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.

尽管学界对解析生境空间结构如何塑造种群遗传特征抱有浓厚兴趣，但在实际观测系统中，生境总量与空间配置对遗传分化格局的相对重要性仍未得到充分探索。本研究以瓶子草摇蚊（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，该研究系统在多个空间尺度（即叶筒、植株、簇群、泥炭地）上均呈现自然斑块分布特征。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、斑块间距与斑块隔离度等因子对不同分组（叶筒内植株间、簇群内植株间、泥炭地内簇群间）幼虫样本间的遗传分化（FST）的影响。在叶筒与植株层级，遗传分化主要由雌虫产卵行为调控，同时受到大尺度（泥炭地尺度）生境隔离的影响。在簇群层级，基因流存在空间限制，局域尺度下的生境总量、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能是种群遗传结构的重要决定因素，且二者的相对影响程度依赖于空间尺度。