Non-metric multidimensional scaling (NMS) was used to
investigate indirect gradients influencing species distribution.
NMS was run on the tree abundance data using the Sørensen
distance measure, six starting dimensions, 40 iterations, an
instability criterion of 105 and a rotation for maximum variance
(McCune and Mefford, 1999). D. oliveri was omitted from this
dataset because it had an artificial frequency of 1 in the focal tree
plots.