Using population genetics and scent deposits to inform recovery strategies for a threatened UK mammal

Water voles (Arvicola amphibius) are the largest of Britain's three native vole species, and one of the UK's fastest declining mammals, with a dramatic 30% decline in just 10 years (2006-2015). Population fragmentation erodes genetic variability and increases inbreeding, which further threaten long term population persistence. As a priority conservation species, it is vital to understand genetic status and distinctiveness of local water vole populations, allowing implementation of appropriate and robust recovery strategies.

This project, working alongside Cheshire Wildlife Trust will; a) Assess genetic variability and degree of inbreeding within remnant water vole populations in Cheshire b) Test the negative impact of relatedness and inbreeding on reproductive maturation, survival and productivity, while also taking vole social and sexual responses into account, and c) Establish the genetic distinctiveness of Cheshire water voles compared to other regions around the UK.

Gaining this information from fragile populations presents a substantial challenge, requiring a range of non-invasive approaches (utilising faeces and scent deposits) to minimise disturbance and allow reliable replication for UK conservation organisations.

Background
Water voles (Arvicola amphibius) are the largest of Britain's three native vole species. Although once common, they have disappeared from 94% of their former sites across the UK. One of the UK's fastest declining mammals, with a dramatic 30% decline in just 10 years (2006-2015), they are a priority conservation species. Habitat loss and predation by invasive American mink are the major causes, requiring urgent conservation efforts to both stop the decline and help populations recover.

Increasing population fragmentation erodes genetic variability, leading to inbreeding within small remnant populations. Reintroductions, population augmentation and improved habitat connectivity within and between populations are potential strategies to aid recovery. However, understanding genetic status and distinctiveness of local populations is essential to design appropriate recovery strategies, while also taking vole social and sexual responses into account. Gaining information from fragile populations presents a substantial challenge, requiring the development of non-invasive approaches that minimise disturbance. Faeces and other deposits that voles use for communication provide an excellent opportunity to gain genotypic and phenotypic information that, so far, has been little explored.

Objectives
This project will focus primarily on water voles in Cheshire, where reliable survey data are available from the past 20 years.
Key aims:
1) Assess genetic variability and degree of inbreeding within remnant populations.
2) Test the negative impact of relatedness and inbreeding on reproductive maturation, survival and productivity.
3) Establish the genetic distinctiveness of Cheshire water voles compared to other regions around the UK.
4) Develop techniques to reliably recover genotypic and phenotypic information non-invasively from faeces and other vole deposits.

Novelty & Timeliness
There is an urgent need for active conservation of water voles across the UK, informed by strong scientific data. Combining field studies with cutting edge molecular approaches aims to substantially improve the level of information available to guide conservation planning, and will feed directly into Cheshire Wildlife Trust's water vole recovery plan.