Front dynamics in a two-species competition model driven by L¨¦vy flights

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• 作者：Emmanuel Hanert ; ^{emmanuel.hanert@uclouvain.be}
• 关键词：Lotka&ndash ; Volterra model ; Lé ; vy flights ; Anomalous diffusion ; Fractional derivatives ; Front dynamics
• 刊名：Journal of Theoretical Biology
• 出版年：2012
• 出版时间：7 May, 2012
• 年：2012
• 卷：300
• 期：Complete
• 页码：134-142
• 全文大小：498 K

文摘

A number of recent studies suggest that many biological species follow a L¨¦vy random walk in their search for food. Such a strategy has been shown to be more efficient than classical Brownian motion when resources are scarce. However, current diffusion-reaction models used to describe many ecological systems do not account for the superdiffusive spread of populations due to L¨¦vy flights. We have developed a model to simulate the spatial spread of two species competing for the same resources and driven by L¨¦vy flights. The model is based on the Lotka-Volterra equations and has been obtained by replacing the second-order diffusion operator by a fractional-order one. Consistent with previous known results, theoretical developments and numerical simulations show that fractional-order diffusion leads to an exponential acceleration of the population fronts and a power-law decay of the fronts' leading tail. Depending on the skewness of the fractional derivative, we derive catch-up conditions for different types of fronts. Our results indicate that second-order diffusion-reaction models are not well-suited to simulate the spatial spread of biological species that follow a L¨¦vy random walk as they are inclined to underestimate the speed at which these species propagate.