Data from: Environmental selection is a main driver of divergence in house sparrows (Passer domesticus) in Romania and Bulgaria

Both neutral and adaptive evolutionary processes can cause population divergence, but their relative contributions remain unclear. We investigated the roles of these processes in population divergence in house sparrows (Passer domesticus) from Romania and Bulgaria, regions characterized by high landscape heterogeneity compared to Western Europe. We asked whether morphological divergence, complemented with genetic data in this human commensal species, was best explained by environmental variation, geographic distance, or landscape resistance—the effort it takes for an individual to disperse from one location to the other—caused by either natural or anthropogenic barriers. Using generalized dissimilarity modeling, a matrix regression technique that fits biotic beta diversity to both environmental predictors and geographic distance, we found that a small set of climate and vegetation variables explained up to ~30% of the observed divergence, whereas geographic and resistance distances played much lesser roles. Our results are consistent with signals of selection on morphological traits and of isolation by adaptation in genetic markers, suggesting that selection by natural environmental conditions shapes population divergence in house sparrows. Our study thus contributes to a growing body of evidence that adaptive evolution may be a major driver of diversification.

中性进化与适应性进化过程均可导致种群分化，但二者的相对贡献仍尚不明确。本研究以罗马尼亚与保加利亚的家麻雀（Passer domesticus）为研究对象，该区域相较于西欧具有更高的景观异质性（landscape heterogeneity），探讨了两类进化过程在其种群分化中的作用。本研究旨在明确：结合该与人伴生物种的遗传数据来看，其形态分化是否可由环境变异、地理距离或景观阻力得到最佳解释——其中景观阻力指个体从一处扩散至另一处所需付出的代价，由自然障碍或人为障碍所导致。本研究采用广义不相似性建模（generalized dissimilarity modeling）——一种将生物β多样性与环境预测因子及地理距离相拟合的矩阵回归方法——进行分析，结果发现，少量气候与植被变量可解释约30%的观测到的种群分化，而地理距离与阻力距离的解释力则相对微弱。我们的结果与形态性状受到选择以及遗传标记呈现适应性隔离的信号相一致，表明自然环境条件的选择作用塑造了家麻雀的种群分化。因此，本研究为日益增多的相关证据链提供了新的支撑，表明适应性进化可能是物种分化的主要驱动力。