Biotic interactions under risk: climate change drives spatial mismatch between a critically endangered tree and its seed dispersers and predators

Climate change impacts biodiversity through shifts in species distributions and changes in the composition of biological communities. However, the effects of these changes on the spatial association between species are poorly understood. In this study, we examined the effects of climate change on the distribution mismatch between Araucaria angustifolia (araucaria), a critically endangered keystone species in the Brazilian Atlantic Forest hotspot, and its community of seed dispersers and predators. Ecological niche models were employed to compare the distribution of A. angustifolia with the projected distributions of its dispersers and predators under two different climate change scenarios. Our projections revealed species-specific responses to climate change, resulting in varying levels of spatial mismatch between A. angustifolia and its dispersers and predators. Notably, significant changes in the spatial mismatch compared to current conditions were projected for 70% of the seed dispersers and 83% of the seed predators. Interestingly, our projections demonstrated a discernable pattern in the changes in richness of dispersers and predators within the distribution range of A. angustifolia, indicating a potential risk of imbalance in seed dispersal and predation in certain regions. Using ecological niche modeling techniques, our study highlights that the climate-driven decoupling of geographical distributions may contribute to the disruption of biotic interactions, with potential implications for the conservation of A. angustifolia and the fauna dependent on its seeds as a food source. These findings emphasize the importance of considering the indirect effects on biotic interactions when assessing the impacts of climate change on biodiversity.