Population-level consequences of risky dispersal

Achieving sufficient connectivity between populations is essential for persistence, but costs of dispersal may select against individual traits or behaviours that, if present, would improve connectivity. Existing dispersal models tend to ignore the multitude of risks to individuals: while many assess the effect of mortality costs, there is also a risk of failing to find new habitat, especially when the entire inhabitable area remains both small and fragmented. There are few known rules governing whether individuals evolve to disperse more, or less, than what is ideal for population connectivity and persistence. Here we aim to fill this gap, while also noting that evolution might not only produce suboptimal dispersal behaviour: it also influences individual heterogeneity in dispersal. Intuitively, we might expect heterogeneity to improve connectivity, as some individuals will travel far. However, we show that this is only true if dispersal distances on average are quite short; heterogene..., readme: instructions for using code and simulation data heremodel simulation data and Matlab code for generating paper figuresfiles_plotcode.zipMatlab code for running model simulationsfiles_runcode.zip

维持种群间足够的连通性是种群存续的关键前提，但扩散行为所带来的成本，可能会对那些本可提升连通性的个体性状或行为产生选择抑制效应。现有扩散模型往往忽略了个体面临的诸多风险：尽管不少模型会评估死亡成本的影响，但个体还存在无法觅得适宜新栖息地的风险，尤其是当整个可栖息区域规模狭小且呈破碎化分布时。目前鲜有已知的法则可用于预判，个体是否会演化出超出或低于种群连通性与存续最优水平的扩散策略。本研究旨在填补这一研究空白，同时需指出：演化过程不仅可能催生次优的扩散行为，还会影响个体在扩散特征上的异质性。从直觉上看，个体扩散的异质性似乎可以提升种群连通性，因为部分个体的扩散距离较远。但本研究表明，仅当平均扩散距离相对较短时，这一推论才成立；扩散异质性……
readme：代码与模拟数据使用说明
用于生成论文配图的模型模拟数据及Matlab代码：files_plotcode.zip
用于运行模型模拟的Matlab代码：files_runcode.zip