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Community Analysis Package

16

Divisive cluster analysis

In divisive methods the samples (columns) all start as members of single group

which is subsequently subdivided. TWINSPAN is an example of such an

approach. The method available under Clustering|Divisive minimises the sums of

squares of the dissimilarity of each group formed.  When selected you must

specify the number of groups required. Thus, this method is best used when

some other method such as TWINSPAN or PCA has suggested the presence of a

number of groups and you wish to see if an independent method can produce the

same group membership.

To print this output use File | Print.

The plot clusters tab presents a plot of the position of the samples (quadrates) in

space as defined by the abundance of two species present. Besides each sample

is a number that identifies the cluster into which the sample has been assigned.

The particular species used to define the position of the samples can be selected

using the two drop down menus at the base of the graph.

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