|dc.contributor.author||Smith, Thomas B.
Parker, V. Thomas
Hardesty, Britta Denise
Stauffer, Donald J.
Holbrook, Kimberly M.
Lamperti, Aaron M.
Fogiel, Mark K.
Whitney, Kenneth D.
Seed dispersal is a process critical to the maintenance of tropical
forests, yet little is known about the interactions of most dispersers with their
communities. In the Dja Reserve, Cameroon, seed dispersal by the hornbills Ceratogymna
atrata, C. cylindricus and C. fistulator (Aves: Bucerotidae) was evaluated with
respect to the taxonomic breadth of plants dispersed, location of seed deposition
and effects on seed germination. Collectively, the three hornbill species consumed
fruits from 59 tree and liana species, and likely provided dispersal for 56 of them.
Hornbill-dispersed tree species composed 22% of the known tree flora of the site.
Hornbill visit lengths, visit frequencies, and seed passage times indicated that few
seeds were deposited beneath parent trees; in five hornbill/tree species pairings
studied, 69–100% of the seeds ingested were deposited away from the parent trees.
Germination trials showed that hornbill gut passage is gentle on seeds. Of 24 tree
species tested, 23 germinated after passage by hornbills; of 17 planted with controls
taken directly from trees, only four species showed evidence of inhibition of
germination rate, while seven experienced unchanged germination rates and six
experienced enhanced germination rates. Results suggested that Ceratogymna hornbills
rank among the most important seed dispersers found in Afrotropical forests,
and they deserve increased conservation attention. Ceratogymna hornbills are likely
to become increasingly important in forest regeneration as populations of larger
mammalian seed dispersers (such as forest elephants and primates) diminish.
NYZS/The Wildlife Conservation Society, the National Science Foundation
Graduate Fellowship Program, the GAANN Program of San Francisco State
University, and ECOFAC Cameroun
Cambridge University Press
Seed dispersal by Ceratogymna hornbills in the Dja Reserve, Cameroon