Journal of the Royal Society of Western Australia, 87(2), June 2004 
forms). Shannon diversity index and evenness index 
(Kent & Coker 1992) were compared using Kruskal - 
Wallis test. Indicator species, defined as those species 
which characterise and differentiate a group, were 
determined for each community using the approach 
outlined by Dufrene & Legendre (1997). For each group 
of sites defined by the classifications, homogeneity (in 
terms of species composition) was calculated using the 
following formula: H=1-RV where H is the homogeneity 
and RV is the relative variance of a particular group and 
was calculated, following the recommendations of 
Pressey & Bedward (1991), using the dissimilarity 
measure used to construct the site X site association 
matrix. Simply, RV for a particular group was calculated 
as the average within-group association (i.e. of all pair¬ 
wise combinations of sites) divided by the average pair¬ 
wise association for the data set as a whole. 
Results 
Classification and descriptions of communities 
The dendrogram resulting from the UPGMA 
classification of sites (Fig 2) was produced by first cutting 
the classification at the 21 group level and then joining 5 
smaller groups (consisting of 1 or 2 sites) to adjacent 
groups in the dendrogram. This produced 16 groups. 
Figure 2. Partial dendrogram of the UPGMA classification of sites showing relationships between the 16 plant communities, 8 subtypes 
and 2 broad vegetation types. (N.B. The full dendrogram was originally cut at the 21 group level. Following fusion of adjacent groups, 
this number was reduced to 16. The positions of the original splits are shown on the dendrogram using arrows). 
66 
