Data from: Effects of conditionally expressed phenotypes and environment on amphibian dispersal in nature

Individuals vary greatly in the distance they disperse, and in doing so, strongly affect ecological and evolutionary processes. Dispersal, when viewed as a component of phenotype, can be affected independently or jointly by environment. However, among taxa with complex life cycles that occupy different habitats over ontogeny, the effects of environment on dispersal and the interaction between environment and phenotype remains poorly understood. Here, we conducted a field experiment to measure how dispersal distance was affected by phenotype, environment experienced before and after metamorphosis, and their interaction. We manipulated the environment encountered by a pond-breeding salamander (Ambystoma annulatum) during the aquatic larval stage and again as dispersing terrestrial juveniles. After assaying juvenile phenotype (exploration behavior, body condition, and morphology), we then measured the initial distance dispersed by juveniles. The distance moved by dispersing salamanders was affected by attributes of both larval and juvenile habitat, with salamanders that encountered low quality habitat in either life stage moving the farthest. However, we did not find support for an interactive effect of phenotype and environment affecting the distance moved by dispersers. Interestingly, exploration behavior explained the distance moved by philopatric animals but not dispersing ones. Our findings indicate that the environment experienced before metamorphosis can affect juvenile dispersal behavior, and demonstrates the need to consider dispersal in species with complex life cycles to understand the coupling between local and regional population dynamics.

个体在扩散距离上存在显著差异，而这一差异会强烈影响生态与进化过程。扩散若被视为表型（phenotype）的组成部分，则可受环境独立或联合调控。然而，对于在个体发育过程中占据不同生境的复杂生活史类群而言，环境对扩散的影响以及环境与表型间的互作机制仍不甚明晰。本研究通过野外实验，探究了表型、变态前后所经历的环境及其交互作用对扩散距离的影响。我们针对一种繁殖于池塘的环纹钝口螈（Ambystoma annulatum），分别调控其水生幼体阶段以及陆生扩散稚体阶段所遭遇的环境条件。在测定幼体表型（探索行为、身体状况与形态特征）后，我们进一步测量了稚体的初始扩散距离。扩散蝾螈的移动距离受水生幼体与陆生稚体生境的属性共同调控，且无论在哪个生活史阶段遭遇低质量生境的个体，其移动距离均最远。但本研究未发现表型与环境的交互作用对扩散者移动距离存在显著影响的证据。值得注意的是，探索行为可解释留居个体的移动距离，但无法解释扩散个体的移动距离。本研究结果表明，变态前经历的环境可影响幼体扩散行为，同时也证实，若要理解局域与区域种群动态间的耦合关系，需将扩散因素纳入复杂生活史物种的研究框架中。