Abstract

Quantitative community ecology is one of the most challenging branches of modern environmetrics. Community ecologists typically need to analyze the effects of multiple environmental factors on dozens (if not hundreds) of species simultaneously, and statistical errors (both measurement and structural) tend to be large and ill-behaved. It is not surprising, therefore, that community ecologists have employed a variety of multivariate approaches. These approaches have been both endogenous and borrowed from other disciplines. The majority of techniques fall into two main groups: classification and ordination. Classification is the placement of species or sample units into groups, and ordination is the arrangement or ‘ordering’ of species and/or sample units along gradients. In this chapter, I will describe the use and properties of the most widely used ordination methods.