Data from: The structural and functional connectivity of the grassland plant Lychnis flos-cuculi

Understanding the relationship between structural and functional connectivity is essential for successful restoration and conservation management, particularly in intensely managed agricultural landscapes. We evaluated the relationship between structural and functional connectivity of the wetland plant Lychnis flos-cuculi in a fragmented agricultural landscape using landscape genetic and network approaches. First, we studied the effect of structural connectivity, such as geographic distance and various landscape elements (forest, agricultural land, settlements and ditch verges), on gene flow among populations as a measurement of functional connectivity. Second, we examined the effect of structural graph-theoretic connectivity measures on gene flow among populations and on genetic diversity within populations of L. flos-cuculi. Among landscape elements, forests hindered gene flow in L. flos-cuculi, whereas gene flow was independent of geographic distance. Among the structural graph-theoretic connectivity variables, only intrapopulation connectivity, which was based on population size, had a significant positive effect on gene flow, that is, more gene flow took place among larger populations. Unexpectedly, interpopulation connectivity of populations, which takes into account the spatial location and distance among populations, did not influence gene flow in L. flos-cuculi. However, higher observed heterozygosity and lower inbreeding was observed in populations characterised by higher structural interpopulation connectivity. This finding shows that a spatially coherent network of populations is significant for maintaining the genetic diversity of populations. Nevertheless, lack of significant relationships between gene flow and most of the structural connectivity measures suggests that structural connectivity does not necessarily correspond to functional connectivity.

解析结构连通性（structural connectivity）与功能连通性（functional connectivity）之间的关联，对于成功开展生境修复与保护管理至关重要，在高强度经营的农业景观中尤为关键。本研究以破碎化农业景观中的湿地植物剪秋罗（Lychnis flos-cuculi）为研究对象，采用景观遗传学与网络分析方法，评估二者之间的关系。其一，我们以种群间基因流（gene flow）作为功能连通性的衡量指标，探究了地理距离、森林、农田、居民点与沟渠边缘等多种景观要素构成的结构连通性对基因流的影响。其二，我们分析了基于图论的结构连通性指标对剪秋罗种群间基因流以及种群内遗传多样性（genetic diversity）的影响。在各类景观要素中，森林会阻碍剪秋罗的种群间基因流，而基因流与地理距离并无关联。在基于图论的结构连通性变量中，仅以种群规模为基础的种群内连通性（intrapopulation connectivity）对基因流存在显著正向影响，即种群规模越大，种群间的基因交流越频繁。出乎意料的是，考虑种群空间位置与种群间距离的种群间连通性（interpopulation connectivity）并未对剪秋罗的基因流产生显著影响。但在结构上种群间连通性更高的种群中，观测到的杂合度（observed heterozygosity）更高，近交（inbreeding）程度更低。该结果表明，空间结构连贯的种群网络对维持种群遗传多样性具有重要意义。尽管如此，基因流与多数结构连通性指标之间未呈现显著关联，这说明结构连通性未必能够反映功能连通性。