raref: Estimates the species richness for a given number of sampled individuals on the basis of the corresponding rarefaction curve
Description
raref computes rarefaction curve and interpolates the species richness corresponding to a given density of individuals.
Usage
raref(matrix, dens, nrandom=99)
Arguments
matrix
matrix is a typical species-sample matrix. Rows correspond to samples whereas columns stand for species.
dens
A number corresponding to the density for which a species richness estimation is required. dens must be comprised within the range of the observed density.
nrandom
nrandom is the number of a randomizations used in the bootstrap estimation. Values of nrandom
Value
raref returns a list with two components.
rarA data frame with three columns giving the observed species richness for different sample size and corresponding density of individuals.
SinterpA vector with the term dens and the corresponding interpolated species richness.
References
Gotelli, N., Colwell, R. (2001). Quantifying biodiversity: procedures and pitfalls in the
measurement and comparison of species richness. Ecology Letters 4, 379-391.