Reimagining large river management using the Resist-Accept-Direct(RAD)framework in the Upper Mississippi River

Background Large-river decision-makers are charged with maintaining diverse ecosystem services through unprec-edented social-ecological transformations as climate change and other global stressors intensify.The interconnected,dendritic habitats of rivers,which often demarcate jurisdictional boundaries,generate complex management chal-lenges.Here,we explore how the Resist–Accept–Direct(RAD)framework may enhance large-river management by promoting coordinated and deliberate responses to social-ecological trajectories of change.The RAD frame-work identifies the full decision space of potential management approaches,wherein managers may resist change to maintain historical conditions,accept change toward different conditions,or direct change to a specified future with novel conditions.In the Upper Mississippi River System,managers are facing social-ecological transformations from more frequent and extreme high-water events.We illustrate how RAD-informed basin-,reach-,and site-scale decisions could:(1)provide cross-spatial scale framing;(2)open the entire decision space of potential management approaches;and(3)enhance coordinated inter-jurisdictional management in response to the trajectory of the Upper Mississippi River hydrograph.Results The RAD framework helps identify plausible long-term trajectories in different reaches(or subbasins)of the river and how the associated social-ecological transformations could be managed by altering site-scale conditions.Strategic reach-scale objectives may reprioritize how,where,and when site conditions could be altered to contribute to the basin goal,given the basin’s plausible trajectories of change(e.g.,by coordinating action across sites to alter habitat connectivity,diversity,and redundancy in the river mosaic).Conclusions When faced with long-term systemic transformations(e.g.,>50 years),the RAD framework helps explicitly consider whether or when the basin vision or goals may no longer be achievable,and direct options may open yet unconsidered potential for the basin.Embedding the RAD framework in hierarchical decision-making clarifies that the selection of actions in space and time should be derived from basin-wide goals and reach-scale objectives to ensure that site-scale actions contribute effectively to the larger river habitat mosaic.Embedding the RAD framework in large-river decisions can provide the necessary conduit to link flexibility and innovation at the site scale with stability at larger scales for adaptive governance of changing social-ecological systems.

Bright spots for inland fish and fisheries to guide future hydropower development

Hydropower production is one of the greatest threats to fluvial ecosystems and freshwater biodiversity.Now that we have entered the Anthropocene,there is an opportunity to reflect on what might constitute a‘sustainable’Anthropocene in the context of hydropower and riverine fish populations.Considering elements of existing practices that promote favorable social-ecological outcomes(i.e.,‘bright spots’)is timely given that there are plans to expand hydropower capacity in previously undammed rivers,intensify dam development in some of the world's largest river systems,and re-license existing facilities.We approach this from a pragmatic perspective:for the foreseeable future,hydropower will likely remain an important source of renewable electricity.To offer support for moving toward a more‘sustainable’Anthropocene,we provide syntheses of best practices during the siting,design,construction,operation,and compensation phases of hydropower development to minimize impacts on inland fish.For each phase,we offer positive examples(or what might be considered‘bright spots’)pertaining to some of the approaches described within our syntheses,acknowledging that these projects may not be viewed as without ecological and(or)societal detriment by all stakeholders.Our findings underscore the importance of protecting critical habitat and free-flowing river reaches through careful site selection and basinscale planning,infrastructure designs that minimize reservoir effects and facilitate safe passage of fish,construction of hydropower plants using best practices that minimize long-term damage,operating guidelines that mimic natural flow conditions,and compensation that is lasting,effective,inclusive,and locally relevant.Learning from these‘bright spots’may require engagement of diverse stakeholders,professionals,and governments at scales that extend well beyond a given site,river,or even basin.Indeed,environmental planning that integrates hydropower development into broader discussions of conserving regional biodiversity and ecosystem services will be of utmost importance.