Projected Climate Change Scenarios Spatially Decouple Desert Extrafloral Nectary–Bearing Plant–Ant Interactions

Aim Climate change is altering species distributions globally, but predicting the impacts on assemblages and their spatial overlaps under future scenarios remains an ongoing challenge. Here, we explore how climate change influences distributions among two interacting assemblages. Location The Mojave and Colorado Deserts, California, United States. Methods We developed stacked species distribution models for the community of extrafloral nectar (EFN)–bearing plants and the nectar‐feeding ant community and projected these models under two future climate scenarios. To assess the robustness of interactions between these communities to spatial mismatches, we examined potential shifts in geographic overlap between the EFN‐bearing plants and ant species under both scenarios. We analysed the bioclimatic factors influencing the distribution of both the plant and ant communities, as well as their responses to future climate change. We then explored whether climatic niche breadth and phylogeny could account for the differential responses of species to climate change. Lastly, we evaluated the significance of the EFN community on ant species distributions by determining whether the inclusion of EFN plants in ant distribution models enhances their predictive accuracy. Results The species richness of both the EFN‐bearing plant communities and ant communities decreased under both predicted climate change scenarios. The geographic overlap between EFN plants and ants significantly decreased under both future scenarios. The response of different ant species to climate change varied based on their climatic generalisation, but not their evolutionary relationships. Including the EFN plant community as a predictor in the species distribution models for ants improved their predictive performance. Main Conclusions The EFN plant community is an important driver of the geographic distribution and diversity of the nectar‐feeding ant community. More climatically generalised ant species benefit from the changing climate, whereas the EFN‐bearing plants are uniformly and negatively impacted, despite climate breadth. Despite the range increase of some ant species across the Mojave and Colorado Deserts, interactions between the groups are vulnerable to climate change because of the decrease in geographic overlap between pairs of ant and EFN‐bearing plant species.