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 calibrated 10 statistical models to formulate ensemble ecological niche models for 12 predominantly alpine, flightless grasshopper species in Aotearoa New Zealand, using their current distributions and current conditions. Niche models were then projected for two future global climate scenarios: representative concentration pathway (RCP) 2.6 (1.0 degrees C rise) and RCP8.5 (3.7 degrees C rise). Results were species specific, with two-thirds of our models suggesting a reduction in potential range for nine species by 2070, but surprisingly, for six species, we predict an increase in potential suitable habitat under mild (+1.0 degrees C) or severe global warming (+3.7 degrees C). However, when the limited dispersal ability of these flightless grasshoppers is taken into account, all 12 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. Habitat loss is associated with habitat fragmentation that is likely to escalate stochastic vulnerability of remaining populations. 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, are subject to by anthropogenic climate change.

Automated summary

Mountains serve as sensitive indicators of climate change, and their environmental gradients have a significant impact on biodiversity. This study used statistical models to predict potential habitat changes for 12 flightless grasshopper species in New Zealand's alpine regions. The results indicate that due to habitat loss, the range of these species will significantly decrease, and some may even face extinction.