Governing Multifunctional and Biodiverse NbS in a Changing Climate: The Case of Switzerland’s Protection Forests

Around 50 % of forests in Switzerland are classified as “protection forests”, serving as nature-based solutions (NbS) against natural hazards such as rockfalls, landslides and snow avalanches. Traditionally used and formally managed for 150 years, today, their management is institutionalized through subsidies and management guidelines for practitioners. This makes them one of the most established NbS worldwide and an innovative case study for analysing how NbS become integrated into policies and practices, how governance barriers and enablers evolve around mature and well-established NbS and how NbS management responds to climate change.

Drawing on scientific literature, focus groups and interviews with experts and practitioners, we identify key governance enablers and challenges shaping protection forest management and analyse how climate change and synergies and trade-offs between the protection function, biodiversity conservation and other forest functions influence management decisions.

Our results show that protection forests benefit from strong enabling conditions, including effective subsidies, a robust legal framework, and a wide recognition of both their cost-effectiveness and their multifunctionality. Stakeholders noted that more biodiverse protection forests are more resilient, and their targeted management generally supports biodiversity targets - with some trade-offs and room for better exploitation of synergies remaining. 

Challenges threatening protection forest sustainability include high deer and chamois populations that cause browsing damage and limit forest regeneration and diversity, native species struggling to adapt to climate change, and invasive non-native species that are more resistant but have a lower protective value (e.g. due to a more shallow root system). Assisted migration of climate-proof tree species as replacements or complements is being considered, however, sparking new biodiversity debates. Other key barriers include workforce shortages, limited expertise on forest ecology and dynamics, and a lack of integrated planning between forestry and hazard management.

The Bern case illustrates the value of institutionalized NbS and the ongoing challenge of balancing hazard protection, biodiversity, and climate adaptation. This case provides insights for practitioners and decision-makers on integrating multiple ecosystem services into forest management, fostering and implementing NbS that support both hazard protection and biodiversity outcomes.