Genetic structure of the cyclic fossorial water vole (Arvicola terrestris): landscape and demographic influences

Abstract

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.

Connectivity rescues genetic diversity after a demographic bottleneck in a butterfly population network

“…The low power of single sampling-period bottleneck detection methods has been previously noted (18,19), and in our study system, the effectiveness of such methods may be particularly limited by the occurrence of immigration, which can erase a genetic bottleneck signature in two to three generations (20,21).…”

Landscape structure and the genetic effects of a population collapse

“…Connectivity among populations, in turn, is strongly influenced by landscape characteristics [11][12][13]. Conversely, landscape composition and configuration can influence background levels of genetic drift and gene flow, resulting in associations between landscape variables and patterns of genetic diversity or spatial genetic structure [2,14]. Within a network of populations, severe reductions in local or regional population size would lead to greater genetic differentiation, essentially as a result of increased genetic drift [1,15].…”

Host habitat patchiness and the distance decay of similarity among gastro-intestinal nematode communities in two species of Mastomys (southeastern Senegal)

“…First, habitat fragmentation could limit dispersion so that host movements would be too rare to favour parasite exchange between population pairs. Making an analogy with the process of isolation by distance used by population geneticists, absence of distance decay may be related to very low host dispersal levels, because absence of genetic isolation by distance can occur in gene Xow ruptures between populations (Berthier et al 2005). DiVerences between parasite communities would be mainly explained by stochastic events (Fellis and Esch 2005).…”