Dissertation Research: Using networks to understand seed dispersal mutualisms and the impacts of invasive species on remote oceanic islands in French Polynesia

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

As an indirect effect of consuming fruit, birds often transport plant seeds to locations distant from the original plants. This dispersal is critical for plants that cannot move their seeds without assistance. In the context of a community, the connections between birds and plants are analogous to social networks, with nodes representing plant species that are connected by the links (bird dispersal) between them. The arrival of invasive species can alter the connections between native species, disrupting these critical relationships. This project investigates how species invasions are altering the structure of seed dispersal networks in French Polynesia. Birds will be captured and fecal samples collected in order to characterize diet on two islands that vary in the degree of invasion by a fruit-bearing tree. Additionally, experiments with birds in aviaries will be used in order to discover how the abundance of an invasive species influences the dietary decisions of birds, and thus the role birds play in seed dispersal. The control of invasive species is one of the most critical conservation issues facing resource managers globally. This project will inform invasive species control in French Polynesia through collaboration with local scientists and managers. The investigators provide data to two offices in the French Polynesian government. The project is also the first to gather systematic data on the status of a protected Fruit Dove, which is found on only a few islands in French Polynesia, providing information that is essential for conservation of this vulnerable species. Three French Polynesian and one American student will gain research experience while participating in field data collection, and one of the investigators is helping to develop curriculum and teaching in two classes of underprivileged 5th graders on the island of Moorea. The project is dedicated to developing close collaborative relationships with French Polynesian researchers, and provides tissue samples for the Moorea Biocode project, a program involving over 150 scientists from all over the world to DNA barcode every organism on the island of Moorea.