Intergration (module 6)
Module 6 is addressing the question how different BQEs and water categories respond to degradation and to rehabilitation.
Ecological assessments frequently use several BQEs collected from a number of systems (lakes, streams, coastal areas) and habitats within these systems (e.g. pelagic and benthic, littoral and profundal or riffles and pools). Two innovative aspects of the WFD are the recognition that aquatic systems are not isolated entities, but are nested within a catchment, and that the use of multiple BQEs may increase our understanding of the effects that humans are having on aquatic resources. The use of complementary indicator variables can strengthen inference-based assessments of human-generated effects as well as help to distinguish the effects of multiple stressors. This latter conjecture implies that different BQEs may respond similarly to some stressors (e.g. high redundancy used to strengthen the inference model) but differently to other stressors (low redundancy, but indicating the presence of other stressors).
To design and implement cost-effective management programmes and to scientifically underpin conceptual models of aquatic ecosystem responses to human-induced changes more knowledge of the response signatures of BQEs is required, as well as an understanding of the uncertainties associated with the use of different BQEs. Moreover, in designing robust monitoring programmes consideration should be given not only to the selection of BQEs to test specific hypotheses of change (i.e. stress- response relationships) but also to the system and the habitat that may provide the most robust measure (high precision/low error) of change.