Climate change and alpine-adapted insects: modelling environmental envelopes of a grasshopper radiation

Mountains create steep environmental gradients that are sensitive barometers of climate change. We modelled the environmental envelopes of twelve predominantly alpine, flightless grasshopper species in Aotearoa New Zealand, using current conditions and two future global climate change scenarios: representative concentration pathway (RCP) 2.6 (1.0 °C raise) and RCP8.5 (3.7 °C raise). Two thirds of our models suggested a reduced potential range across species by 2070, but surprisingly, for six species we predict an increase in potential suitable habitat under mild (+1.0°C) or severe global warming (+3.7°C). However, when we consider the limited dispersal ability of these grasshoppers, all twelve species studied are predicted to suffer extreme reductions in range, with a quarter likely to go extinct due to a 96-100% reduction in suitable habitat. Alpine species are particularly vulnerable to the impacts of climatic shifts, and species that have limited migratory ability will be particularly at risk of habitat loss, fragmentation and local extinction. Here we present the predicted outcomes for an endemic radiation of alpine taxa as an exemplar of the challenges that alpine species, both in New Zealand, and internationally, will face in light of anthropogenic climate change