Department of Biosciences, University of Helsinki, P.O. Box 65, FI-00014 University of Helsinki, Finland.
Am Nat. 2011 Jan;177(1):29-43. doi: 10.1086/657625. Epub 2010 Nov 19.
We construct a model that combines extinction-colonization dynamics with the dynamics of local adaptation in a network of habitat patches of dissimilar qualities. We derive a deterministic approximation for the stochastic model that allows the calculation of patch-specific incidences of occupancy and levels of adaptation at steady state. Depending on (i) the strength of local selection, (ii) the amount of genetic variance, (iii) the demographic cost of maladaptation, (iv) the spatial scale of gene flow, and (v) the amount of habitat heterogeneity, the model predicts adaptation at different spatial scales. Local adaptation is predicted when there is much genetic variance and strong selection, while network-level adaptation occurs when the demographic cost of maladaptation is low. For little genetic variance and high cost of maladaptation, the model predicts network-level habitat specialization in species with long-range migration but an intermediate scale of adaptation (mosaic specialization) in species with short-range migration. In fragmented landscapes, the evolutionary dynamics of adaptation may both decrease and enhance metapopulation viability in comparison with no evolution. The model can be applied to real patch networks with given sizes, qualities, and spatial positions of habitat patches.
我们构建了一个模型，将灭绝-定居动态与具有不同质量的生境斑块网络中的局部适应动态相结合。我们为随机模型推导出一个确定性近似值，允许在稳定状态下计算斑块特有的占有发生率和适应水平。取决于（i）局部选择的强度，（ii）遗传方差的大小，（iii）适应不良的人口成本，（iv）基因流动的空间尺度，以及（v）生境异质性的大小，该模型预测了不同空间尺度的适应。当存在大量遗传方差和强烈选择时，预测会出现局部适应，而当适应不良的人口成本较低时，会出现网络水平的适应。对于遗传方差较小且适应不良的成本较高的情况，该模型预测具有长距离迁移的物种在网络水平上表现出生境特化，而具有短距离迁移的物种则表现出中间尺度的适应（镶嵌特化）。在破碎的景观中，与没有进化相比，适应的进化动态可能会降低和提高集合种群的生存能力。该模型可以应用于给定大小、质量和生境斑块空间位置的真实斑块网络。
