title: Negative density dependence of seed dispersal and seedling recruitment in a neotropical palm.
abstract: Negative density dependence (NDD) of recruitment is pervasive in tropical tree species. We tested the hypotheses that seed dispersal is NDD, due to intraspecific competition for dispersers, and that this contributes to NDD of recruitment. We compared dispersal in the palm Attalea butyracea across a wide range of population density on Barro Colorado Island in Panama and assessed its consequences for seed distributions. We found that frugivore visitation, seed removal and dispersal distance all declined with population density of A. butyracea, demonstrating NDD of seed dispersal due to competition for dispersers. Furthermore, as population density increased, the distances of seeds from the nearest adult decreased, conspecific seed crowding increased and seedling recruitment success decreased, all patterns expected under poorer dispersal. Unexpectedly, however, our analyses showed that NDD of dispersal did not contribute substantially to these changes in the quality of the seed distribution; patterns with population density were dominated by effects due solely to increasing adult and seed density.
authors.affiliation: Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Ancon, Republic of Panama; Department of Environmental Sciences, Wageningen University, PO Box 47, 6700 AA, Wageningen, The Netherlands; Community and Conservation Ecology group, University of Groningen, PO Box 11103, 9700 CC, Groningen, The Netherlands.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Jansen
authors.forename: Marco D
authors.initials: MD
authors.lastname: Visser
authors.forename: S
authors.initials: S
authors.lastname: Joseph Wright
authors.forename: Gemma
authors.initials: G
authors.lastname: Rutten
authors.forename: Helene C
authors.initials: HC
authors.lastname: Muller-Landau
mesh_terms: D028023:Arecaceae / Q000502:physiology*; D008954:Models, Biological; D010176:Panama; D011156:Population Density; D058614:Seed Dispersal / Q000502:physiology*; D036226:Seedlings / Q000502:physiology*; D014329:Tropical Climate
keywords: Clumping; Janzen-Connell; competition for dispersers; escape; intraspecific competition; population regulation; recruitment limitation; seed limitation; species coexistence; tropical forest