PERMDISP tests of homogeneity of dispersions (taxonomic similarity) results based on mean distance to group centroid for all groups within each factor, using log(x+1) transformed species density data.

P-values obtained from permutations of residuals. Significant results indicate spatial taxonomic homogenization in relation to particular factors. In addition, Kruskal-Wallis one-way analysis of variance of median group ASI for each factor. Statistically significant results reject the null hypothesis of no difference between median group ASI.