Fashioning river futures: The use of evolutionary trajectories to assess what is realistically achievable (11622)
The ‘shifting baseline syndrome’ asserts that what we measure against in environmental assessments is dependent upon the condition/state of ecosystems at a particular timeframe of reference. Although initially conceived in relation to measures of biodiversity, here we show how this concept can be used to frame shifting terms of reference that define geomorphic constraints upon what is realistically achievable in river rehabilitation. We contrast applications of shifting baselines in relation to two approaches to shaping river futures. First, re-restoration is viewed as an extension of engineering-based command and control perspectives that strive to ‘fix’ a river in place by locking it into a particular image based upon historical reference conditions. Second, ecosystem approaches to river rehabilitation use understandings of evolutionary trajectories to determine and work towards the best achievable condition for any given river system, allowing the river to self-heal whenever possible. We explore the use of the river evolution diagram (developed as part of the River Styles framework) as an approach to scope prospective river futures. Implications for monitoring and adaptive management are highlighted.