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A generalized standardization procedure in ecological ordination: Tests with Principal Components Analysis
Author(s) -
Karadži Branko,
Popovi Ranka
Publication year - 1994
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3236158
Subject(s) - ordination , standardization , principal component analysis , sample (material) , ecology , gradient analysis , vegetation (pathology) , principal (computer security) , field (mathematics) , mathematics , statistics , data mining , computer science , econometrics , biology , pure mathematics , medicine , chemistry , chromatography , pathology , operating system
. Standardization by norms of sample position vectors as well as by sample totals has been used frequently in vegetation ecology. Both standardizations are only special cases of the Generalized Standardization Procedure (GSP) described in this paper. The general procedure allows a wide choice of data transformations simply by varying values of a single standardization parameter. Principal Components Analysis (PCA) often involutes opposite ends of a coenospace, producing results that may be difficult to interpret. Experiments with simulated as well as field data sets revealed that involuted gradients can be unfolded if GSP is applied prior to PCA. Compared to Correspondence Analysis, GSP‐PCA was superior in recovering the structure of analysed coenoclines.