title: IsMarkhamia lutea's abundance determined by animal foraging?
abstract: Understanding the determinants of tropical forest tree richness and spatial distribution is a central goal of forest ecology; however, the role of herbivorous mammals has received little attention. Here we explore the potential for red colobus monkeys (Procolobus rufomitratus) to influence the abundance ofMarkhamia luteatrees in a tropical forest by feeding extensively on the tree's flowers, such that this tree population is not able to regularly set fruit. Using 14 years of data from Kibale National Park, Uganda, we quantifyM. luteaflower and fruit production. Similarly, using 21 years of data, we quantify temporal changes in the abundance of stems in size classes from 1 m tall and above. Our analyses demonstrate thatM. luteais rarely able to produce fruit and that this corresponds to a general decline in its abundance across all size classes. Moreover, using 7 years of feeding records, we demonstrate that red colobus feed onM. lutea, consuming large amounts of leaf and flower buds whenever they were available, suggesting that this behavior limits fruit production. Therefore, we suggest that red colobus are presently important for structuring the distribution and abundance ofM. luteain Kibale. This dynamic raises the intriguing question of how a largeM. luteapopulation was able to originally establish. There is no evidence of a change in red colobus population size; however, if this old-growth forest is in a non-equilibrium state,M. luteamay have become established when red colobus ate a different diet.
authors.affiliation: McGill School of Environment and Department of Anthropology, McGill University, Montreal, Quebec, Canada H3A 2T7 and Wildlife Conservation Society, Bronx, New York, USA.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Chapman
authors.forename: Tyler R
authors.initials: TR
authors.lastname: Bonnell
authors.forename: Raja
authors.initials: R
authors.lastname: Sengupta
authors.forename: Tony L
authors.initials: TL
authors.lastname: Goldberg
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Rothman
keywords: Herbivory; Kibale National Park; Non-Equilibrium State; Seed Dispersal; Tree Mortality