Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL 32308, U.S.A.
Department of Environmental Science and Policy, University of California, One Shields Ave, Davis, CA 95616, U.S.A.
Biol Rev Camb Philos Soc. 2016 Aug;91(3):867-82. doi: 10.1111/brv.12198. Epub 2015 Jun 26.
Recent syntheses on the evolutionary causes of dispersal have focused on dispersal as a direct adaptation, but many traits that influence dispersal have other functions, raising the question: when is dispersal 'for' dispersal? We review and critically evaluate the ecological causes of selection on traits that give rise to dispersal in marine and terrestrial organisms. In the sea, passive dispersal is relatively easy and specific morphological, behavioural, and physiological adaptations for dispersal are rare. Instead, there may often be selection to limit dispersal. On land, dispersal is relatively difficult without specific adaptations, which are relatively common. Although selection for dispersal is expected in both systems and traits leading to dispersal are often linked to fitness, systems may differ in the extent to which dispersal in nature arises from direct selection for dispersal or as a by-product of selection on traits with other functions. Our analysis highlights incompleteness of theories that assume a simple and direct relationship between dispersal and fitness, not just insofar as they ignore a vast array of taxa in the marine realm, but also because they may be missing critically important effects of traits influencing dispersal in all realms.
最近关于扩散进化原因的综合研究集中在扩散作为一种直接适应上，但许多影响扩散的特征具有其他功能，这就提出了一个问题：什么时候扩散是为了扩散？我们回顾并批判性地评估了导致海洋和陆地生物扩散的特征的生态选择原因。在海洋中，被动扩散相对容易，而特定的形态、行为和生理适应扩散的特征却很少见。相反，可能经常会有选择来限制扩散。在陆地上，没有特定的适应，扩散就相对困难，而这些适应相对常见。尽管在这两个系统中都期望有扩散的选择，并且导致扩散的特征通常与适应性相关，但在自然界中，扩散是直接选择扩散的结果还是选择具有其他功能的特征的副产品，系统可能存在差异。我们的分析强调了那些假设扩散和适应性之间存在简单直接关系的理论的不完整性，不仅因为它们忽略了海洋领域中大量的分类群，还因为它们可能错过了所有领域中影响扩散的特征的重要影响。
