Classification and ordination in the Indian Peaks area,Colorado Rocky Mountains

Summary A mid-latitude, Northern Hemisphere alpine vegetation in the Colorado Rocky Mountains was suitable for analysis by syntaxonemie and numerical methods, which interpreted the Braun-Bianquet association data, distributed by habitat and vegetation dominance types, correspondingly. Classification and ordination yielded complementary, interpretable results, which combined were more informative than results of either technique alone. Syntaxonomic results can faeilitate the interpretation of numerical results; the syntaxonomic relationships can be clarified by the results of numerical analysis.Alliances and orders of the Braun-Blanquet hierarchy, and their diagnostic taxa groups were derived by numerical methods from an association/taxa matrix. On the basis of this matrix, numerical methods demonstrated some of the environmental gradient complexes controlling the compositional variation. The compositional distinctiveness and uniformity of orders and alliances parallel environmental distictiveness and uniformity.The following attributes of the sampled vegetation and environment were probably responsible for the successful combination of syntaxonomic and numerical results: 1. The sampled area as a geographically limited universe, characterized by relative environmental, biotic, and historical distinctiveness and uniformity, 2. The wide range, high diversity, and clear denfinition of habitat and vegetation dominance types. Because it effectively summarizes and simplifies field data, syntaxonomy can play an important role in building local vegetatio models.Most of the figures in this paper are from a book version of a University of Colorado, Department of Environmental, Population, and Organismic Biology, Ph. D. thesis which was produced at the Institute of Arctic and Alpine Research. I would like to thank Dr. P.J. Webber, the thesis advisor, for his support, for suggesting the numerical methods, and for computer programs which were written by W.F. Reid. Vicki Dow, Marilyn Joel, and Karen Sproul drafted the majority of figures. I am grateful to Gwen Archer for editorial help.