Fraction of (roughly 16,000) tree species in Amazonia that account for half of all trees

Value 1.4 % of species Range: equivalent to 227 species % of species
Organism Biosphere
Reference ter Steege H et al. Hyperdominance in the Amazonian tree flora. Science. 2013 Oct 18 342(6156):1243092. doi: 10.1126/science.1243092. abstractPubMed ID24136971
Method P.325 2nd paragraph: "The ~6-million-km^2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. [Investigators] estimated the total number of tree species in the Amazon by fitting the mean rank-abundance data to Fisher’s log-series distribution."
Comments Abstract: "The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, [investigators] provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees." P.1243092-1 right column 4th paragraph: "Second, the RAD [rank-abundance distribution] suggests that just 227 (1.4%) of the estimated 16,000 species account for half of all individual trees in Amazonia. [Investigators] refer to these species, all of which have estimated populations of >3.7×10^8 trees, as hyperdominant species (see a list of the 20 most abundant species in Table 1 (BNID 112913) and a full list in appendix S1). These hyperdominant species form the basis of the tree communities in individual plots as well, accounting for a median of 41% of trees (range = 0 to 94%, fig. S9) and 32% of species (range = 0 to 78%) per plot (fig. S9)."
Entered by Uri M
ID 112911