Strategies for Restoring River Ecosystems: Sources of Variability and Uncertainty in Natural and Managed Systems

11. Strategies for Restoring Rivers: Problems and Opportunities

P. A. Bisson and R. C. Wissmar

doi: https://doi.org/10.47886/9781888569469.ch11

Abstract.—Development of effective restoration strategies for river systems requires the use of scientific concepts about sources of variability and uncertainty. Most of these concepts are based on physical and biological properties, their processes and variability, and human-induced uncertainties within river drainages and their differences across regions. Important natural properties include climate; hydrology; geology; geomorphology; disturbance regimes like floods and fires; connectivity between river channels and floodplains; plant and animal population and community characteristics; and trophic dynamics. A major question when developing restoration strategies is, “How can we use information about variations in natural properties and anthropogenic actions to assist policy makers by reducing the uncertainty of decisions and to better manage river ecosystems?” We evaluate several concepts of variability in river ecosystems that are presented in this book: spatial and temporal scales, connectivity, and disturbance. Case studies of fish responses to temperature and hydrologic variability are used to show how this information can be applied to restoration plans. We also focus on the need to incorporate concepts of “recovery” into restoration strategies, and present several examples of recovery processes that occur following disturbances and potential restorative actions. Finally, we explore alternatives for evaluating and treating uncertainty in societal and policy arenas.