custom header test
pianka_skew(m = matrix(rpois(80, 1), nrow = 10))
Takes a niche utilization matrix returns the skewness of the Pianka pairwise niche overlap index.
A large positive value for skewness implies that there are more species pairs with high than low niche overlap. A large negative value for skewness implies there are more species pairs with low than high niche overlap. The performance of this algorithm has not been thoroughly tested with real data sets.
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.
Winemiller, K.O. and E.R. Pianka. 1990. Organization in natural assemblages of desert lizards and tropical fishes. Ecological Monographs 60: 27-55.
obsSkew<- pianka_skew(m=matrix(rpois(40,0.5),nrow=8))
pianka niche overlap index.