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作者：
António M. M. Rodrigues;R. Johnstone
对于进化生态学家来说，理解依赖密度的扩散策略的进化一直是一个重大挑战。一些现有的模型表明，在扩散过程中，选择应该有利于正的密度依赖，而另一些模型则是负的密度依赖。在这里，我们开发了一个通用模型，该模型展示了选择如何以及为什么会随着关键生态因素，特别是环境的时间稳定性而从正向密度依赖转变为负密度依赖。我们发现，在时间稳定的环境中，特别是在低扩散成本和大种群规模的环境中，栖息地异质性选择负密度依赖的扩散，而在时间可变的环境中，特别是高扩散成本和小种群规模的环境中，栖息地异质性选择正密度依赖的扩散。这种转变反映了在产量更高的地区为繁殖机会而展开的更激烈的竞争与在那里定居的后代更大的长期价值之间不断变化的平衡，后者对环境的暂时稳定性非常敏感。总体而言，个体从低密度斑块扩散出去比从高密度斑块扩散出来对生境异质性更敏感。
Understanding the evolution of density-dependent dispersal strategies has been a major challenge for evolutionary ecologists. Some existing models suggest that selection should favour positive and others negative density-dependence in dispersal. Here, we develop a general model that shows how and why selection may shift from positive to negative density-dependence in response to key ecological factors, in particular the temporal stability of the environment. We find that in temporally stable environments, particularly with low dispersal costs and large group sizes, habitat heterogeneity selects for negative density-dependent dispersal, whereas in temporally variable environments, particularly with high dispersal costs and small group sizes, habitat heterogeneity selects for positive density-dependent dispersal. This shift reflects the changing balance between the greater competition for breeding opportunities in more productive patches, versus the greater long-term value of offspring that establish themselves there, the latter being very sensitive to the temporal stability of the environment. In general, dispersal of individuals out of low-density patches is much more sensitive to habitat heterogeneity than is dispersal out of high-density patches.