Constrained indicator species analysis (COINSPAN): An extension of TWINSPAN

A new vegetation classification method, COn-strained-INdicator-SPecies-ANalysis (COINSPAN) is introduced as an elaboration of Two-Way-INdicator-SPecies-ANalysis (TWINSPAN). Instead of operating on the bisection of a primary Correspondence Analysis ordination axis, at each level of division, COINSPAN bisects a primary Canonical Correspondence Analysis axis. The associated computer program, of the same name, performs both analyses as options. COINSPAN is applied to a simple model data set, with two constraining gradients, and to a pine forest vegetation survey in order to illustrate the functioning and utility of the method.