Climate Change Will Resize and Reshape Plant–Hummingbird Networks in the Atlantic Forest

ABSTRACT Aim To assess how climate change could reshape plant–hummingbird interaction networks in the Atlantic Forest by predicting shifts in species co‐occurrence and evaluating changes in network structure. Location Atlantic Forest, South America. Methods We used ecological niche modelling to predict changes in the co‐occurrence of plants and hummingbirds under climate change scenarios. Modelled networks were analysed to compare network metrics, such as network size, number of links, niche overlap and robustness, between present and future conditions. We also simulated species extinctions to assess network resilience. Results Future local networks showed lower species richness, reduced size, fewer links and shared partners, increased niche overlap and decreased robustness. While network robustness improved under simulated plant and secondary hummingbird extinctions, future networks exhibited reduced resilience to species loss. Plants had higher niche overlap than hummingbirds, making them more vulnerable to secondary extinctions driven by hummingbird losses. Main Conclusions Climate change is expected to drive shifts in species co‐occurrence, leading to novel assemblages and structural changes in plant–hummingbird interaction networks. These alterations will likely decrease network robustness and resilience, highlighting potential cascading effects on ecosystem function. Our findings contribute to understanding the impacts of climate change on mutualistic networks and ecosystem stability in the Atlantic Forest and beyond.