Interdisciplinary solutions to enable nature-based solutions for coastal protection achieve ecological and engineering outcomes

Nature-based solutions (NbS) present a promising approach to coastal protection, leveraging the natural capacity of coastal ecosystems to mitigate hazards. Despite their potential, the practical implementation of NbS faces obstacles, including a lack of clear guidance for design and implementation. In this study, we conducted interviews with 34 practitioners involved in NbS projects for coastal protection to (1) identify key perceived barriers and suggested/or realised solutions and (2) assess how these varied among practitioner groups, spanning Coastal Engineers, Coastal Engineering Scientists, Ecologists, and/or Project Managers. During the interviews, practitioners identified 34 distinct challenges to NbS implementation, falling into 14 categories and 345 solutions into 15 categories. Both challenges and solutions varied between practitioner groups. While all groups identified unfamiliarity with NbS as a key challenge, Coastal Engineers and Coastal Engineering Scientists had more design-focused views about NbS challenges (e.g. risk, technical guidelines and data deficits) and solutions (e.g. hybrid solutions). In contrast, Ecologists and Project Managers typically had more implementation-focused challenges (e.g. cost/lack of funding) and opportunity-driven solutions (e.g. community acceptance and education). The solutions most suggested by Coastal Engineers were for hybrid solutions, whereas Coastal Engineering Scientists suggested interdisciplinary teams. The anthropocentric-ecocentric gap between engineers and ecologists highlights the need for NbS teams to be interdisciplinary and utilise standardised language. Overcoming challenges to NbS will also require advocacy for government support and policy reform, along with early, meaningful engagement and capacity building with Indigenous people, which was identified as a crucial solution to current NbS challenges.