The 21 focal tree plots were repeatedly clustered into 2–5
groups using a Sørensen distance measurement and flexible beta
linkage (b = 0.25) on tree abundance data without the focal D.
oliveri tree (McCune and Mefford, 1999). Indicator Species Analysis
(Dufreˆne and Legendre, 1997) was applied to determine indicator
species for the different groups. Differences in species composition
between groups were tested with multiresponse permutation
procedures (MRPP) tests with the Sørensen distance measure and a
natural group weighing factor ni/Pni (where ni is the number of
sample plots in each group).