Plant colonization: are wind dispersed seeds really dispersed by birds at larger spatial and temporal scales?

ABSTRACT. It is suggested that many plant species often thought of as wind dispersed may in fact be largely dispersed by animals, mostly birds, at larger spatial and temporal scales. This possibility is illustrated by using data on Holocene tree migrations in Europe. It is suggested that exploratory movements, often by young birds, may play an important role in such dispersal rather than the classic return migrations of birds. In the case of European trees there could have been active selection for rapid migrations occurring even in the glacial refugia sites in the mountains of southern Europe. Plant migration rates, and hence the ability to deal with climatic change, may have been lower before the evolution of a diverse avifanua. It is suggested that for many ‘wind dispersed’ seeds the wind dispersal mechanism is adapted to local dispersal (over distances of a few canopy diameters) and larger scale dispersion is due to birds.