Patchy populations in stochastic environments: Critical number of patches for persistence
Patchy populations in stochastic environments: Critical number of patches for persistence
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DOI：
10.1086/324793
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发表时间：
2002-02-01
影响因子：
2.9
通讯作者：
Roughgarden, J
中科院分区：
文献类型：
--
作者：
Bascompte, J;Possingham, HP;Roughgarden, J
我们介绍了一个模型的动态斑块人口在随机环境中，并推导出一个准则，其持久性。这一标准的依据是增长率空间算术平均值的时间几何平均值。要使种群持续存在，GM必须大于或等于1。GM随着斑块数量的增加而增加（因为抽样误差减少），并随着增长率的方差和空间协方差而减少。我们推导出解析表达式的最小数量的补丁（和最大收获率）所需的持久性的人口。随着环境波动幅度的增加，持续性所需的斑块数量增加，可以收获的个体比例减少。我们的方法的新奇在于，我们专注于马尔萨斯当地的人口动态与高分散性和强的环境变化，从一年到一年。与以往的模型，假设一个无限数量的补丁人口，我们专注于具体的补丁数量对人口持久性的影响。因此，我们的工作是直接相关的斑块分布的生物，仅限于少数栖息地补丁。
We introduce a model for the dynamics of a patchy population in a stochastic environment and derive a criterion for its persistence. This criterion is based on the geometric mean (GM) through time of the spatial-arithmetic mean of growth rates. For the population to persist, the GM has to be greater than or equal to1. The GM increases with the number of patches (because the sampling error is reduced) and decreases with both the variance and the spatial covariance of growth rates. We derive analytical expressions for the minimum number of patches (and the maximum harvesting rate) required for the persistence of the population. As the magnitude of environmental fluctuations increases, the number of patches required for persistence increases, and the fraction of individuals that can be harvested decreases. The novelty of our approach is that we focus on Malthusian local population dynamics with high dispersal and strong environmental variability from year to year. Unlike previous models of patchy populations that assume an infinite number of patches, we focus specifically on the effect that the number of patches has on population persistence. Our work is therefore directly relevant to patchily distributed organisms that are restricted to a small number of habitat patches.