Spotswood, E. N., UC Berkeley, Berkeley , USA, espots@berkeley.edu
Bartolome, J. W., UC Berkeley, Berkeley, USA, jwbart@berkeley.edu
Meyer, J. Y., Delegation of Research , Papeete, French Polynesia, jean-yves.meyer@recherche.gov.pf

BIRDS IN SEED DISPERSAL WEBS: CONSEQUENCES FOR NATIVE COMMUNITIES AND SPECIES INVASIONS IN FRENCH POLYNESIA

Mutually beneficial relationships such as seed dispersal by frugivorous birds are crucial to the maintenance of biodiversity on Earth. Arrival of introduced organisms can disrupt these relationships triggering cascading consequences for native communities. In the tropical high islands of French Polynesia, three frugivores disperse the seeds of many plants, both native and exotic. We investigated the network of relationships between frugivores and fruit bearing plants on the islands of Tahiti and Moorea. Bird diet was determined through analysis of fecal samples. Seed viability was assessed with germination tests with seeds extracted from intact fruits and fecal samples. Our results show that exotic organisms are highly integrated into native dispersal webs. Exotic plants benefit from dispersal by birds which transport seeds long distances and deposit them intact. Native plants show enhanced germination after digestion by native frugivores highlighting the important role of dispersal. Native frugivores consume many exotic species which provide a highly abundant and continuously available resource. These indirect impacts of species invasions are likely to be detrimental to the regeneration of native forests.

Oral presentation

Session #:G15
Date: Monday, 8 February 2010
Time: 10:45

Presentation is given by student: Yes

Presenting authors are underlined.