On the evolution of conditional dispersal under environmental and demographic stochasticity
On the evolution of conditional dispersal under environmental and demographic stochasticity
复制标题
环境和人口随机性下条件扩散的演化
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
P. Lundberg
中科院分区：
文献类型：
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作者：
L. A. Bach;Jörgen Ripa;P. Lundberg
问题：在受局部密度调节和环境随机性影响的种群中，密度依赖和代价高昂的扩散将如何演变？什么类型的密度响应将演变，一个强阈值型响应或软响应逐渐增加扩散？方法：一个基于个体的模型，包括密度依赖性，环境波动和人口变化被用来模拟扩散行为的演变。主要假设及变数：个体可以评估栖息地密度之间的瞬时差异，并以此为基础进行扩散行为。然而，未来的密度，从而选择的栖息地补丁未来的质量仍然不确定，由于行为的变化和密度波动。局部密度调节由Beverton-Holt映射给出，受随机环境强迫的影响。个体的扩散决策是斑块密度比的S形函数。允许扩散反应范数的半饱和点和陡度演化。结论：条件扩散从随机行为的状态演变而来，但我们没有观察到阈值扩散作为进化终点（如在以前的模型中发现的）。在一组异质的扩散策略，最成功的反应温和的密度差异，但需要一个大的密度优势，引发移民。虽然阈值扩散可能是进化稳定的，我们建议，这样的终点可能无法实现，如果进化轨迹变得更少的选择和漂移的影响。种群内扩散行为的变异性导致扩散的潜在利益不可预测，因此可能选择保守的移民标准。其他进化的生活史特征，如物候特征，受密度和频率依赖的影响可能会显示出类似的进化模式。（减）
Questions: How will density-dependent and costly dispersal evolve in populations subject to local density regulation and environmental stochasticity? What type of density response will evolve, a strong threshold type response or a soft response gradually increasing dispersal? Method: An individual-based model including density dependence, environmental fluctuations, and population variation was used to simulate evolution of dispersal behaviour. Key assumptions and variables: Individuals can assess the instantaneous difference between habitat densities and base their dispersal behaviour thereon. However, future density and thus future quality of a chosen habitat patch remain uncertain due to behavioural variation and density fluctuations. Local density regulation was given by the Beverton-Holt map, affected by stochastic environmental forcing. An individual’s dispersal decision is a sigmoid function of the density ratio between patch densities. The half-saturation point and steepness of the dispersal reaction norm were allowed to evolve. Conclusions: Conditional dispersal evolves from a state of random behaviour, yet we do not observe threshold dispersal as the evolutionary endpoint (as found in previous models). Among a heterogeneous set of dispersal strategies, the most successful respond softly to density differences but require a large density advantage to trigger emigration. Although threshold dispersal might be evolutionarily stable, we propose that such an endpoint may not be attainable if the evolutionary trajectory becomes less affected by selection and more by drift. The variability in dispersal behaviour within populations leads to unpredictability in the potential benefit of dispersal and hence may select for conservative emigration criteria. Other evolving life-history traits, such as phenological traits, subject to density- and frequency-dependent effects may show similar evolutionary patterns. (Less)
影响因子：
16.8
作者：
Platt TG;Bever JD
通讯作者：
Bever JD