Data from: Differential effects of landscape-level environmental features on genetic structure in three co-distributed tree species in Central America

Landscape genetic studies use spatially explicit population genetic information to determine the physical and environmental causes of population genetic structure on regional scales. Comparative studies that identify common barriers to gene flow across multiple species within a community are important to both understand the evolutionary trajectories of populations and to prioritize habitat conservation. Here, we use a comparative landscape genetic approach to ask whether gradients in temperature or precipitation seasonality structure genetic variation across three co-distributed tree species in Central America, or if a simpler (geographic distance) or more complex, species-specific environmental niche model is necessary to individually explain population genetic structure. Using descriptive statistics and causal modeling, we find that different environmental factors best explain genetic distance in each of the three species: environmental niche distance in Bursera simaruba, geographic distance in Ficus insipida, while either historical contingency or cryptic reproductive barriers influence predictions for Brosimum alicastrum. This study confirms suggestions from previous studies of Central American tree species that imply that population genetic structure of trees in this region is determined by complex interactions of both historical and current barriers to gene flow.

景观遗传学研究（Landscape genetic studies）借助空间显性种群遗传信息，以解析区域尺度下种群遗传结构形成的物理与环境诱因。针对群落内多个物种类群间共有的基因流障碍开展的比较研究，对于阐明种群演化轨迹与确定栖息地保护的优先次序均具备重要价值。本研究采用比较景观遗传学方法，旨在探究中美洲3个同分布树种的遗传变异是否受温度或降水季节性梯度调控，亦或是仅需地理距离这一简单变量，抑或是需要更复杂的物种专属生态位模型来分别解释其种群遗传结构。本研究通过描述性统计与因果建模分析发现，3个树种的遗传距离分别由不同的环境因素最优解释：Bursera simaruba的遗传距离由生态位距离最优解释，Ficus insipida的遗传距离由地理距离主导，而Brosimum alicastrum的种群遗传结构预测则受历史偶然性或隐蔽生殖障碍的影响。本研究验证了此前中美洲树种相关研究的推论——该区域树木的种群遗传结构由基因流的历史障碍与当代障碍通过复杂交互作用共同塑造。