We characterized the disperser assemblage of four large-seeded (≥5mm) mature forest tree species in the Nyungwe National Park, Rwanda in order to evaluate frugivorous primate’s relative importance as seed dispersers of the defined tree species. Ekebergia capensis, Olea capensis, Prunus africana, and Syzygium guineense were observed over the course of their fruiting period for diurnal frugivore activity. In order to determine relative importance of a frugivore to a tree species we calculated an estimation of the total of the number of seeds dispersed away from the parent tree by frugivore category. Frugivores were divided into five categories including big birds, small birds, big primates, small primates, and squirrels. We calculated an average number of seeds dispersed per visit and then extrapolated to the total number of seeds dispersed over the observation period. Primates and birds primarily swallowed seeds or, in the case of Cercopithecus species, placed fruits in the cheekpouch prior to leaving the tree. Tree species were visited by similar frugivore categories but varied in the frugivore category with the greatest dispersal potential. Big birds dispersed proportionally less seeds per visit for Ekebergia and Prunus than small primates but were more frequent visitors dispersing the greatest number of seeds over the observation period. Similarly big primates dispersed more seeds of Syzygium per visit than other frugivore categories but were infrequently observed. These findings highlight the importance of aspects of quality (i.e. dispersal away from under the parent crown) and quantity (i.e. visitation frequency and group size) when trying to determine the predominant disperser of a tree species.
