Author's School

Graduate School of Arts & Sciences

Author's Department/Program



English (en)

Date of Award

Spring 4-29-2013

Degree Type


Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

Robert W Sussman


Western lowland gorillas: Gorilla g. gorilla) consume large quantities of fruit and disperse a great number of seeds. The majority these seeds are dispersed intact and viable in the dung. Dung is often deposited around the rim of a night nest or at a nest-site. Gorillas often construct nests in areas that have a sparse canopy, flattening the ground vegetation. These locations can be beneficial to the growth and survival of the seed species they disperse. Thus, not only are gorillas effective in terms of depositing seeds great distances from parent plants, away from the highest seed rain densities, they are also effective in directing seeds to potentially beneficial microsites.

The objective of this research was to develop an understanding of the spatial and temporal patterns in fruit availability, seed deposition, and adult plants, and to test whether these patterns relate to the ecology of seed dispersal by gorillas.

Results suggest that gorilla foraging and nesting behavior in particular, impose both spatial and temporal limitations to the distribution of dispersed seeds. In addition, temporal variation in the gorilla diet and factors that affect defecation rates and locations promote variation in the combinations: composition and abundance) of the seed species dispersed to different microsites.

The clustered distribution of nest-sites leads to clumped and spatially restricted seed deposition patterns. Recruitment in gorilla-dispersed seed species corresponds with the aggregated: clumped) distribution of nest-sites. Gorillas have a long-lasting effect on the spatial structure and floristic composition of the forests they inhabit, particularly in large-seeded species.


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