Access

You are not currently logged in.

Access JSTOR through your library or other institution:

login

Log in through your institution.

Journal Article

Canonical Correspondence Analysis: A New Eigenvector Technique for Multivariate Direct Gradient Analysis

Cajo J. F. Ter Braak
Ecology
Vol. 67, No. 5 (Oct., 1986), pp. 1167-1179
Published by: Wiley on behalf of the Ecological Society of America
DOI: 10.2307/1938672
Stable URL: http://www.jstor.org/stable/1938672
Page Count: 13
  • Download ($42.00)
  • Subscribe ($19.50)
  • Add to My Lists
  • Cite this Item
Canonical Correspondence Analysis: A New Eigenvector Technique for Multivariate Direct Gradient Analysis
Preview not available

Abstract

A new multivariate analysis technique, developed to relate community composition to known variation in the environment, is described. The technique is an extension of correspondence analysis (reciprocal averaging), a popular ordination technique that extracts continuous axes of variation from species occurrence or abundance data. Such ordination axes are typically interpreted with the help of external knowledge and data on environmental variables; this two-step approach (ordination followed by environmental gradient identification) is termed indirect gradient analysis. In the new technique, called canonical correspondence analysis, ordination axes are chosen in the light of known environmental variables by imposing the extra restriction that the axes be linear combinations of environmental variables. In this way community variation can be directly related to environmental variation. The environmental variables may be quantitative or nominal. As many axes can be extracted as there are environmental variables. The method of detrending can be incorporated in the technique to remove arch effects. (Detrended) canonical correspondence analysis is an efficient ordination technique when species have bell-shaped response curves or surfaces with respect to environmental gradients, and is therefore more appropriate for analyzing data on community composition and environmental variables than canonical correlation analysis. The new technique leads to an ordination diagram in which points represent species and sites, and vectors represent environmental variables. Such a diagram shows the patterns of variation in community composition that can be explained best by the environmental variables and also visualizes approximately the @'centers@' of the species distributions along each of the environmental variables. Such diagrams effectively summarized relationships between community and environment for data sets on hunting spiders, dyke vegetation, and algae along a pollution gradient.

Page Thumbnails

  • Thumbnail: Page 
1167
    1167
  • Thumbnail: Page 
1168
    1168
  • Thumbnail: Page 
1169
    1169
  • Thumbnail: Page 
1170
    1170
  • Thumbnail: Page 
1171
    1171
  • Thumbnail: Page 
1172
    1172
  • Thumbnail: Page 
1173
    1173
  • Thumbnail: Page 
1174
    1174
  • Thumbnail: Page 
1175
    1175
  • Thumbnail: Page 
1176
    1176
  • Thumbnail: Page 
1177
    1177
  • Thumbnail: Page 
1178
    1178
  • Thumbnail: Page 
1179
    1179
Part of Sustainability