Ecology of Biological Invasion - Spatial Spread by Stratified Diffusion

生物入侵生态学 - 分层扩散的空间传播

• 批准号: 06640818
• 负责人: SHIGESADA Nanako
• 金额: $ 1.28万
• 依托单位: Nara Women's University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640818/
• 关键词: stratified diffusion; reaction-diffusion eq.; biological invasion; spread rate; range expansion; cellular automaton; patch dynamics; reaction-diffusion eq.; cellular automaton model

1. When a species colonizes a new area, it spreads across that area in the form of an invasion wave. The speed of this wave is determined by not only by random movement into adjacent areas, but also by long-distance dispersal. We studied the invasion process by using a stratified diffusion model, in which both the short and long range dispersal are taken into account. Expansion rates are calculated from numerical simulations and compared with those previously obtained from the analytical model. The results suggest that the stratified diffusion model should provide a basic framework for exploring the mechanisms underlying range expansion. Applying models to the invasion of the House Finch, we evaluate the effects of long- and short-distance dispersals on the range expansion, separately.2. We investigated the speed of invasion waves in a simple stochastic cellular automaton model for a single species on a homogeneous landscape. We show that stochasticity can dramatically increase the speed of invasion waves compared to a simple deterministic version of the model. To explain this phenomenon mathematically, we developed several approximations to the stochastic model. These showed that the increased wave speed in the stochastic model is due to the irregularity in the shape of the wave front, which is present in the stochastic but not the deterministic model.

1。当一个物种殖民一个新区域时，它以入侵波的形式在该区域散布。该波的速度不仅取决于随机移动到相邻区域，而且还取决于长距离传播。我们通过使用分层扩散模型研究了入侵过程，其中将短距离和远程分散考虑在其中。扩展速率是根据数值模拟计算的，并将其与先前从分析模型获得的膨胀率进行了比较。结果表明，分层扩散模型应为探索范围扩展的机制提供一个基本框架。将模型应用于入侵房屋雀科，我们分别评估了长距离分散对扩展范围扩展的影响。2。我们研究了一个均匀景观上单个物种的简单随机细胞自动机模型中的入侵波速度。我们表明，与模型的简单确定性版本相比，随机性可以大大提高入侵波的速度。为了用数学上的方式解释这一现象，我们开发了几个随机模型的近似值。这些表明，随机模型中的波速增加是由于波前形状的不规则性，这是随机模型中存在的，但不是确定性模型。

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