Journal of Tropical Ecology



Gorillas and seed dispersal in the Lopé Reserve, Gabon. II: Survival and growth of seedlings


Benedict C.  Voysey a1a2p1, Karen E  McDonald a1, M. Elizabeth  Rogers a2, Caroline E. G.  Tutin a1 and Richard J  Parnell a1
a1 Station d'Etudes des Gorilles et Chimpanzés (SEGC), BP 7847, Libreville, Gabon
a2 Institute for Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, UK.

Abstract

Evidence is presented for the importance of western lowland gorillas as seed dispersers in the Lopé Reserve, Gabon. The survival and growth of seedlings of three tree species, growing from dung deposited at gorilla nest sites, were monitored for up to 2 y after deposition. A comparison was made between this and seeds (i) deposited in dung on gorilla feeding trails, (ii) dropped (spat out) under conspecific canopies, and (iii) scatter-dispersed (spat out) by other consumers away from conspecific trees but under intact forest canopy. The highest survival and the best performance of seedlings was always at a gorilla nest site, although not every site was favourable for survival or growth. Seedling performance was related to the surrounding vegetation conditions: better performance was observed in seedling clumps with less vegetation cover. Gorillas at Lopé apparently provide high quality seed dispersal for these species, not just because they consume large quantities of seeds, but because the pattern of seed deposition, especially in nest sites, can result in the enhanced survival and growth of seedlings.

(Accepted July 20 1998)


Key Words: gorilla; regeneration; seed dispersal; seedlings; tropical forest.

Correspondence:
p1 Present address: LTS International Ltd, Pentlands Science Park, Bushloan, Penicuik, Edinburgh EH26 0PH, UK (ben-voysey@ltsi.co.uk