ISSN:
1573-5052
Keywords:
Bray-Curtis
;
Coenocline
;
Components analysis
;
Non-linear
;
Ordination
;
Polynomial
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Recent studies suggest problems resulting from using essentially linear ordination techniques on non-linear ecological data. A new non-linear method, termed polynomial ordination, was developed in response to these problems. Its effectiveness was compared to that of two standard techniques, Bray-Curtis ordination and principal components analysis, by testing with both simulated and field data. The original species axes are resolved into their principal components. If significant curvilinear relationships between principal components are present, new axes are defined along these curves. The coordinates of positions of the sample points along the axes are then determined. Using simulated data, the coordinates of the sample points on the first axis were compared to their coordinates on the original simulated gradient. Two statistics were used to evaluate how well the gradient was recovered. Of the methods tested, polynomial ordination best placed the samples in the correct order, although principal components analysis better recovered their absolute positions. Ordinations of vegetation samples along a Sonoran Desert bajada by all three methods suggested that soil particle size is a major environmental gradient affecting the species composition of the vegetation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00717647
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