The primary device for presenting the results of an ordination model is the ordination diagram. The contents of an ordination diagram can be used to approximate the response data table, the matrix of distances between individual cases, or the matrix of correlations or dissimilarities between individual response variables. In ordination including predictor variables (either explanatory or supplementary variables), we can use the ordination diagram to approximate, among others, the relationship between the response and the predictor variables. The first two sections in this chapter summarise what we can deduce from ordination diagrams that result from linear and unimodal ordination methods.

Before we discuss the rules for interpreting ordination diagrams, we must stress that the absolute values of scores (i.e. coordinates of objects, such as cases, response and predictor variables) in ordination space do not have, in general, any meaning. When interpreting ordination diagrams, we use relative distances of symbols, relative directions of arrows, or relative ordering of projection points. A detailed description of an ordination diagram created in Canoco 5 can be obtained by the Graph | Describe contents menu command or using the ‘lifebuoy’ button in the toolbar.