Effects of management and climate change in rivers
Biological monitoring often reveals that the 'good ecological status' is not met, thus, further action is required being required. These management actions comprise mitigation, rehabilitation and restoration. Degraded water bodies are being, for instance, restored to improve habitat quality and to support the recovery of biota to meet the quality targets. Monitoring of recent restoration projects in European rivers, however, revealed that the aquatic communities often do not show the anticipated and desired effects of recovery. The objective of WP5.1 is, therefore, to investigate the effects of degradation and restoration on riverine plant and animal communities. The linkages are identified, conceptualised and eventually tested with existing data on river restoration. The results assist statistical modelling of the response of riverine biota to river basin management, whereas the potential impact of global and climate change on degradation and recovery will be included. In particular, WP5.1 aims:
- to gather existing data from previous EC-funded and national projects on the assessment and mitigation of hydromorphological degradation,
- to develop cause-effect-chains linking management measures to biotic responses for a variety of aquatic ecosystem types, restoration measures and organism groups,
- to develop or apply statistical models to predict the response of BQEs to pressure reduction and finally the conditions required to reach good ecological status (includes considering the potential recolonisation of restored sites in catchments with different densities of source populations), and
- to describe best-practice measures of pressure reduction (e.g. restoration measures) and management options to improve the ecological quality of rivers.
A specific workpackage database on river data has been set up, comprising data from 2,500 samples taken at 1,700 stations in 10 European countries. Altogether, four BQEs (fish, benthic invertebrates, macrophytes, benthic diatoms) are covered, while data on all BQEs is available for 250 stations. Environmental data comprise 13 physico-chemical and 16 hydromorphological, together with some catchment and riparian buffer land use classifications. All data have been made available to the Central WISER database to assist data flow to Module 6 on integration of BQEs, habitats and water categories.
Outcome and products
The first outcome of WP5.1 is a deliverable on "Conceptual Models and effects of river rehabilitation and restoration measures on aquatic organisms" (D5.1-1). The report presents a general conceptual framework to summarize and help structure the current knowledge on the effectiveness of river restoration measures and its impacts on the in-stream plant and animal communities. The Conceptual Models are used to illustrate the relationships between three common restoration measures (riparian buffer instalment, instream mesohabitat improvement, weir-removal), its effects on instream environmental key variables, and eventually the impact of changing variables on benthic algae, macrophytes, benthic invertebrates and fish. The three Conceptual Models illustrate well-known cause-effect chains for restoration, but also knowledge gaps based on the peer-reviewed scientific literature and amended by selected reports from the grey literature. (Deliverable D5.1-1)
Relevance for end users
Altogether four end users have been involved in this workpackage to represent the classical groups of end users addressed: River Basin and Water Resources Managers. For both restoration and global/climate change are of vital interest to render River Basin Management effective and successful. The end users have been invited to a Workshop on Conceptual modelling in order to discuss the approach with respect to is practical usefulness and application (see Newsletter No. 2, Wageningen Workshop). Overall, Workpackage 5.1 will provide guidance and best practice management measures for river restoration and management.