Effects of habitat and climate change on conservation of the Lulworth Skipper butterfly

There is an urgent need to understand the effects of climate change on wildlife conservation. In a changing climate, Britain's role in conservation will increase for species whose range elsewhere becomes too warm or dry. Yet there is little evidence of how habitat management can help these species survive and spread as the climate warms. This project will apply new field research and computer modelling to a unique dataset, to test how landscape-scale conservation can help one of Britain's rarest butterflies respond to climate change. The CASE partner Butterfly Conservation is the leading UK invertebrate conservation charity, with a strong record of collaborative research.

In Britain, The Lulworth Skipper butterfly is restricted to Dorset. The species has declined throughout Europe, where much of its range could become unsuitable by 2080 as the climate warms. In Britain, warming is expected to favour the species, but both the size and number of its populations have declined since 1978. The student will validate causes of decline, and propose methods to reverse them, contributing to scientific understanding and Butterfly Conservation's activity in four areas:

1. Climatic effects on skipper butterflies
Conservationists need stronger evidence for the interacting effects of habitat and climate change on species populations. The student will use more than three decades of counts from the UK Butterfly Monitoring Scheme to test the factors influencing populations of three closely related butterflies sharing many ecological features (Small, Essex and Lulworth Skippers). We will develop statistical models to predict flight periods (phenology) and population sizes of each species, to establish how these are influenced by regional weather, local topography and vegetation, exploring why the species show closely correlated recent declines despite expected positive responses to warming in Britain.

2. Metapopulation dynamics at species range margins
Like many species, Lulworth Skippers survive in Britain as networks of populations in fragmented habitats (metapopulations). Understanding the factors influencing colonisation and extinction in metapopulations is vital for landscape-scale conservation, and to allow species to persist and expand their distributions as the climate warms. The student will model factors influencing colonisation and extinction, making use of surveys of all populations of the Lulworth Skipper in 1978, 1997, 2010, and a new survey in 2017. New analyses using this unique dataset will allow conclusions to be drawn about the roles of climate, microclimate, and the area, quality and isolation of habitat in conservation planning for this and other species.

3. Adapting management to environmental change
Testing how management practices affect populations of rare species is essential for evidence-based conservation. Management can modify effects of environmental change on the growth and survival of species either directly, by exposure to changed microclimates, or indirectly by changes to species interactions, such as the quality of food. The student will test effects on microclimate, the nutritional quality of food plants, and on Lulworth Skipper egg-laying, larval growth and survival, of management regimes in experimental plots. Results will show how habitat mediates effects of environmental change on species, and will contribute directly to conservation management via our links to Butterfly Conservation and land managers.

4. Maintaining habitat variety for landscape-scale conservation
Creating a diversity of habitats with different management regimes has been proposed as a tool to increase resilience to climate change, but rarely tested. The student will model whether varied management can help Lulworth Skipper persist and spread in Britain under climate change, providing evidence and understanding for the landscape-scale conservation of this and other species.