Wu Hong, Wang Yuanshi, Li Yufeng, DeAngelis Donald L
School of Mathematics, Sun Yat-sen University, Guangzhou 510275, PR China.
School of Mathematics, Sun Yat-sen University, Guangzhou 510275, PR China.
Theor Popul Biol. 2020 Feb;131:54-65. doi: 10.1016/j.tpb.2019.11.004. Epub 2019 Nov 25.
This paper analyzes source-sink systems with asymmetric dispersal between two patches. Complete analysis on the models demonstrates a mechanism by which the dispersal asymmetry can lead to either an increased total size of the species population in two patches, a decreased total size with persistence in the patches, or even extinction in both patches. For a large growth rate of the species in the source and a fixed dispersal intensity, (i) if the asymmetry is small, the population would persist in both patches and reach a density higher than that without dispersal, in which the population approaches its maximal density at an appropriate asymmetry; (ii) if the asymmetry is intermediate, the population persists in both patches but reaches a density less than that without dispersal; (iii) if the asymmetry is large, the population goes to extinction in both patches; (iv) asymmetric dispersal is more favorable than symmetric dispersal under certain conditions. For a fixed asymmetry, similar phenomena occur when the dispersal intensity varies, while a thorough analysis is given for the low growth rate of the species in the source. Implications for populations in heterogeneous landscapes are discussed, and numerical simulations confirm and extend our results.
本文分析了两个斑块之间具有不对称扩散的源 - 汇系统。对模型的完整分析揭示了一种机制，通过该机制扩散不对称性可能导致两个斑块中物种种群的总规模增加、斑块中总规模减小但仍持续存在，甚至两个斑块中的物种都灭绝。对于源斑块中物种的高增长率和固定的扩散强度，（i）如果不对称性较小，种群将在两个斑块中持续存在并达到比无扩散时更高的密度，在适当的不对称性下种群接近其最大密度；（ii）如果不对称性中等，种群在两个斑块中持续存在，但达到的密度低于无扩散时；（iii）如果不对称性较大，种群在两个斑块中都会灭绝；（iv）在某些条件下，不对称扩散比对称扩散更有利。对于固定的不对称性，当扩散强度变化时会出现类似现象，同时对源斑块中物种的低增长率进行了全面分析。讨论了对异质景观中种群的影响，数值模拟证实并扩展了我们的结果。
