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

Evidence is presented for the importance of western lowland gorillas as see d dispersers in the Lope Reserve, Gabon. The survival and growth of seedlin gs 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 betw een this and seeds (i) deposited in dung on gorilla feeding trails, (ii) dr opped (spat out) under conspecific canopies, and (iii) scatter-dispersed (s pat out) by other consumers away from conspecific trees but under intact fo rest 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 veg etation conditions: better performance was observed in seedling clumps with less vegetation cover. Gorillas at Lope apparently provide high quality se ed dispersal for these species, not just because they consume large quantit ies of seeds, but because the pattern of seed deposition, especially in nes t sites, can result in the enhanced survival and growth of seedlings.