Habitat loss, dispersal, and the probability of extinction of tree species.

Ecological studies show that species not equally decline following habitat destruction, and suggest that underlying biological processes, such as dispersal type, might be determining the ecological sensitivity of species to habitat loss. There is, however, uncertainty as to how these mechanisms scale up to large scales and generalize across ecosystem types and processes, especially in plants. Using data from approximately 90,000 forest survey plots covering Peninsular Spain, we explored the patterns of variation in the probability of occurrence of 34 common tree species to decreasing levels of local forest cover. Decreased forest cover had a strong negative effect on tree diversity, but the responses of individual species were highly variable. Interestingly, animal-dispersed species were less vulnerable to habitat loss than wind-dispersed species. However, the latter is true provided that animal dispersers persist in the forest system. These results highlight the importance of plant-animal interactions in preventing the collapse of forest communities under habitat destruction.