Analysis of community attributes of the benthic macrofauna of Frierfjord/Langesundfjord and in a mesocosm experiment

Abstract

Sublittoral macrofauna was sampled along a putative pollution gradient at 6 sites in Frierfjord/Langesundfjord. Norway, during the GEEP Mlorkshop. Data were subjected to a variety of multivariate statistical analyses which discriminate between sites on their faunistic attributes, and univariate measures of community stress were determined. Multivariate analyses produced generally slmilar results. Univariate stress measures in combination ranked the sites in order of increasing disturbance. Measured levels of pollutants in the sediments correlated poorly with the multivariate 2-D configurations and with the univariate measures of disturbance. It was concluded that water depth was the overriding factor controlling community structure, and that this masked any possible effects of pollution. The 3 deepest sites d~splayed the most obvious signs of stress, and this was attributed to seasonal anoxia in the deeper parts of Langesundfjord. In order to establish cause and effect relations between measured levels of pollutants (copper and hydrocarbons) and community responses, boxcores of sublittoral sedlment were subjected to 4 levels of contamination in a mesocosm experiment. Although some of the 'classical' intuitive methods indicated possible con~munity responses, the objective methods largely failed to reveal clear-cut differences in community structure between treatment levels. The relative merits of the 'classical' and objective approaches are discussed.

Macrobenthic mollusc fauna inhabiting <i>Halopteris</i> spp. subtidal fronds in Sao Miguel Island, Azores

“…Transformed species abundance [(n i /100 g ADW) 1/4 ] and Shannon diversity data were used to generate triangular matrices of similarities, using the Bray-Curtis coefficient (Bray Curtis, 1957 fide Gray et al, 1988). Similarity matrices were subjected to clustering and ordination analysis (multidimensional scaling ordination -MDS) (Warwick et al, 1990).…”

Relationships between spatial patterns of benthic assemblages in a mangrove forest using different levels of taxonomic resolution

“…Differences in assemblages of organisms between potentially impacted and control locations are frequently examined using non-metric, multidimensional scaling (nMDS) and analysis of similarities (ANOSIM) on Bray-Curtis measures (Clarke & Green 1988, Gray et al 1988, Clarke 1993, Chapman et al 1995. These techniques have also been used to identify natural disturbances, such as those due to burrowing crabs , to quantify patterns of diversity among habitats (Oliver & Beattie 1996, Underwood & Chapman 1998 and to illustrate large-scale biogeographical patterns (Bustamante & Branch 1996).…”

“…Taxonomic resolution is often determined phylogenetically, for example, fauna are identified to species, genera, families, etc. (Gray et al 1988, Mar Ecol Prog Ser 1990, Warwick 1988). There has been recent interest in the use of ecological attributes, such as trophic level rather than phylogenetic relationsh~ps, to group species (Somerfield & Clarke 1995).…”

A Comparison of some methods for analysing changes in benthic community structure

“…As part of the GEEP/IOC Oslo Workshop on the biological effects of pollutants (Gray et al, 1988), macrobenthos samples were collected at a series of six stations in Frierfjord/ Langesundf jord, station A being the outermost and station G the innermost (station F was not sampled for macrobenthos). Folium & Moe (1988).…”