How should dispersal strategies be chosen to increase the likelihood of survival of a species? We obtain the answer for the spatially extended versions of three well-known models of two competing species with unequal diffusivities. Though identical at the mean-field level, the three models exhibit drastically different behavior leading to different optimal strategies for survival, with or without a selective advantage for one species. With conserved total particle number, dispersal has no effect on survival probability. With a fluctuating number, faster dispersal is advantageous if intraspecies competition is present, while moving slower is the optimal strategy for the disadvantaged species if there is no intraspecies competition: it is imperative to include fluctuations to properly formulate survival strategies.

中文翻译：

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固定在竞争人群中：扩散和生存策略

如何选择扩散策略以增加物种生存的可能性？我们获得了两个竞争物种具有不相等扩散率的三个著名模型的空间扩展版本的答案。尽管在平均场水平上相同，但是这三种模型表现出截然不同的行为，导致不同的最优生存策略，对一个物种具有或不具有选择优势。在保留总粒子数的情况下，分散不会影响存活率。随着种群数量的波动，如果存在种内竞争，则较快的分散是有利的；而如果没有种内竞争，则较慢的移动是对处于不利地位的物种的最佳策略：必须包括波动以适当地制定生存策略。