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(80-02) Use of benthic invertebrate community for the anthropic impact assessment in marine coastal environments. Garofalo, E.*,1, Bonollo, C.2, Gilli, L.3, 1 CESI, Segrate, Italy2 Department of Biology, Milan, Italy3 ENVITECH, Novara, Italy ABSTRACT- Environmental stress such as chemical pollution is considered to decrease community diversity and species richness and to increase abundance of opportunist species. Benthic macroinvertebrates are often used for ecological assessment as they are strongly linked to the substrate and are therefore potentially influenced by toxic and persistent pollutants accumulated into the sediments. In marine ecosystems, natural variability (patchiness) in the distribution of benthic organisms can be very high, at least as high as the variability in other sediment-related environmental variables such as particle size. Use of marine macrobenthos for ecological assessment has been widespread, sometimes without taking into account the existence of patchiness when field sampling programmes were planned. An experimental work was planned using a Nested Sampling Design that comprises three spatial scales, and three temporal replications. This design was applied to one potential impacted area and to three control areas. Study site was located in an open coastal area, in the Tyrrhenian Sea (Lazio, Italy) characterized by unvegetated soft sediments and an average depth of 5-10 m. Three field campaigns were carried out in May, July and September 2000. On the whole 12 sediment samples and 144 macroinvertebrates samples were collected; a total of more then 13000 organisms were isolated and classiefied to species level. Chemical analyses, performed on the sediment, confirmed the perturbed status of impacted area, due to higher level of PAHs and PCBs. Various statistical analyses were applied on the whole data set, using different data treatment approaches (univariate indices and multivariate methods). The asimmetrical three factors ANOVA for univariates indices did not revealed significative differences between areas. On the contrary, for multivariate analysis variations within areas were less than differences between areas; however no significative differences were detected between conditions (impacted versus control). Key words: benthic macroinvertebrates, marine environment, multivariate analysis, nested sampling design |
