hull.sad {BAT}

Species-abundance distribution (SAD) using convex hulls.

Description

Fits the SAD to community abundance data using convex hulls.

Usage

hull.sad(comm, octaves = TRUE, scale = FALSE, raref = 0, runs = 100)

Arguments

comm

A 'convhulln' object or list, preferably built with function hull.build.

octaves

a boolean indicating whether octaves should be calculated.

scale

scale y-axis to sum 1.

raref

An integer specifying the number of individuals for rarefaction (individual based). If raref < 1 no rarefaction is made. If raref = 1 rarefaction is made by the minimum abundance among all sites. If raref > 1 rarefaction is made by the abundance indicated. If not specified, default is 0.

runs

Number of resampling runs for rarefaction. If not specified, default is 100.

Details

The Species Abundance Distribution describes the commonness and rarity in ecological systems. It was recently expanded to accomodate phylegenetic and functional differences between species (Matthews et al., subm.). Classes defined as n = 1, 2-3, 4-7, 8-15, .... Rarefaction allows comparison of sites with different total abundances.

Value

A vector or matrix with the different values per class per community.

References

Matthews et al. (subm.) Phylogenetic and functional dimensions of the species abundance distribution.

Examples

comm = rbind(c(1,3,0,5,3), c(3,2,5,1,0))
colnames(comm) = c("SpA", "SpB", "SpC", "SpD", "SpE")
rownames(comm) = c("Site 1", "Site 2")

trait = data.frame(body = c(1,2,3,4,4), beak = c(1,5,4,1,2))
rownames(trait) = colnames(comm)

hv = hull.build(comm, trait)
hull.sad(hv, scale = TRUE)
hull.sad(hv, octaves = FALSE)
hull.sad(hv, raref = TRUE)