Fragmentation of Landscape as a Cause for Genetic Subdivision in Bank Voles

Abstract

We studied the barrier effects of various roadways on the genetic subdivision of bank vole (Clethrionomys glareolus) populations. Allele frequencies, genetic variability, and genetic distances of natural populations were calculated based on polymorphism of seven microsatellite markers. We compared bank vole populations in control areas without such barriers with animals from both sides of a country road, a railway, and a highway. Using F and R statistics, we demonstrated significant population subdivision in bank vole populations separated by the highway, but not in populations on either side of the other roadways or in the control area. Correlations between geographic and genetic distances were revealed by an extended method based on a Mantel analysis. This allowed us to measure genetic barrier effects and express them as additional geographic distances. For instance, statistically significant differences in allele frequencies in all seven loci examined existed among populations in southern Germany and Switzerland, which are separated by the Rhine River and Lake Constance. The real geographic distance between bank vole populations in Konstanz and those in Lengwil, Switzerland, was 6 km. According to this analysis the genetic barrier effect of the Rhine could be defined as an additional distance of 7.7 km. This study shows for the first time that not only old geographic barriers but also more recent fragmentation of landscape by, for example, highways has an important effect on gene flow and the genetic substructuring of populations, which should be considered in future environmental impact assessments.

Gene flow and population structure of a common agricultural wild species (Microtus agrestis) under different land management regimes

“…However, the most important factor in shaping genetic diversity and gene flow was the size of long-standing habitat patches, followed by the accessibility of the sampling site. In agreement with other studies on bank voles (Gerlach and Musolf, 2000), no effect of road presence on the genetic diversity and gene flow was found.…”

The spatial genetic structure of the yellow-necked mouse in an urban environment – a recent invader vs. a closely related permanent inhabitant

“…5). This is undoubtedly a result of the population being divided by an effective natural barrier preventing gene flow, such as a river may pose for small rodents (Aars et al 1998;Gerlach and Musolf 2000;Booth et al 2009;Gortat et al 2015a). The effect is much stronger within the city borders than outside, as is shown by the PCA and STRUCTURE results.…”

Local variation in endoparasite intensities of bank voles (Clethrionomys glareolus) from ecologically similar sites: morphometric and endocrine correlates

“…Exact locations of the sites are given in Behnke et al (2001). The three sites were selected on the basis of their similarity in habitat structure (analysis in Behnke et al, 2001) and their spatial separation (11 -15 km) from each other, well beyond distances known to have resulted in local genetic differentiation of C. glareolus populations (Gerlach & Musolf, 2000). Each site comprised mature mixed woodland of Scots pine (Pinus sylvestris ) and silver birch (Betula verrucosa ), with patches of Norway spruce (Picea abies ), alder (Alnus glutinosa ) and occasional oaks (Quercus robur ).…”