null.breadth

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Description

This function calculates the null expectation of host breadth if herbivores sample diet items randomly.

Usage

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null.breadth(dat, dist.method = "jaccard", rep = 100, quantiles = c(0.025, 0.975), 
scaled = FALSE)

Arguments

dat

A matrix of diet associations. Rows are herbivores and columns are diet items.

dist.method

Dissimilarity index passed on to vegdist in the 'vegan' package.

rep

The number of permutations to generate a null distribution

quantiles

A vector length of two indicating the lower and upper quantiles to report for the null distribution.

scaled

A logical indicating whether to report the scaled ordinated host breadth.

Value

An array show the lower and upper quantiles of the null distribution for each taxonomic richness

Author(s)

James Fordyce

References

Fordyce, J.A., C.C. Nice, C.A. Hamm, & M.L. Forister. Quantifying diet breadth through ordination of host association. Ecology

Examples

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testdata<-	
	c(		
			0,0,0,0,1,0,0,0,0,0,
			0,0,0,0,0,0,1,1,0,0,
			1,1,1,0,0,0,0,0,0,0,
			0,0,0,0,1,1,0,1,0,1,
			1,1,1,0,0,0,1,0,0,0,
			1,1,0,0,1,0,1,0,0,0,
			0,0,0,1,0,0,1,0,1,1,
			1,0,1,0,1,1,0,0,0,1, 
			1,1,0,0,1,0,0,1,1,1,
			1,1,1,0,1,1,0,1,1,1) 


dat<-array(dim=c(10,10),data=testdata)
dat<-t(dat)
colnames(dat)<-paste("",LETTERS[1:10],sep="")
rownames(dat)<-paste("bug",1:10,sep="")

null.breadth(dat)