Conservation management for myrmecophiles on large-scale sites & within landscapes; Model potential for mitigation under global change

We believe it important to demonstrate that research and models of the sort we propose can be successfully applied to conservation. Three iconic Habitats Directive species of Maculinea have already provided a rare opportunity to test recent ideas through large-scale restorations, albeit under a limited range of current climates. We will analyse their success.

Maculinea arion: In parallel with Biodiversa, CEH and Oxford will measure the changing vegetation structure and density of Thymus, Myrmica and M. arion populations on the oldest restoration sites in 2009-12, testing model predictions which, to date, explain 81% of 75 observed population changes on 13 sites. Here we propose to study recent attempts to create new fully-functioning ecosystems on ley grassland. New habitats were established and attributed to different management treatments. On all sites and plots, we will measure vegetation structure, soil microclimate, and their colonization by all plants, all ants, M. arion and selected soil and grassland invertebrates.

Maculinea nausithous and M. teleius: Replicated experiments began in Bavaria in 2003 to compare the effect of different mowing regimes (cut twice a year or every 1, 2, 5 years). Related management experiments have been conducted in the warmer Rhone valley since the 1990th. We will make standardized measurements of foodplant density, phenology and flower-head growth-form in each treatment in both regions, and of the species and density of ants, Maculinea butterflies and Neotypus parasitoids. The results should not only measure the apparent success of these experiments, but also improve model parameters describing the management regime, vegetation structure and habitat dynamics that generate optimum or suboptimal source habitat for both community modules under two climates.

A key outcome of CLIMIT will be to simulate practices that may reverse, mitigate or simply delay the more harmful impacts of predicted future land use and climate warming, buying time for species to adapt to new environments or migrate to cooler ones. Given the scale of recent agri-environmental schemes to enhance biodiversity in European grasslands, it is not fanciful to imagine that three additional elements – variable micro-topography, later seral stages of vegetation, and habitat creation – might be added as standards in the management recommendations of future schemes. To achieve this we must first quantify how effectively local climate can be modified through micro-topography and vegetation structure, and how quickly insects can counter short-term changes by exploiting cooler, moister examples of their fundamental niches. From our anecdotal observations, we suspect that for populations inhabiting the cooler half of a species’ (or genotype’s) range, the rate at which temperatures rise (or other climate parameters change) to levels beyond the limit of local tolerance can be at least halved if cooler alternative niches exist nearby.

In this final research sub-project we will construct a holistic model, integrating the data from all earlier WPs, to explore the extent and time-scale at which the combined deleterious impacts of future climate and land-use changes might be mitigated for the threatened study species by changing site micro-topographies and seral stages. We will also attempt a more general model incorporating attributes of a wider range of insects and plants. The aim, in both cases, will be to generate effective, practical advice for a wide range of European end-users.