Dupont L, Torres-Leguizamon M, René-Corail P, Mathieu J
Université Paris Est Créteil (UPEC), Université Pierre et Marie Curie (UPMC), Paris 7, CNRS, INRA, IRD, Institut d'écologie et des Sciences de l'Environnement de Paris, Créteil Cedex, France.
Sorbonne Universités, UPMC, UPEC, Paris 7, CNRS, INRA, IRD, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Paris, France.
Mol Ecol. 2017 Jun;26(12):3128-3140. doi: 10.1111/mec.14102. Epub 2017 Apr 3.
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 (H , A ) 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 F 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.
众所周知，景观特征会改变地上生物的空间遗传变异。在此，我们检验了地下生物的遗传结构也会对景观结构做出响应这一假设。我们利用微卫星标记，在法国北部的一个农业景观区域，对两种内栖蚯蚓物种进行了景观遗传学研究，这两种蚯蚓分别是绿异唇蚓（N = 440，8个微卫星）和黄色正蚓（N = 519，7个微卫星），该区域的景观特征得到了高精度的表征。我们发现，栖息地破碎化在局部尺度上影响了蚯蚓种群的遗传变异。在黄色正蚓种群和绿异唇蚓中，观察到遗传多样性（H、A）与若干景观特征之间存在显著关系。此外，在这两个物种中都观察到不同地点之间存在强烈的遗传分化，遗传混合程度低且F值高。在区域尺度上进行的景观连通性分析，包括距离隔离、最小成本路径和成本加权距离方法，结果表明绿异唇蚓的遗传距离与景观连通性有关。这表明自然栖息地的破碎化塑造了它们的扩散模式和当地有效种群大小。景观连通性分析证实，诸如草地等先验有利栖息地可能构成这些物种的扩散通道。
