Autor(es):
Costa, Jose M. 
; Ramos, Jaime A. ; da Silva, Luís P. ; Timoteo, Sergio ; Araujo, Pedro M. ; Felgueiras, Marsial S. ; Rosa, Antonio ; Matos, Claudia ; Encarnaçao, Paulo ; Tenreiro, Paulo Q. ; Heleno, Ruben H.
Data: 2014
Identificador Persistente: http://hdl.handle.net/10316/25247
Origem: Estudo Geral - Universidade de Coimbra
Assunto(s): Long-Distance Dispersal; Seed Dispersal; Farmland Birds; Exotic Seeds; Feathers; Islands
Descrição
Fruits and seeds are critical food sources for many European passerines during the autumn migration, which in turn contribute
to disperse seeds either internally, i.e. after ingestion (endozoochory), or externally, when seeds adhere to the body
surface (epizoochory). Despite the recognized importance of birds as seed dispersers, the vast majority of studies focused
on endozoochory while the external transport of seeds is frequently invoked as being potentially important, but remains
largely unexplored. Th is is particularly important during the post-breeding migration of passerines, the most ubiquitous
and diverse movement of potential seed carriers across Europe and into Africa, which coincides with the fruiting peak of
many plant species (August – October). Our aim was to evaluate the role of migrating birds as potential long-distance seed
dispersers, and comparing the prevalence of epizoochory and endozoochory during post-breeding migration. We sampled
926 wild birds in nine locations in Portugal, and retrieved 1833 seeds of 19 plant species dispersed internally and only three
seeds externally attached to three birds ( Serinus serinus , Locustella naevia and Turdus merula ), showing an endozoochory
prevalence 85 times higher than that of epizoochory. Migrating and non-migrating passerines dispersed seeds equally.
While two of the seeds transported externally had specifi c adaptations to epizoochory, namely spines ( Torilis arvensis ) and
hooks ( Galium aparine ), the third is a large seed from a fl eshy-fruited plant, Frangula alnus (i.e. typical endozoochorous
syndrome). Th ese seeds were found on bird species with diff erent diets, but similar behaviour (ground foragers) and in
similar habitats (open agro-ecosystems). Our results highlight the strong role of migrating passerines as potentially longdistance
seed dispersers and show that, at least in the autumn, the prevalence of epizoochory is several orders of magnitude
lower than that of endozoochory.
