Strong seasonal associations were present in the benthic community. Statistical comparison of surveys conducted three to nine months apart (Tables 18.7 and 18.8) resulted in correlation coefficients that ranged from 0.47 to 0.75 for normal analyses and from 0.68 to 0.85 for inverse analyses. These are fairly high, but not exceptional, values for large independent data sets. In a pattern that will be repeated in other analyses, the correlation coefficients are slightly lower when functional groups instead of species were used as descriptors for normal analyses. This reflects some loss of information about spatial relationships when combining species into a group. Conversely, functional groups produced slightly higher correlation coefficients than species for inverse analyses, indicating that the variability of groups of species was less than that of individual species. Despite some differences, the results when using species or functional groups always tended

Table 18.6. Associated functional groups based on UPGMA cluster analysis and MDS ordination

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