Assessing the ecological integrity of rivers:: walking the line among ecological, political and administrative interests*

This article considers the interactions among science, politics, public administration and the general public within the framework of the assessment of biological condition as it pertains to ecological integrity. Strong public concern for environmental protection and health helps to shape policy. The legislative mandate of "maintaining and restoring the ecological integrity of waters'' is both a statement of political will and a commitment. The public administration bears the responsibility for efficient water management under the auspices of maintaining a high quality of environmental health. The increasing complexity of perspectives on environmental topics increases the input of ecological sciences to the administrative process. Ecologists play an essential role in advancing scientific knowledge, developing methods to implement legislative mandates and educating the public (and public officials) about natural processes and interactions, as well as the ecological consequences of human activities. A variety of questions posed at the administration level concerning both pollution and physical impairments can be answered by biological assessment. With emphasis on benthic macroinvertebrates and levels of taxonomic resolution, examples from Austria are provided to show the efforts necessary to maintain scientific accuracy whilst maintaining practicality. Some examples of species-centred and community-based surrogate parameters used in Austria to assess the ecological integrity of rivers are presented (e.g. saprobiological aspects, functional feeding groups, longitudinal zonation analysis).