Titouan Dubo , Ignacio Palomo, Aude Zingraff-Hamed , Enora Bruley, Guillaume Collain, Sandra Lavorel

Transformative adaptation is essential to face the unprecedented biodiversity and climate change crises. Nature-based Solutions (NbS) could accelerate the transformation of social-ecological systems to address climate change and biodiversity and Nature’s Contribution to People (NCP) loss. However, they are not widely implemented. Understanding the drivers of decision-making context that support NbS implementation is crucial to address potential bottlenecks and barriers. Here, we conducted semi-structured interviews with managers of twenty NbS implemented in the Alps. We investigated their decision-making contexts using the values-rules-knowledge framework and their transformative characteristics. Using a clustering analysis we identified three types of initiatives sharing similar groups of levers and barriers: the local transformation type implemented self-sufficient initiatives motivated by relational values to nature, supporting the adaptive capacity of nature through informal governance and experiential knowledge sharing; the green deal type implemented gradual change in practices using funding opportunities or regulations to experiment with new approaches fostering instrumental values of nature;  the multi-scale co-production type implemented socially accepted NbS through wide participatory process with local practitioners, and the inclusion of diverse values in initiatives designed to be persistent even when challenged by the instability of funding opportunities. Based on these results we recommend that NbS related policies should: i) foster NbS implementation by local communities who faced economic constraints when implementing new practices; ii) support transdisciplinary programmes to create an inclusive network around NbS practices; and iii) adapt incentives to enable transformative adaptation through NbS. A macro-regional strategy may have the potential to face these challenges.