Assessment of impacts of future scenarios of climate and land-use change on current European races of insects and ecosystems

The aim of the first part of this work package is to investigate whether phenology in butterflies has changed during the past 30 years. In particular changes to edge-of-range-populations and their consequences for the persistence of populations will be examined.

Temporal or spatial desynchronisation is a key threat to any module of interacting species. Of our study systems, the Maculinea are most likely to be affected since they depend upon food plants in a brief phenological condition coexisting within 1-2m with suitable host ants. One empirical study will investigate synchrony between Maculinea arion and its host plants and host ants on several sites in the UK. Results will be incorporated in existing mechanistic models of M. arion that explain its population dynamics well on warmer UK sites, to predict how often an uncoupling of phenologies may result in local extinction under future climates. Further, grid-based models will be used to examine changes in small scale spatial distributions of Maculinea foodplants and ants under extreme weather or climate change, accounting for foodplant and butterfly phenology to explore the risk of temporal desynchronization and thus fewer oviposition options.

We will use the metapopulation model (see WP2) to investigate the probability of myrmecophilous systems to disperse under changed environment or climates. Specifically we address the hypothesis that (i) mutualistic systems are threatened by climate change as innovative, better-adapted genes are unlikely to be available in the local gene pool or to immigrate; and (ii) a similar threat may exist for the most integrated social parasites, but for different reasons.

We apply several models to study the population dynamics of different myrmecophiles when fitness and habitat availability alter due to land use and climate changes. For this purpose already established models which describe the population dynamics of Maculinea will be adapted so that habitat and weather/climate impact independently, bottom-up, on ant fitness. We will then enter data from WP 1 of variation in the fundamental niches of all interacting species, to simulate the availability of habitat and species’ population dynamics in each system under different European climates. We will examine whether climate warming increases habitat area, connectivity and population stability near current northern range limits of species, but amplifies declines further south. We will explore the sensitivity of populations to combinations of climate and land-use change using the most realistic socio-economic scenarios for Europe.