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(59-02) Effects of chemical stress on populations and communities of aquatic vertebrates and invertebrates. Böhmer, Jürgen*,1, Zenker, Armin1, 1 Institute of Zoology, Garbenstr. 30, Stuttgart, Germany ABSTRACT- Many studies have demonstrated negative effects of chemical stressors on organisms and lower levels of biological integration. These results are important for risk assessment in the aquatic environment. However only very little is known about the consequences of the observed effects on population or even community level and upscaling is only possible to a limited degree. To study such effects we compared population and community measures of fish, amphibians and macroinvertebrates in a variety of surface waters with varying concentrations of chemical stressors like acidity, organic pollutants, aluminium or pesticides. As expected sensitive species disappeared at low levels of stress already. Some species, however, increased their population size despite showing stress effects on suborganismic level. This was observed at medium stress primarily, as frequently encountered in German waters. Further observations include effects on age structure and sex ratio of vertebrates, or changes in guild structure of invertebrates. These changes in population and community structure were dependent on the type of stress but also on the type of water body. Using a water-type-specific approach the analysis of population and community reactions may be helpful for the assessment of surface waters and for water management in general, especially since populations and communities provide time integrated and ecologically relevant information (months to years for macroorganisms). Key words: chemical stress, communities, aquatic organisms, assessment |
