title: Predicting species diversity in tropical forests.
abstract: A fundamental question in ecology is how many species occur within a given area. Despite the complexity and diversity of different ecosystems, there exists a surprisingly simple, approximate answer: the number of species is proportional to the size of the area raised to some exponent. The exponent often turns out to be roughly 1/4. This power law can be derived from assumptions about the relative abundances of species or from notions of self-similarity. Here we analyze the largest existing data set of location-mapped species: over one million, individually identified trees from five tropical forests on three continents. Although the power law is a reasonable, zeroth-order approximation of our data, we find consistent deviations from it on all spatial scales. Furthermore, tropical forests are not self-similar at areas </=50 hectares. We develop an extended model of the species-area relationship, which enables us to predict large-scale species diversity from small-scale data samples more accurately than any other available method.
authors.affiliation: Institute for Advanced Study and Princeton University, Princeton, NJ 08540, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Plotkin
authors.forename: M D
authors.initials: MD
authors.lastname: Potts
authors.forename: D W
authors.initials: DW
authors.lastname: Yu
authors.forename: S
authors.initials: S
authors.lastname: Bunyavejchewin
authors.forename: R
authors.initials: R
authors.lastname: Condit
authors.forename: R
authors.initials: R
authors.lastname: Foster
authors.forename: S
authors.initials: S
authors.lastname: Hubbell
authors.forename: J
authors.initials: J
authors.lastname: LaFrankie
authors.forename: N
authors.initials: N
authors.lastname: Manokaran
authors.forename: L H
authors.initials: LH
authors.lastname: Seng
authors.forename: R
authors.initials: R
authors.lastname: Sukumar
authors.forename: M A
authors.initials: MA
authors.lastname: Nowak
authors.forename: P S
authors.initials: PS
authors.lastname: Ashton