Re‐evaluation of numerical classification methods for delimiting biofacies and biotopes in an estuarine environment

Abstract

Zenetos, A. 1991 01 15: Re-evaluation of numerical classification methods for delimiting biofacies and biotopes in an estuarine environment. Lethaia. Vol. 24. pp. 13–26. Oslo. ISSN 0024–1164. To test the applicability of numerical classificatory methods in defining biotopes and biofacies, several sets of data were combined using alternative measures of similarity and clustering techniques. In both types of analysis (biofacies and biotopes), results showed that binary data contain enough information and can give as good a picture as the quantitative data, provided [hat the appropriate techniques are used. Despite the inadequacy of the living mollusc data. biotope patterns produced by living and subfossil molluscs are similar, suggesting negligible post-mortem transportation and burial of the fauna in its place of occurrence. The biotopes delineated in this study are consistent with Eastwood's (1977) ‘textural facies’ patterns based on the sediment size distribution. In this line, it is suggested that the grain size of the substrate is the main factor determining the distribution of molluscs in the Eden estuary. Moreover. the fact that the same cluster analysis combination (D-coef./Ward's clustering) based on independent variables (fauna and sediment size distribution) led to similar results. emphasizes the objectivity of the methods used and the stability of the clusters generated. Mollusca. numerical taxonomy. biotopes. biofacies. Eden estuary.