Does colonization asymmetry matter in metapopulations?
Does colonization asymmetry matter in metapopulations?
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DOI：
10.1098/rspb.2006.3469
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发表时间：
2006-07
期刊：
影响因子：
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通讯作者：
S. Vuilleumier;H. Possingham
中科院分区：
文献类型：
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作者：
S. Vuilleumier;H. Possingham
尽管有大量证据表明栖息地斑块之间的扩散往往是不对称的，但大多数集合种群模型都假定扩散是对称的。在本文中，我们开发了一个蒙特卡罗模拟模型来量化不对称扩散对集合种群持续性的影响。我们的结果表明，当扩散不对称时，集合种群更有可能灭绝。在具有对称扩散的系统中，集合种群的生存能力与平均场近似结果相符，即如果每个斑块的预期定殖概率超过每个斑块的预期局部灭绝率，系统就会持续存在。对于不对称的情况，平均场近似低估了维持种群持续存在所需的斑块数量。如果在扩散实际上不对称时使用假定对称扩散的模型，在超过50%的情况下对集合种群持续性的估计是错误的。在对称系统中，集合种群的生存能力取决于斑块的连通性，而在不对称的情况下，斑块的数量更为重要。这些结果对于管理可能出现不对称扩散的空间结构种群具有重要意义。未来的集合种群模型应该考虑不对称扩散，同时需要实证研究来量化自然集合种群中不对称扩散的模式及其后果。
Despite the considerable evidence showing that dispersal between habitat patches is often asymmetric, most of the metapopulation models assume symmetric dispersal. In this paper, we develop a Monte Carlo simulation model to quantify the effect of asymmetric dispersal on metapopulation persistence. Our results suggest that metapopulation extinctions are more likely when dispersal is asymmetric. Metapopulation viability in systems with symmetric dispersal mirrors results from a mean field approximation, where the system persists if the expected per patch colonization probability exceeds the expected per patch local extinction rate. For asymmetric cases, the mean field approximation underestimates the number of patches necessary for maintaining population persistence. If we use a model assuming symmetric dispersal when dispersal is actually asymmetric, the estimation of metapopulation persistence is wrong in more than 50% of the cases. Metapopulation viability depends on patch connectivity in symmetric systems, whereas in the asymmetric case the number of patches is more important. These results have important implications for managing spatially structured populations, when asymmetric dispersal may occur. Future metapopulation models should account for asymmetric dispersal, while empirical work is needed to quantify the patterns and the consequences of asymmetric dispersal in natural metapopulations.