Genetic structure of regional water vole populations and footprints of reintroductions: a case study from southeast England

Abstract

An important consideration when implementing species management is preserving genetic variation, which is fundamental to the long-term persistence of populations and adaptive potential of the species. The European water vole Arvicola amphibius is of high conservation importance in the United Kingdom due to its documented decline in both distribution and abundance. Conservation strategies for this species include protecting source populations, increasing habitat availability and connectivity, non-native predator control and reintroduction. We used mtDNA control region sequences and eight microsatellite markers from samples collected from 12 localities in southeast England, to determine how genetic variation is structured amongst regional water vole populations and to what extent population structure has been influenced by reintroductions. We found high haplotype diversity (h) across native populations in the southeast region and evidence that divergent lineages had been introduced to the region. We detected significant structure between watersheds with mtDNA from native populations and evidence of finer scale structure between populations within watersheds with both mtDNA and microsatellites. We suggest that management strategies should aim to conserve genetic diversity at a population level and that watersheds are a practicable unit for prioritising management within regions. We propose that introductions to restore or augment water voles within watersheds should consider the genetic composition of regional populations and highlight that genetic data has an important role in guiding future conservation options that secure adaptive potential in the face of future environmental change.

Mitochondrial Genome Evolution, Genetic Diversity, and Population Structure in British Water Voles (Arvicola amphibius)

“…The maintenance of these two British lineages is necessary due to their considerable divergence and their distinct evolutionary history. In the Southeast of England, water vole mtDNA was found to be structured by watershed and it was suggested that conservation management should take place at a local level to maintain local genetic heritage [ 13 ]. Ex-situ conservation can be a useful tool to halt the decline of species, especially when genetics and pedigrees are considered.…”

“…In the Southeast and East of England populations of natural water voles showed considerable haplotype diversity and substantial genetic structure between watershed populations, and finer-scale structure between populations within watersheds, when using the mitochondrial DNA control region and microsatellite markers of natural populations [ 13 , 14 ]. However, a detailed study on captive populations of water voles is missing, hindering the outcomes of current conservation efforts.…”