RELATING BENTHIC INFAUNAL COMMUNITY STRUCTURE TO ENVIRONMENTAL VARIABLES IN ESTUARIES USING NONMETRIC MULTIDIMENSIONAL-SCALING AND SIMILARITY ANALYSIS

In 1994, 19 stations were sampled (2 replicates/station) with Young gr abs in association with the EMAP-Estuaries Carolinian Province Base Mo nitoring in Florida. A total of 295 unique benthic infauna taxa and 96 47 individuals were identified and enumerated. Environmental data (bot tom-water quality, sediment grain size, sediment metals, and organics) and benthic community data were analyzed using hierarchical agglomera tive cluster analysis and ordination via nonmetric multidimensional sc aling. Bray-Curtis similarities and Euclidean distance were used as th e distance measures for biotic and abiotic data, respectively. Multiva riate analyses were complemented by examining incremental contribution s of benthic taxa to similarity values using a percentage similarity t echnique. A low-salinity site in a tributary to the St. Johns River ha d benthic communities uniquely different from those of moderate-to hig h-salinity sites. A diverse assemblage of polychaetes, gastropods, biv alves, amphipods, sipunculans, and phoronids was consistently associat ed with relatively unimpacted sites in the Indian River Lagoon. Infaun al community structure in the northern portion of the study area was i nfluenced by the nearby Atlantic Ocean. Community shifts in associatio n with latitudinal gradients and concentrations of sediment metals and organics were apparent. The nonparametric multivariate techniques use d in this study were particularly effective at delineating and definin g fine-scale community differences.