Data from: Landscape features impact connectivity between soil populations: a comparative study of gene flow in earthworms

Landscape features are known to alter the spatial genetic variation of aboveground organisms. Here, we tested the hypothesis that the genetic structure of belowground organisms also responds to landscape structure. Microsatellite markers were used to carry out a landscape genetic study of two endogeic earthworm species, Allolobophora chlorotica (N = 440, eight microsatellites) and Aporrectodea icterica (N = 519, seven microsatellites), in an agricultural landscape in the North of France, where landscape features were characterized with high accuracy. We found that habitat fragmentation impacted genetic variation of earthworm populations at the local scale. A significant relationship was observed between genetic diversity (He, Ar) and several landscape features in A. icterica populations and A. chlorotica. Moreover, a strong genetic differentiation between sites was observed in both species, with a low degree of genetic admixture and high Fst values. The landscape connectivity analysis at the regional scale, including isolation by distance, least-cost path and cost-weighted distance approaches, showed that genetic distances were linked to landscape connectivity in A. chlorotica. This indicates that the fragmentation of natural habitats has shaped their dispersal patterns and local effective population sizes. Landscape connectivity analysis confirmed that a priori favourable habitats such as grasslands may constitute dispersal corridors for these species.景观特征可改变地表生物的空间遗传变异，这一点已得到学界共识。本研究针对地下生物的遗传结构同样响应景观结构这一假说展开验证。我们使用微卫星标记（microsatellite markers），对法国北部某农业景观中的两种内生蚯蚓物种——绿带异唇蚓（Allolobophora chlorotica，N=440，采用8个微卫星位点）与黄色前蚓（Aporrectodea icterica，N=519，采用7个微卫星位点）开展景观遗传学研究，该研究区域的景观特征已被高精度表征。研究发现，生境破碎化在局域尺度上对蚯蚓种群的遗传变异产生了显著影响。我们观察到，两种蚯蚓种群的遗传多样性（期望杂合度He、等位基因丰富度Ar）与多项景观特征均存在显著关联。此外，两个物种的种群间均呈现出强烈的遗传分化，表现为较低的遗传混合度与较高的Fst值（遗传固定指数，Fixation Index）。在区域尺度开展的景观连通性分析（涵盖隔离距离、最小成本路径与成本加权距离三种分析方法）结果显示，绿带异唇蚓的遗传距离与景观连通性显著相关。这表明自然生境的破碎化塑造了它们的扩散模式与局域有效种群规模。景观连通性分析进一步证实，草地等先验认定的适宜生境可作为这些物种的扩散廊道。