Data from: The relative influence of habitat amount and configuration on genetic structure across multiple spatial scales

Despite strong interest in understanding how habitat spatial structure shapes the genetics of populations, the relative importance of habitat amount and configuration for patterns of genetic differentiation remains largely unexplored in empirical systems. In this study, we evaluate the relative influence of, and interactions among, the amount of habitat and aspects of its spatial configuration on genetic differentiation in the pitcher plant midge, Metriocnemus knabi. Larvae of this species are found exclusively within the water-filled leaves of pitcher plants (Sarracenia purpurea) in a system that is naturally patchy at multiple spatial scales (i.e., leaf, plant, cluster, peatland). Using generalized linear mixed models and multimodel inference, we estimated effects of the amount of habitat, patch size, interpatch distance, and patch isolation, measured at different spatial scales, on genetic differentiation (FST) among larval samples from leaves within plants, plants within clusters, and clusters within peatlands. Among leaves and plants, genetic differentiation appears to be driven by female oviposition behaviors and is influenced by habitat isolation at a broad (peatland) scale. Among clusters, gene flow is spatially restricted and aspects of both the amount of habitat and configuration at the focal scale are important, as is their interaction. Our results suggest that both habitat amount and configuration can be important determinants of genetic structure and that their relative influence is scale dependent.尽管学界对阐明生境空间结构如何塑造种群遗传格局抱有浓厚兴趣，但在实证研究体系中，生境总量与空间配置对遗传分化模式的相对重要性仍未得到充分探索。本研究以瓶草摇蚊（Metriocnemus knabi）为研究对象，评估生境总量及其空间配置特征对其遗传分化的相对影响与交互作用。该物种的幼虫仅栖息于紫瓶子草（Sarracenia purpurea）的积水叶筒中，其生存的生态系统在多个空间尺度上呈自然斑块状分布（即叶尺度、植株尺度、簇群尺度及泥炭地尺度）。本研究采用广义线性混合模型（generalized linear mixed models）与多模型推断方法，估算了不同空间尺度下测得的生境总量、斑块面积、斑块间距及斑块隔离度对不同分组幼虫样本间的遗传分化（FST）的影响，分组方式包括植株内的叶间、簇群内的植株间及泥炭地内的簇群间。在叶间与植株间层面，遗传分化主要受雌性成虫产卵行为驱动，并受大尺度（泥炭地尺度）的生境隔离影响。在簇群层面，基因流存在空间限制，局地尺度的生境总量与配置特征及其交互作用均对遗传分化具有重要影响。本研究结果表明，生境总量与空间配置均可作为种群遗传结构的重要决定因素，且二者的相对影响具有尺度依赖性。