title: Asymmetric density dependence shapes species abundances in a tropical tree community.
abstract: The factors determining species commonness and rarity are poorly understood, particularly in highly diverse communities. Theory predicts that interactions with neighbors of the same (conspecific) and other (heterospecific) species can influence a species' relative abundance, but empirical tests are lacking. By using a hierarchical model of survival for more than 30,000 seedlings of 180 tropical tree species on Barro Colorado Island, Panama, we tested whether species' sensitivity to neighboring individuals relates to their relative abundance in the community. We found wide variation among species in the effect of conspecific, but not heterospecific, neighbors on survival, and we found a significant relationship between the strength of conspecific neighbor effects and species abundance. Specifically, rare species suffered more from the presence of conspecific neighbors than common species did, suggesting that conspecific density dependence shapes species abundances in diverse communities.
authors.affiliation: National Center for Ecological Analysis and Synthesis, 735 State Street, Suite 300, Santa Barbara, CA 93101, USA. comita@nceas.ucsb.edu
authors.forename: Liza S
authors.initials: LS
authors.lastname: Comita
authors.forename: Helene C
authors.initials: HC
authors.lastname: Muller-Landau
authors.forename: Salomón
authors.initials: S
authors.lastname: Aguilar
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hubbell
mesh_terms: D001499:Bayes Theorem; D044822:Biodiversity; D017753:Ecosystem; D010176:Panama; D011156:Population Density; D036226:Seedlings / Q000254:growth & development; D013045:Species Specificity; D014197:Trees / Q000254:growth & development; D014329:Tropical Climate