Date of Award

8-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Biological Sciences

Advisor

DeWalt, Saara J

Committee Member

Childress , Michael

Committee Member

Gerard , Patrick

Abstract

Agoutis are important seed dispersers as well as predators of numerous plant species in Neotropical continental rainforests, but little is known about their role as seed removers (dispersers and predators) on islands. We investigated seed removal of seven rain forest species on the island of Dominica in the Lesser Antilles by the entire seed-remover community and specifically by the Red-rumped Agouti, Dasyprocta leporina, a scatterhoarding rodent introduced to the island approximately 2500 years ago. We recorded removal rates in three regions of Dominica from 168 experimentally placed seed groups containing a total of 1356 seeds. Seed groups were either accessible to the entire seed-remover community or placed within exclosures designed to exclude agoutis. Within 13 days, 47 percent and 28 percent of seeds had been removed from control groups and agouti exclosure groups, respectively. Thus, agoutis were responsible for removal of 19 percent of seeds. Seed removal was greater in areas with higher regional conspecific adult densities regardless of treatment. Species with smaller seeds were preferentially taken by seed removers other than agoutis, whereas agoutis were responsible for the majority of the removal of the seeds of larger-seeded species. This introduced scatterhoarder clearly plays an important role in determining the movement and fate of seeds in Dominican rain forests, particularly for the largest-seeded species that much of the rest of the animal community does not disperse or consume.

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