Stewardship innovation: the forgotten component in maximising the value of urban nature-based solutions

Nature-based solutions (NBS) enable the ecosystem service benefits associated with natural landscapes to be embedded into the built environment, simultaneously providing environmental, social, and economic benefits. This represents a mechanism for renaturing cities that can address many of the interrelated challenges associated with urbanisation and climate change. If NBS can be delivered effectively on citywide scales, it presents an opportunity for the development of sustainable, resilient, and liveable cities. Examples of innovation in relation to planning and delivering NBS are emerging globally. However, the stewardship plan, an essential element of NBS that typically underpins the long-term success of these high-profile initiatives, is often overlooked or under-planned. Careful consideration of the technical, financing, and governance aspects of NBS stewardship can be critical to determining whether an NBS is able to deliver the multifunctional benefits for which it was designed, adapt to changing needs and environmental conditions, and avoid becoming a liability to those communities it was designed to benefit. Here we present a series of case studies demonstrating how innovation in NBS stewardship can secure and maximise the long-term success of NBS and avoid the legacy of neglected or poorly managed green wash.