Genetic Structure of the Root Vole Microtus oeconomus: Resistance of the Habitat Specialist to the Natural Fragmentation of Preferred Moist Habitats

Abstract

Climate-related changes have a severe impact on wetland ecosystems and pose a serious challenge for wetland-dependent animals as their preferred habitats decline, lose spatial continuity, and appear as isolated islands in the landscape. In this paper, we studied the effects of long-term habitat changes (drying out and fragmentation of wet non-forest habitats) on the genetic structure of the population of the root vole Microtus oeconomus, a species preferring moist habitats. We intended to check what barriers and what distances affected its genetic isolation on a local scale. The study was conducted in the area of Kampinoski National Park in central Poland (Europe). DNA variability of 218 root vole individuals was assessed by genotyping nine microsatellite loci. Despite its spatial fragmentation, the studied population did not seem to be highly structured, and isolation through distance was the main differentiating factor. Even a distance of several kilometres of unfavourable natural habitats and unfavourable terrain did not exclude the exchange of genes between subpopulations. Our results suggest that the genetic effects of the fragmentation of wetlands have been considerably compensated (delayed) due to the migratory abilities of this species. Our study does not provide clear results on the impact of anthropogenic barriers but suggests that such barriers may have a much stronger effect than natural barriers.

Low Genetic Variability of the Tundra Vole in Lithuania

“…Genetic isolation also operates at a local scale [15], accentuating the impacts of climatechange-related alterations to wetland ecosystems and the desiccation of wet grasslands. Lopucki et al demonstrated that gene exchange between local populations of A. oeconomus is possible even when separated by several kilometers of unfavorable habitat, but anthropogenic barriers may exert a stronger isolating effect [10]. Population fragmentation is also prevalent in other countries, such as Hungary [18] and Austria [62].…”

“…In our study, the two northern sites are situated in an anthropogenized landscape characterized by intensive agriculture and fragmented wet habitats. The dispersal potential of A. oeconomus may not be sufficient to counteract the genetic effects of isolation [10,57].…”

“…The most widespread species is the tundra vole (Alexandromys oeconomus (Pallas, 1776)). However, not all investigations recognize the validity of the subgenus Alexandromys [7], so this species is also recognized as Microtus oeconomus (Pallas, 1776) [9][10][11]. Here, we use A. oeconomus, following the nomenclature proposed by the American Society of Mammalogists and IUCN [12,13].…”

“…Long-term habitat changes in the Kis Balaton area in Hungary have resulted in the isolation and low genetic variability of A. oeconomus, which differs from other Hungarian, Austrian, and Slovak populations [18]. However, data on the genetic structure of A. oeconomus in Poland were different [10]. The Polish authors found that isolation due to distance is a major factor in genetic differentiation.…”

“…The Polish authors found that isolation due to distance is a major factor in genetic differentiation. While natural barriers can be overcome due to the migratory capacity of the species, anthropogenic barriers can have a much stronger effect [10].…”