RA3 Niche Overlap Randomization Algorithm

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Description

Randomizes a numeric utilization matrix speciesData by reshuffling the elements within each row.

Usage

1
ra3(speciesData = matrix(rpois(80, 1), nrow = 10))

Arguments

speciesData

a resource utilization matrix (rows = species, columns = discrete resource states) filled with non-negative real numbers.

Details

The resource utilization matrix (rows = species, columns = discrete resource categories) may include zeroes, but no negative numbers or missing values. Relative resource within a species is first calculated, so the rows need not sum to 1.0.

Value

Returns a random utilization matrix with the same dimensions as the input matrix.

Note

This algorithm retains the niche breadth and zero states for each species, but randomizes the assignment of each utilization value to a different niche category. It performs effectively in simulation studies and is recommended for analysis of niche overlap patterns.

References

Winemiller, K.O. and E.R. Pianka. 1990. Organization in natural assemblages of desert lizards and tropical fishes. Ecological Monographs 60: 27-55.

Examples

1
ranUtil <- ra3(speciesData=matrix(rpois(40,0.5),nrow=8))

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