Assessing the progress of river restoration in the UK: has ecological condition improved over two decades of intervention?

Abstract

Context: Habitat condition indicates the immediate success of efforts to revegetate degraded river basins as well as longer-term progress towards improving water quality. In the context of the Water Framework Directive, habitat condition in the UK also reflects how well international environmental policy translates into improved river management domestically. Objectives: 1. To assess whether habitat condition in the UK has improved or declined over the past two decades, 2. To assess whether regions identified by the first WFD assessment have improved or declined. Methods: Statistical and spatial analysis of more than 25,000 habitat condition records collated in the River Habitat Survey over the 1990s and 2000s. Computation of an Index of Change demonstrating the improvement or decline of habitat quality in Local Authorities. Comparison of Indices of Change with a sub-sample of 1,727 WFD assessments conducted in 258 Local Authorities. Results: Measures indicate that habitat quality has declined. Riparian quality has improved. 27 regions were identified with the worst declining quality. Condition has declined most substantially in regions that were previously in ‘good’ condition. Conclusion: Priorities for future investment should include improving degraded sites, protecting high quality sites, and increasing monitoring of ‘data poor’ regions. We offer a framework for decision making, including distinguishing the underlying cause of quality decline. Habitat quality decline in the UK mirrors the experience of European nations and points to systemic challenges associated with implementing international water policy in a national context.