title: Continental-scale patterns of canopy tree composition and function across Amazonia.
abstract: The world's greatest terrestrial stores of biodiversity and carbon are found in the forests of northern South America, where large-scale biogeographic patterns and processes have recently begun to be described. Seven of the nine countries with territory in the Amazon basin and the Guiana shield have carried out large-scale forest inventories, but such massive data sets have been little exploited by tropical plant ecologists. Although forest inventories often lack the species-level identifications favoured by tropical plant ecologists, their consistency of measurement and vast spatial coverage make them ideally suited for numerical analyses at large scales, and a valuable resource to describe the still poorly understood spatial variation of biomass, diversity, community composition and forest functioning across the South American tropics. Here we show, by using the seven forest inventories complemented with trait and inventory data collected elsewhere, two dominant gradients in tree composition and function across the Amazon, one paralleling a major gradient in soil fertility and the other paralleling a gradient in dry season length. The data set also indicates that the dominance of Fabaceae in the Guiana shield is not necessarily the result of root adaptations to poor soils (nodulation or ectomycorrhizal associations) but perhaps also the result of their remarkably high seed mass there as a potential adaptation to low rates of disturbance.
authors.affiliation: Institute of Environmental Biology, Section Plant Ecology and Biodiversity, and the National Herbarium of the Netherlands NHN, Utrecht University branch, Sorbonnelaan 14-16, 3584 CA Utrecht, The Netherlands. h.tersteege@bio.uu.nl
authors.forename: Hans
authors.initials: H
authors.lastname: ter Steege
authors.forename: Nigel C A
authors.initials: NC
authors.lastname: Pitman
authors.forename: Oliver L
authors.initials: OL
authors.lastname: Phillips
authors.forename: Jerome
authors.initials: J
authors.lastname: Chave
authors.forename: Daniel
authors.initials: D
authors.lastname: Sabatier
authors.forename: Alvaro
authors.initials: A
authors.lastname: Duque
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Molino
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Prévost
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Spichiger
authors.forename: Hernán
authors.initials: H
authors.lastname: Castellanos
authors.forename: Patricio
authors.initials: P
authors.lastname: von Hildebrand
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Vásquez
mesh_terms: D044822:Biodiversity; D018533:Biomass; D017753:Ecosystem; D011157:Population Dynamics; D011891:Rain; D012621:Seasons; D013020:South America; D014197:Trees / Q000145:classification* / Q000502:physiology*; D014329:Tropical Climate