Distribution, range and ecological impacts of non-native small mammals

This 3-year PhD will assess the distribution, range, abundance and ecological impacts of non-native small mammals in Northern Ireland focusing on the bank vole, field vole and potentially greater white-toothed shrew.

Ireland has a biogeographically unique community of flora and fauna shaped by its geological and human history. Like most islands it is also highly vulnerable to invasion by non-native species, frequently brought deliberately or accidently by people, which have disproportionate negative impacts on native species. Ireland has been invaded by four non-native small mammals: 1) the bank vole, 2) greater white-toothed shrew, 3) hazel dormouse and 4) field vole. These impact native fauna causing wood mouse population declines, pygmy shrew extirpation, changes in bird of prey productivity and a dramatic collapse of invertebrate biomass with probable trophic cascades likely affecting the wider ecosystem. The bank vole was first recorded in Northern Ireland at Crumlin near the Lough Neagh ASSI (Area of Special Scientific Interest) in 2020 and the field vole in Slievenacloy ASSI in 2023, and Slieveanorra and Croaghan ASSI in 2021; all designated for their biodiversity. The vector for these introductions is currently unknown. There is also reason to speculate that the greater white-toothed shrew may be present in Counties Fermanagh and Antrim, though this remains to be confirmed.

This project’s objectives include: 1) determining the current distribution, range and spread of non-native small mammals throughout Northern Ireland, 2) defining their ecology in terms of habitat use, environmental associations and diet and 3) quantifying their likely ecological impact.

The project is supported by local NGO, Ulster Wildlife (UW), whose research priorities are understanding the conservation needs of Northern Ireland priority species. Part of this project will focus on Slievenacloy Nature Reserve, owned and managed by UW, and the Crumlin area in which UW supports a barn owl recovery programme (where bank voles are owl prey). Further the project will engage with UW’s member and volunteer network in quality assured Citizen Science to collect relevant data to assist the wider understanding of the contemporary drivers of biodiversity loss.

This project relates directly to the Northern Ireland Environment Agency’s (NIEA’s) statutory responsibility to prevent, minimise and mitigate adverse impacts of non-native species under the EU Invasive Species Directive (Regulation EU1143/2014); adopted into local UK law post-Brexit. Moreover, NIEA reports on the status of native wildlife and habitats within designated sites under Article 17 of the EU Habitats and Species Directive (EU92/43/EEC), now locally Habitat Regulations Reporting. This research will support the UK’s biodiversity targets, including those related to the post-2020 Global Biodiversity Framework, which aims to halt species declines and protect vulnerable ecosystems whilst addressing the UN Sustainable Development Goal 15 (Life on Land), by contributing to biodiversity conservation.