Berthier K, Galan M, Foltête J C, Charbonnel N, Cosson J F
INRA--Centre de Biologie et de Gestion des Populations, Campus International de Baillarguet, CS 30016, 34988 Montferrier sur Lez, France.
Mol Ecol. 2005 Aug;14(9):2861-71. doi: 10.1111/j.1365-294X.2005.02636.x.
Genetic structure can be strongly affected by landscape features and variation through time and space of demographic parameters such as population size and migration rate. The fossorial water vole (Arvicola terrestris) is a cyclic species characterized by large demographic fluctuations over short periods of time. The outbreaks do not occur everywhere at the same time but spread as a wave at a regional scale. This leads to a pattern of large areas (i.e. some hundreds of km2), each with different vole abundances, at any given time. Here, we describe the abundance and genetic structures in populations of the fossorial water vole. We use the data to try to understand how landscape and demographic features act to shape the genetic structure. The spatial variability of vole abundance was assessed from surface indices, collected in spring 2002 (April) in eastern central France. Genetic variability was analysed using eight microsatellite loci at 23 localities sampled between October 2001 and April 2002. We found some congruence between abundance and genetic structures. At a regional scale, the genetic disruptions were associated with both sharp relief and transition between an area of low abundance and another of high abundance. At a local scale, we observed a variation of the isolation-by-distance pattern according to the abundance level of vole populations. From these results we suggest that the dispersal pattern in cyclic rodent populations varies throughout the demographic cycle.
遗传结构会受到景观特征以及诸如种群大小和迁移率等人口统计学参数在时间和空间上变化的强烈影响。穴居水田鼠（Arvicola terrestris）是一种周期性物种，其特征是在短时间内存在巨大的种群数量波动。种群数量的爆发并非在各地同时发生，而是在区域尺度上呈波浪式传播。这导致在任何给定时间出现大面积（即数百平方公里）的格局，每个区域的水田鼠数量都不同。在此，我们描述了穴居水田鼠种群的数量和遗传结构。我们利用这些数据试图了解景观和人口统计学特征如何塑造遗传结构。根据2002年春季（4月）在法国中东部收集的地表指数评估了水田鼠数量的空间变异性。利用2001年10月至2002年4月期间在23个地点采样的8个微卫星位点分析了遗传变异性。我们发现数量和遗传结构之间存在一些一致性。在区域尺度上，遗传中断与地形起伏以及低数量区域和高数量区域之间的过渡有关。在局部尺度上，我们观察到根据水田鼠种群数量水平，距离隔离模式存在变化。从这些结果我们推测，周期性啮齿动物种群的扩散模式在整个种群数量周期中会发生变化。
