Accelerating invasion rates result from the evolution of density-dependent dispersal
Accelerating invasion rates result from the evolution of density-dependent dispersal
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DOI：
10.1016/j.jtbi.2009.03.008
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发表时间：
2009-07-07
影响因子：
2
通讯作者：
Dytham, Calvin
中科院分区：
文献类型：
--
作者：
Travis, Justin M. J.;Mustin, Karen;Dytham, Calvin
进化过程在形成范围扩张的动力学方面起着重要作用，对扩散倾向的选择已被证明可以加速前进的速度。以前的理论只考虑了无条件扩散率的演化，但扩散往往更为复杂。例如，许多物种因拥挤而迁移。在这里，我们使用一个基于个人的模型来研究密度依赖扩散到空的栖息地，如在入侵的演变。景观被表示为一个网格和人口之间的扩散遵循一个踏脚石模式。个体携带三个“基因”，决定了它们在经历不同的种群密度时的扩散策略。对于一个固定的范围内，我们得到的结果与以前的理论研究一致：很少有人移民的补丁，低于平衡密度。然而，在以前的固定人口的范围扩大，我们观察到相当大的移民发生远低于平衡密度的扩散策略的演变。这是真实的，即使是适度的成本分散，并始终导致范围扩大的速度加快。重要的是，我们在一个不断扩大的前沿观察到的进化取决于几代人的适应性，不能仅仅通过考虑一生的生殖成功来预测。我们认为，更好地了解密度依赖扩散的作用，及其演变，在驱动人口动态的范围内扩展的背景下，特别是需要。(C)2009爱思唯尔有限公司保留所有权利。
Evolutionary processes play an important role in shaping the dynamics of range expansions, and selection on dispersal propensity has been demonstrated to accelerate rates of advance. Previous theory has considered only the evolution of unconditional dispersal rates, but dispersal is often more complex. For example, many species emigrate in response to crowding. Here, we use an individual-based model to investigate the evolution of density dependent dispersal into empty habitat, such as during an invasion. The landscape is represented as a lattice and dispersal between Populations follows a stepping-stone pattern. Individuals carry three 'genes' that determine their dispersal strategy when experiencing different population densities. For a stationary range we obtain results consistent with previous theoretical studies: few individuals emigrate from patches that are below equilibrium density. However, during the range expansion of a previously stationary population, we observe evolution towards dispersal strategies where considerable emigration occurs well below equilibrium density. This is true even for moderate costs to dispersal, and always results in accelerating rates of range expansion. Importantly, the evolution we observe at an expanding front depends upon fitness integrated over several generations and cannot be predicted by a consideration of lifetime reproductive success alone. We argue that a better understanding of the role of density dependent dispersal, and its evolution, in driving population dynamics is required especially within the context of range expansions. (C) 2009 Elsevier Ltd. All rights reserved.