Fixed number subsampler

ssN {sub.sample}

Usage

ssN(x, N, spp.names = NULL)

Arguments

`x`	a data frame or a matrix with samples in columns and taxa in rows
`N`	Number of individuals to be in subsamples
`spp.names`	if x is a data frame, it is assumed that the row names will be species names. Otherwise they can be supplied separately as a vector of the same length as the number of rows in x. If x is not a data frame and spp.names = NULL, they will be reported as numbers.

Details

This function randomly selects N individuals from each sample and returns a matrix of subsampled species counts in the same format as x. If N is less than the total number of individuals in a sample, the full sample is returned

Value

ss.x

a data frame of the same structure of x, but with subsampled counts

Author(s)

Chris Walsh: Chris.Walsh@sci.monash.edu.au.

References

Marchant, R. (1989) A subsampler for samples of benthic invertebrates. Bulletin of the Australian Society for Limnology 12, 49-52.

Examples

#subsamples of 100 individuals from a set of invertebrate #samples urban <- read.table("urban.txt", header=TRUE) urban.100 <- ssN(urban[,2:24],100,spp.names = urban[,1]) urban.100

Urban Water Ecology