An Application of Non-Metric Multidimensional Scaling to the Construction of an Improved Species Plexus

(1) A technique of non-metric multidimensional scaling has been applied to the problem of constructing an objective species plexus, using data for the fifty most frequently occurring vascular plant species in front of the Storbreen glacier, Jotunheimen, Norway. (2) The technique, designed to represent a set of points in a space defined by a small number of dimensions, is used to reduce a matrix of similarities between species to a two-dimensional configuration. The configuration, in which a known and low amount of distortion has been minimized, is used as the basis for plexus definition. (3) Within the plexus three loose groupings of species have been detected, which, together with much finer detail, are interpreted with reference to mapped distributions of single species within the study area, and are related to successional status and to environmental tolerance. (4) Results from the use of four different quadrat sizes substantiate the plexus structure, which is contrasted with a representation based on principal components analysis.