Data from: Environmental factors influence both abundance and genetic diversity in a widespread bird species

Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations.

遗传多样性（genetic diversity）是与种群大小相关的核心进化变量之一，对种群存活力与物种延续具有至关重要的意义。遗传多样性亦可对种群内部产生重要的生态效应，而生态因子反过来亦可驱动遗传多样性的分布格局。然而迄今为止，关于种群遗传多样性与生态过程间的相互作用关系，仅在少数研究中得到了探索。本研究以常见鸟类家麻雀（Passer domesticus）为研究对象，通过野外调查探究生态因子、局域种群大小与等位基因多样性（allelic diversity）之间的关联。我们于法国南部一处以分散农场和小规模农业为主的封闭小山谷中，在非繁殖季开展了家麻雀调查。对36个采样点的种群普查结果显示，食物可获得性较高的样点内家麻雀种群丰度更高。随后我们从其中12个采样点捕获了891只家麻雀，并对其10个微卫星位点（microsatellite loci）进行了基因分型。种群遗传学分析揭示研究区域内存在微弱的遗传结构，各采样点在研究区域内均形成了独特的亚种群结构。我们发现，在本次检验的诸多因子中，食物可获得性是影响样点间遗传结构的主导因素。上述结果表明，即便在小尺度范围内，生态因子亦可对种群自身大小以及种群内遗传变异产生强烈影响。从更宽泛的层面来看，我们的研究数据表明，生境斑块化与低扩散率可导致遗传多样性呈现精细尺度的分布格局。鉴于遗传多样性对种群存活力的重要性，整合生态与遗传数据有助于识别限制种群规模的关键因子，并明确种群的保护潜力。