Testing consistency of modelled predictions of the impact of climate change on bats

Species Distribution Models (SDMs) are a cornerstone of climate change conservation research but temporal extrapolations into future climate scenarios cannot be verified until later this century. One way of assessing the robustness of projections is to compare their consistency between different modelling approaches, placing more confidence on consistent rather than inconsistent predictions, especially if they are consistent with recent population trajectories. We compared predicted climate change impacts on nine bat species throughout their European ranges (using SDMs) and their activity (using GLMMs) within Ireland as a focal study region. Five species (N. leisleri, P. nathusii, P. pipistrellus, P. pygmaeus and P. auritus) were predicted to have stable ranges throughout the 21st century with projected increases in activity consistent with recently observed population increases. M. daubentonii and R. hipposideros are also likely to have stable European ranges throughout the 21st century but models predicted a negative impact of climate change on activity in Ireland contrasting with a stable population trend in M. daubentonii and an increasing trend in R. hipposideros over recent decades. M. nattereri was predicted to maintain its range extent while M. mystacinus was predicted to undergo range contraction by the end of the 21st century under a high greenhouse gas emissions scenario. We propose there is utility in comparing predicted trajectories from climate change impact models using different parameters (e.g. range versus activity). Our predictions should inform government and conservation organisations when creating future climate change conservation policy.