When species can't keep up: evaluating landscape conservation actions needed under climate change

Biodiversity is threatened by land-use change and climate change; some species are failing to track suitable climate because their habitat is too scarce and fragmented. The grizzled skipper butterfly, Pyrgus malvae, exemplifies species that may have a critical need for "stepping stones", but where the habitat which is feasible to restore might be of low quality. This species is currently found most abundantly on calcareous grasslands in southern England, but can occur at variable density on mesic grasslands, woodland clearings, and brownfield sites, dependent on host plant abundance and microclimate conditions. Climate envelope models predict that it should be expanding northwards with recent climate change. However, nationwide monitoring shows no northward shift and widespread decline in population numbers. This project will elucidate the interaction between habitat availability and climate suitability for grizzled skipper at its northern range margin in central Britain, with a focus on the effectiveness of potential habitat restoration strategies.
This project aims to achieve the following objectives through a combination of fieldwork, spatial statistics and population modelling:
1 Define the habitat quality of selected brownfield sites, grasslands and woodland clearings for grizzled skipper in terms of host plant abundance and microclimate.
2 Explore, using dynamic distribution models, the importance of habitat availability in predicting grizzled skipper distributions.
3 Test by simulation the impact of future land-use scenarios on the ability of the grizzled skipper to track climate change. Specifically, to test the impact of (a) small numbers of high quality habitat patches versus larger numbers of lower quality patches and (b) opportunistic arrangements versus strict spatial targeting to create connected chains.