An ordination method that combines gradient analysis and a system of successive approximation. Its chief merit lies in the clarity with which strong floristic gradients are displayed. Applying the method to a series of samples each containing a number of species begins by assigning an arbitrary (e.g. random) number to each species; these numbers are known as species scores. The scores are weighted according to the abundance of each species in each sample, and the weighted average of the species scores in each sample yields a sample score. The weighted average of all the sample scores yields a new species score. The species and sample scores are then standardized by subtracting the means and dividing by the standard deviation. The procedure is repeated until successive iterations produce little or no changes in the values.
Subjects: Plant Sciences and Forestry — Ecology and Conservation.