The role of dispersal by granivorous and omnivorous waterbirds in MTEs

Abstract

Whereas most attention is paid to frugivory, we must not overlook the importance of omnivorous, granivorous and herbivorous waterbirds as vectors of a broad range of native and alien plants in natural and artificial Mediterranean ecosystems. We exemplify their importance by illustrating the role of ducks, geese, shorebirds and gulls in dispersing terrestrial and aquatic plants within and between ricefields, salinas and natural wetlands. Endozoochory is more important than epizoochory, and is a dispersal mechanism for plants classically assumed to have no or other means of dispersal (i.e. for plants not assigned to the ¿endozoochory syndrome¿). Hence the capacity for long-distance dispersal is widely underestimated for these plants. The role of migratory granivorous waterbirds is likely to be extremely important both in the spread of alien plants within MTEs and in allowing native plants to keep pace with climate change. Seed dispersal disruptions are occurring in MTEs through the loss of natural wetlands, declines of vector populations and short-stopping (contraction of migration routes) in response to global change.