Managing the impacts of nutrient enrichment on river systems: dealing with complex uncertainties in risk analyses
Article first published online: 6 MAR 2012
© 2012 Blackwell Publishing Ltd
Special Issue: Achieving Ecological Outcomes: Aquatic Ecological Responses to Catchment Management
Volume 57, Issue Supplement s1, pages 108–123, July 2012
How to Cite
PAGE, T., HEATHWAITE, A. L., MOSS, B., REYNOLDS, C., BEVEN, K. J., POPE, L. and WILLOWS, R. (2012), Managing the impacts of nutrient enrichment on river systems: dealing with complex uncertainties in risk analyses. Freshwater Biology, 57: 108–123. doi: 10.1111/j.1365-2427.2012.02756.x
- Issue published online: 21 JUN 2012
- Article first published online: 6 MAR 2012
- (Manuscript accepted 23 January 2012)
- ecological status;
- Water Framework Directive
1. Rivers and their catchments are complex, dynamic and non-equilibrium systems. Although the general functioning of these ecosystems is familiar, the characteristics of particular sites are often poorly known and accurate prediction of future behaviour to inform management decisions is extremely difficult.
2. Simple relationships between river nutrient concentrations and the health of river ecosystems do not exist. Natural variability and practical and technical constraints reduce our ability to set nutrient targets to protect river ecosystems. Particularly challenging is the use of simple dose–response relationships as regulatory threshold targets, whereby sections of river are classified as either passing or failing to meet good ecological status.
3. Ecologically meaningful frameworks are needed that take account of the epistemic uncertainty associated with our predictions. Such frameworks should have clearly defined goals; be holistic; allow for natural variability; help to define ecologically acceptable environmental regimes; recognise that significant uncertainties mean that we will often be using indices rather than absolute measures; and use measures that explicitly include uncertainty estimates. Such approaches allow those outside the decision-making process to understand the level of environmental precaution included in the management of complex systems.