Kinezaki Noriko, Kawasaki Kohkichi, Shigesada Nanako
Faculty of Informatics, Nara Sangyo University, Sango-cho, Ikoma-gun, Nara 636-8503, Japan.
Theor Popul Biol. 2010 Dec;78(4):298-308. doi: 10.1016/j.tpb.2010.09.002. Epub 2010 Sep 25.
To address how the spatial configuration of habitat fragmentation influences the persistence and the rate of spread of an invasive species, we consider three simple periodically fragmented environments, a lattice-like corridor environment, an island-like environment and a striped environment. By numerically analyzing Fisher's equation with a spatially varying diffusion coefficient and the intrinsic growth rate, we find the following. (1) When the scale of fragmentation is sufficiently large, the minimum favorable area needed for successful invasion reduces in the following order: lattice-like corridor, striped and island-like environments. (2) When the scale of fragmentation and the fraction of favorable area are sufficiently large, the spreading speeds along contiguous favorable habitats in the lattice-like corridor and striped environments are faster than the speeds across isolated favorable habitats in the island-like environment and the striped environment. (3) When the periodicity of fragmentation is relaxed by stochastically shifting the boundaries between favorable and unfavorable habitats, the average speed increases with increases in the irregularity of fragmentation.
为了探讨栖息地破碎化的空间配置如何影响入侵物种的持久性和扩散速度，我们考虑了三种简单的周期性破碎化环境，一种类似格子状的廊道环境、一种类似岛屿的环境和一种条纹状环境。通过对具有空间变化扩散系数和内在增长率的费希尔方程进行数值分析，我们得到以下结果。（1）当破碎化规模足够大时，成功入侵所需的最小适宜面积按以下顺序减小：类似格子状的廊道、条纹状和类似岛屿的环境。（2）当破碎化规模和适宜面积比例足够大时，在类似格子状的廊道和条纹状环境中沿着连续适宜栖息地的扩散速度比在类似岛屿的环境和条纹状环境中跨越孤立适宜栖息地的速度更快。（3）当通过随机移动适宜和不适宜栖息地之间的边界来放宽破碎化的周期性时，平均速度随着破碎化不规则性的增加而增加。
