Community Change

The Water Framework Directive (WFD) requires European Member States to assess the Ecological Quality Status (EQS) of their water bodies based on Biological Quality Elements (BQEs). A tool called MarMAT (Marine Macroalgae Assessment Tool) was developed to implement the WFD in Portugal, which assesses the EQS of Portugal's coastal intertidal rocky shores. MarMAT is a multimetric method that is compliant with the European WFD requirement. It is based on the composition (Chlorophyta, Phaeophyceae and Rhodophyta) and abundance (coverage of opportunists) of marine macroalgae. This study focused on the demands of the WFD to have the assessment methodologies legally accepted by the European Commission. The following factors were examined: (a) the response of MarMAT against anthropogenic pressures; (b) the ability of MarMAT to report all of the five quality classes (bad, poor, moderate, good and high); and (c) the performance of MarMAT, specifically in comparing the RSL (Reduced Species List) methodology with the utility of including the abundance (coverage of opportunists) metric and the necessity of locally adapted reference conditions and boundaries. MarMAT was high inversely correlated (p < 0.001) with anthropogenic pressure. MarMAT also successfully reported all of the quality classes (bad to high) and captured the community changes more accurately when using the coverage of opportunists metric. Because MarMAT satisfactorily covered all of the issues examined, MarMAT may be accepted as a compliant assessment methodology in the scope of the WFD requirements.

Trends in benthic macroinvertebrate populations were examined in inner and outer Saginaw Bay, Lake Huron, from 1987 to 1996. These years represent the time period after phosphorus abatement, but immediately before (1987 to 1990) and after (1991 to 1996) colonization of the bay by the zebra mussel, Dreissena polymorpha. In 1987 to 1990, densities of the major macroinvertebrate groups in

The effects of cypermethrin, a commonly used pyrethroid insecticide, were studied in small in situ enclosures situated in an eutrophic lake over an 11-day period. The experimental design used a regression principle that included three untreated controls and a gradient of six unreplicated cypermethrin concentrations, ranging from 0.01 to 6 μg/l. This paper is the second in a series of two and describes the effects on the species composition of the crustacean, rotifer, periphyton and phytoplankton communities. Multivariate ordination technique (redundancy analysis (RDA) combined with Monte Carlo permutation tests) showed that exposure to cypermethrin caused significant changes in the species composition of the communities. Changes in the structure of the communities were observed following exposure to a nominal concentration of 0.13 μg cypermethrin per litre above. The direct acute effect of exposure to cypermethrin was a rapid decrease of many species of crustacean zooplankton. The alterations in crustacean species composition were probably due to variations in susceptibility to the direct toxic effects of cypermethrin. No effects concentration (NEC) for individual zooplankton species were calculated using inverse regression and revealed that copepod nauplii were the most sensitive (NEC=0.01 μg/l) of the crustacean groups examined. The observed alterations of the species composition of the autotrophic communities as well as of the rotifers were most likely caused indirectly by cypermethrin, mediated through the direct negative effects of the insecticide on the crustacean grazers. The results of this experiment provide further knowledge about the direct and indirect effects of pesticide stress on the ecosystem level. They also show that there is a variation in sensitivity between different species of zooplankton under natural conditions and thus exemplify the necessity of multispecies approaches in the risk assessment of pesticides.