Beta-diversity in tropical forest trees.
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.
Condit
Richard
R
Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Unit 0948, APO AA 34002-0948, USA.
Pitman
Nigel
N
Leigh
Egbert G
EG
Chave
Jérôme
J
Terborgh
John
J
Foster
Robin B
RB
Núñez
Percy
P
Aguilar
Salomón
S
Valencia
Renato
R
Villa
Gorky
G
Muller-Landau
Helene C
HC
Losos
Elizabeth
E
Hubbell
Stephen P
SP
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