Limited potential for bird migration to disperse plants to cooler latitudes

Climate change is forcing the redistribution of life on Earth at an unprecedented velocity(1,2). Migratory birds are thought to help plants to track climate change through long-distance seed dispersal(3,4). However, seeds may be consistently dispersed towards cooler or warmer latitudes depending on whether the fruiting period of a plant species coincides with northward or southward migrations. Here we assess the potential of plant communities to keep pace with climate change through long-distance seed dispersal by migratory birds. To do so, we combine phenological and migration information with data on 949 seed-dispersal interactions between 46 bird and 81 plant species from 13 woodland communities across Europe. Most of the plant species (86%) in these communities are dispersed by birds migrating south, whereas only 35% are dispersed by birds migrating north; the latter subset is phylogenetically clustered in lineages that have fruiting periods that overlap with the spring migration. Moreover, the majority of this critical dispersal service northwards is provided by only a few Palaearctic migrant species. The potential of migratory birds to assist a small, non-random sample of plantsto track climate change latitudinally is expected to strongly influence the formation of novel plant communities, and thus affect their ecosystem functions and community assembly at higher trophic levels.

Automated summary

Climate change is rapidly affecting the redistribution of life on Earth, with migratory birds playing a crucial role in helping plants track climate change through seed dispersal. However, the direction of seed dispersal by birds can vary depending on the fruiting period of plant species and the direction of their migration. The study found that most plant species in European woodland communities are dispersed by birds migrating southward, with only a few species being dispersed by birds migrating northward, indicating a potential impact on the formation of novel plant communities and their ecosystem functions.