title: Beta-diversity in tropical forest trees.
abstract: The high alpha-diversity of tropical forests has been amply documented, but beta-diversity-how species composition changes with distance-has seldom been studied. We present quantitative estimates of beta-diversity for tropical trees by comparing species composition of plots in lowland terra firme forest in Panama, Ecuador, and Peru. We compare observations with predictions derived from a neutral model in which habitat is uniform and only dispersal and speciation influence species turnover. We find that beta-diversity is higher in Panama than in western Amazonia and that patterns in both areas are inconsistent with the neutral model. In Panama, habitat variation appears to increase species turnover relative to Amazonia, where unexpectedly low turnover over great distances suggests that population densities of some species are bounded by as yet unidentified processes. At intermediate scales in both regions, observations can be matched by theory, suggesting that dispersal limitation, with speciation, influences species turnover.
authors.affiliation: Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002-0948, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Condit
authors.forename: Nigel
authors.initials: N
authors.lastname: Pitman
authors.forename: Egbert G
authors.initials: EG
authors.lastname: Leigh
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chave
authors.forename: John
authors.initials: J
authors.lastname: Terborgh
authors.forename: Robin B
authors.initials: RB
authors.lastname: Foster
authors.forename: Percy
authors.initials: P
authors.lastname: Núñez
authors.forename: Salomón
authors.initials: S
authors.lastname: Aguilar
authors.forename: Renato
authors.initials: R
authors.lastname: Valencia
authors.forename: Gorky
authors.initials: G
authors.lastname: Villa
authors.forename: Helene C
authors.initials: HC
authors.lastname: Muller-Landau
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Losos
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Hubbell
mesh_terms: D017753:Ecosystem; D004484:Ecuador; D004777:Environment; D005583:Fourier Analysis; D008954:Models, Biological; D010176:Panama; D010568:Peru; D011336:Probability; D014197:Trees / Q000145:classification / Q000254:growth & development; D014329:Tropical Climate