Objective methods for the classification of vegetation. II. Fidelity and indicator value

Abstract

A new index of fidelity is described, based on the ratio of frequencies for the species in two communities. The importance of significance tests in determining characteristic species is emphasized.

The value of a species as indicator of a particular community is taken as the ratio of the frequency in that community to the frequency elsewhere within the area studied. An index to express this is proposed.

The value of discriminant functions in enabling vegetation samples of uncertain affinities to be allotted to one of several possible communities is demonstrated. An example is given in which this technique has been used to determine whether one community can be regarded as intermediate between two others, or has special features of its own.

The paper is illustrated by data taken from publications of the Zurich-Montpellier school, and by original data collected in the Victorian Mallee.