Cornell Stephen J, Ovaskainen Otso
Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK.
Theor Popul Biol. 2008 Nov;74(3):209-25. doi: 10.1016/j.tpb.2008.07.003. Epub 2008 Jul 25.
We compute the mean patch occupancy for a stochastic, spatially explicit patch-occupancy metapopulation model on a dynamic, correlated landscape, using a mathematically exact perturbation expansion about a mean-field limit that applies when dispersal range is large. Stochasticity in the metapopulation and landscape dynamics gives negative contributions to patch occupancy, the former being more important at high occupancy and the latter at low occupancy. Positive landscape correlations always benefit the metapopulation, but are only significant when the correlation length is comparable to, or smaller than, the dispersal range. Our analytical results allow us to consider the importance of spatial kernels in all generality. We find that the shape of the landscape correlation function is typically unimportant, and that the variance is overwhelmingly the most important property of the colonisation kernel. However, short-range singularities in either the colonisation kernel or landscape correlations can give rise to qualitatively different behaviour.
我们针对动态、相关景观上的随机、空间明确的斑块占据集合种群模型,使用关于平均场极限的数学精确微扰展开来计算平均斑块占据率,该平均场极限在扩散范围较大时适用。集合种群和景观动态中的随机性对斑块占据率有负贡献,前者在高占据率时更重要,后者在低占据率时更重要。正的景观相关性总是有利于集合种群,但仅当相关长度与扩散范围相当或小于扩散范围时才显著。我们的分析结果使我们能够全面考虑空间核的重要性。我们发现景观相关函数的形状通常并不重要,而定殖核的方差是最重要的属性。然而,定殖核或景观相关性中的短程奇点会导致定性上不同的行为。