The role of avian `seed predators' as seed dispersers

Authors: HELENO, RUBEN H.; ROSS, GEORGINA¹; EVERARD, AMY¹; MEMMOTT, JANE¹; RAMOS, JAIME A.²

Source: Ibis, Volume 153, Number 1, January 2011 , pp. 199-203(5)

Buy & download fulltext article:

Price: $48.00 plus tax (Refund Policy)

Abstract:

Seed dispersal is a central process in plant ecology with consequences for species composition and habitat structure. Some bird species are known to disperse the seeds they ingest, whereas others, termed `seed predators', digest them and apparently play no part in dispersal, but it is not clear if these are discrete strategies or simply the ends of a continuum. We assessed dispersal effectiveness by combining analysis of faecal samples and bird density. The droppings of seed dispersers contained more entire seeds than those of typical seed predators, but over a quarter of the droppings of seed predators contained whole seeds. This effect was further magnified when bird density was taken into account, and was driven largely by one frequent interaction: the Chaffinch Fringilla coelebs, a typical seed predator and the most abundant bird species in the area and dispersed seeds of Leycesteria formosa, a non-native plant with berry-like fruits. These results suggest the existence of a continuum between seed predators and seed dispersers.

Keywords: Azores; Chaffinch; continuum; dispersal effectiveness; mutualism; seed dispersal

Document Type: Short communication

DOI: http://dx.doi.org/10.1111/j.1474-919X.2010.01088.x

Affiliations: 1: School of Biological Sciences, University of Bristol, Bristol BS8 1UG, UK 2: Institute of Marine Research (IMAR/CMA), Department of Life Sciences, University of Coimbra, PO Box 3046, 3001-401 Coimbra, Portugal

Publication date: 2011-01-01