title: Dispersal, environment, and floristic variation of western Amazonian forests.
abstract: The distribution of plant species, the species compositions of different sites, and the factors that affect them in tropical rain forests are not well understood. The main hypotheses are that species composition is either (i) uniform over large areas, (ii) random but spatially autocorrelated because of dispersal limitation, or (iii) patchy and environmentally determined. Here we test these hypotheses, using a large data set from western Amazonia. The uniformity hypothesis gains no support, but the other hypotheses do. Environmental determinism explains a larger proportion of the variation in floristic differences between sites than does dispersal limitation; together, these processes explain 70 to 75% of the variation. Consequently, it is important that management planning for conservation and resource use take into account both habitat heterogeneity and biogeographic differences.
authors.affiliation: Department of Biology, University of Turku, FIN-20014 Turku, Finland. hantuo@utu.fi
authors.forename: Hanna
authors.initials: H
authors.lastname: Tuomisto
authors.forename: Kalle
authors.initials: K
authors.lastname: Ruokolainen
authors.forename: Markku
authors.initials: M
authors.lastname: Yli-Halla
mesh_terms: D003105:Colombia; D017753:Ecosystem; D004484:Ecuador; D004777:Environment; D029624:Ferns / Q000145:classification / Q000254:growth & development; D005843:Geography; D035322:Melastomataceae / Q000145:classification / Q000254:growth & development; D010568:Peru; D012621:Seasons; D012987:Soil; D014197:Trees
chemical_list: D012987:Soil