The term “environmental flows” describes the quantities, quality, and patterns of water flows required to sustain freshwater and estuarine ecosystems and the ecosystem services they provide. Environmental flows may be achieved in a number of different ways, most of which are based on either (1) limiting alterations from the natural flow baseline to maintain biodiversity and ecological integrity or (2) designing flow regimes to achieve specific ecological and ecosystem service outcomes. We argue that the former practice is more applicable to natural and semi‐natural rivers where the primary objective and opportunity is ecological conservation. The latter “designer” approach is better suited to modified and managed rivers where return to natural conditions is no longer feasible and the objective is to maximize natural capital as well as support economic growth, recreation, or cultural history. This permits elements of ecosystem design and adaptation to environmental change. In a future characterized by altered climates and intensive regulation, where hybrid and novel aquatic ecosystems predominate, the designer approach may be the only feasible option. This conclusion stems from a lack of natural ecosystems from which to draw analogs and the need to support broader socioeconomic benefits and valuable configurations of natural and social capital.

Responding to global change represents an unprecedented challenge for society. Decision makers tend to address this challenge by framing adaptation as a decision problem, whereby the responses to impacts of change are addressed within existing decision processes centred on defining the decision problem and selecting options. However, this ‘decision-making perspective’ is constrained by societal values and principles, regulations and norms and the state of knowledge. It is therefore unsuitable for addressing complex, contested, cross-scale problems. In this paper we argue that simply broadening the decision-making perspective to account for institutions and values is not enough. We contend the decision-making perspective needs to be connected with a broader ‘decision-context perspective’ that focuses on how the societal system of decision processes affects the manner in which a particular problem is addressed. We describe the decision context as an interconnected system of values, rules and knowledge (vrk). The interaction of systems of vrk both creates and limits the set of practical, permissible decisions; the types of values, rules and knowledge that influence the decision and the capacity for change and transformation in the decision context. We developed a framework to analyse the interactions between values, rules and knowledge and their influence on decision making and decision contexts of adaptation initiatives, and applied it retrospectively to three projects on adaptation to sea-level rise. Our analysis revealed: (1) specific examples of how interactions between vrk systems constrained existing framings of decision making and the development of options for coastal adaptation; (2) limitations in the adaptive management strategies that underpinned the projects and (3) how the linked systems of vrk can allow adaptation practitioners to structure adaptation as a process of co-evolutionary change that enables a broader set of social issues and change processes to be considered. Adaptation projects that focus on the decision context represent a pragmatic alternative to existing decision-focused adaptation. By using the vrk model to diagnose constraints in decision processes, we show how the reframing of adaptation initiatives can reveal new approaches to developing adaptation responses to complex global change problems

International audienceTransformative adaptation will be increasingly important to effectively address the impacts of climate change and other global drivers on social-ecological systems. Enabling transformative adaptation requires new ways to evaluate and adaptively manage trade-offs between maintaining desirable aspects of current social-ecological systems and adapting to major biophysical changes to those systems. We outline such an approach, based on three elements developed by the Transformative Adaptation Research Alliance (TARA): (1) the benefits of adaptation services; that subset of ecosystem services that help people adapt to environmental change; (2) The values-rules-knowledge perspective (vrk) for identifying those aspects of societal decision-making contexts that enable or constrain adaptation and (3) the adaptation pathways approach for implementing adaptation, that builds on and integrates adaptation services and the vrk perspective. Together, these elements provide a future-oriented approach to evaluation and use of ecosystem services, a dynamic, grounded understanding of governance and decision-making and a logical, sequential approach that connects decisions over time. The TARA approach represents a means for achieving changes in institutions and governance needed to support transformative adaptation