asim6: Resampling with total species richness fixed

In irhoppe/cooccur: Abundance Matrix Randomizations

Description

Randomizes an abundance matrix by randomly assigning individuals to matrix cells with probabilities proportional to observed row and column abundance totals until total species richness is reached.

Usage

asim6(speciesData)

Arguments

speciesData

species-by-site abundance matrix

Details

Resamples total abundance conditional on marginal sums and constrained to observed species richness; equivalent to algorithm IR in Ulrich and Gotelli (2010), and to the Fortran subroutine ir in Ulrich (2008).

Value

shuffled abundance matrix

Caution

May generate matrices with empty columns (sites).

References

Ulrich, W. 2008. Program Co-Occurrence. Version 1.

Ulrich, W. and Gotelli, N.J. 2010. Null model analysis of species associations using abundance data. Ecology 91:3384-3397.

See Also

Other abundance matrix null models: asim10_f(), asim10(), asim11_f(), asim11(), asim12_f(), asim12(), asim13_f(), asim13(), asim14_f(), asim14(), asim1_f(), asim1(), asim2_f(), asim2(), asim3_f(), asim3(), asim4_f(), asim4(), asim5_f(), asim5(), asim6_f(), asim7_f(), asim7(), asim8_f(), asim8(), asim9_f(), asim9()

Examples

amat <- rmat(20,12) # creates a random 20 x 12 abundance matrix
asim6(amat)         # performs proportional abundance resampling algorithm

irhoppe/cooccur documentation built on Jan. 1, 2021, 4:23 a.m.