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Grantee Research Project Results

NCER Grantee Research Project Results

Geographic Variation in Afrotropical Seed Dispersal Systems: A Case Study of the Myristicaceae

EPA Grant Number: U915157
Title: Geographic Variation in Afrotropical Seed Dispersal Systems: A Case Study of the Myristicaceae
Investigators: Whitney, Kenneth D.
Institution: University of California - Davis
EPA Project Officer: Broadway, Virginia
Project Period: January 1, 1997 through January 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology and Ecosystems

Description:

Objective:

The objective of this research project is to address the ecological consequences of geographic variation in tropical seed dispersal systems, in particular:

1. Does disperser assemblage composition change radically across the range of a particular plant species?

2. Do differing assemblages result in large differences in seed dispersal success?

3. How do differences in seed dispersal success affect the demographics of tree populations?

Approach:

The African nutmegs (family Myristicaceae) are a good model system for understanding geographic variation in seed dispersal. Preliminary data suggest that considerable geographic variation in nutmeg dispersal exists. In the Dja Reserve, four hornbill species (family Bucerotidae) are the most important dispersers of this family. Because only one of these hornbill species occurs on the island of Bioko, Equatorial Guinea, it is clear that the dispersal systems of nutmegs on Bioko are different from that of the nutmegs on the African mainland. I will be expanding the study of Myristicaceae dispersal (begun in 1994 at a single site in Cameroon) to several mainland sites in Cameroon and at least one site on Bioko. At each site, disperser assemblage composition will be determined through observations of animals at each of several study trees through tree watches. Fruit crop size and seed dispersal success will be estimated using plastic fruit traps. Fruits from each study tree will be collected and preserved in ethanol. Collected fruits will be analyzed for nutritional content to determine the effects of fruit quality on disperser assemblages and seed dispersal success. Each study tree will be mapped in relation to other nearby fruiting trees. These data will be used to determine the effect of neighborhood (ecological setting) in disperser assemblage composition and seed dispersal success. Finally, the consequences of dispersal will be evaluated with seed and seedling transects radiating out from study trees. Seed and seedling mortality will be assessed over a 3-year period at each site.

Supplemental Keywords:

fellowship, Afrotropical seed dispersal systems, seed dispersal systems, myristicaceae, African nutmegs, nutmegs.

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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