CLIMIT: CLimate change impacts on Insects and their MITigation

Insects react rapidly to environmental change: for example, regional extinction rates of European butterflies have exceeded those of birds and higher plants by an order of magnitude in recent decades. We have also shown that butterflies are accurate indicators of change in less conspicuous invertebrate groups, including dominant insects such as ants that have major impacts on all other species in their environment. Here we propose to measure the combined impacts of human-induced changes in climate and habitat (area, isolation, patch quality) on some of Europe's most specialised and threatened grassland insects that interact with ants ('myrmecophiles' such as Adonis, Chalkhill, Silver-studded and 5 species of Large Blue butterflies, and two hoverflies whose young stages live 2 years inside ant nests), by studying their local adaptations, changing niches and different needs across a gradient of local climates from the Mediterranean to the North/Baltic seas. We will model the processes that limit each system's (meta-)populations, and predict the impacts of future scenarios of land-use, climate and socio-economic change in different regions. We will make new predictions, based on mathematical models, about how to mitigate the harmful impacts of multiple drivers of biodiversity change, and we will test our recommendations using existing and new large scale experiments of nature reserves and other conservation sites where the soil depth, topography and grazing management have been altered to create our current definitions of the optimum habitat for the Large blue and other butterflies, and the ants on which they depend. Finally, we will draw general conclusions about the changing needs of myrmecophiles, of which perhaps 100,000 species exist globally, including a disproportionate number of Red Book species, and of non myrmecophilous butterflies, in the latter case through comparing our model predictions with patterns of recorded change in all (UK) or representative (European) species across the climatic gradient, using the Centre for Ecology & Hydrology's dataset of annual changes in all UK butterfly population sizes since 1976, and other national and European datasets available to the consortium. A summary of the detailed hypotheses and objectives of this extensive proposal can be found in the main proposal on VR and in a shorter version under objectives on this form.