Robustness of plant-flower visitor webs to simulated climate change

Climate change threatens the integrity of pollination webs by decoupling plants and flower visitors both phenologically and ecologically. We simulated a range shift of flower-visitor species along a steep east-west rainfall gradient to explore resulting patterns of extinction. The systems studied seemed to be rather robust to range shifts. This results from (a) the positive correlation between the geographic range and both the local (i.e. at each site) and the regional (i.e. pooling across sites) number of interaction partners of the plants and flower visitors of these webs, and (b) a nested assembly of interactions at the regional level. In a broader context, this study reveals itself as a useful tool for understanding the links between the interaction pattern of mutualistic webs and their response to a major threat such as climate change.