Futur des services écosystémiques dans les forêts de montagne européennes soumises au changement climatique

International audience1. Ecosystem services (ES) from mountain forests are highly relevant for human societies. ES with a direct economic support function (e.g. timber production), regulatory services (e.g. protection from natural hazards) and cultural services (e.g. recreation) are likely to be affected strongly by a rapidly changing climate. To evaluate whether adverse climate change effects on ES can be counteracted by adapting management, dynamic models and indicatorbased assessments are needed. 2. We applied a forest dynamic model in case study areas of four European mountain regions and evaluated the future supply of four ES – timber production, carbon sequestration, biodiversity and protection against natural hazards – using state-of-the-art ES indicators. Forest dynamics were simulated under three management scenarios (no management, business-as-usual and alternative management) and five climate change projections for selected representative stand types in each region. We analysed potential trade-offs and synergies between ES and evaluated future changes among regions, forest stands, climate and management scenarios. 3. Impacts of climate change on the provision of multiple ES were found to be highly heterogeneous and to depend on the region, site and future climate. In the absence of large-scale natural disturbance (not considered), protection services, carbon stock and deadwood abundance (proxy for biodiversity) benefitted from no management in all regions. Negative impacts of climate change were evident for the provision of multiple ES but limited to the most severe climate scenarios and low-elevation stands. Synergies and trade-offs between the majority of ES were found to be sensitive to the choice of management strategy and – in some regions – to climate change. 4. Synthesis and applications. Management regimes in European mountain forests should be regionally adapted to stand and site conditions. Although in some cases alternative management regimes may be more suitable than current management for supporting multiple ecosystem services, adaptation options should be valuated carefully at the local scale due to the highly different magnitude of the impacts of climate change in different regions and along elevation gradients

Value-based ecosystem service trade-offs in multi-objective management in European mountain forests

Mountain forests provide a diverse range of ecosystem services (ES). In case of conflicting ES, trade-offs must be considered in forest resource planning. In this study, simulation-based scenario analysis and multi-criteria decision analysis is used to analyse expected utilities and value-based trade-offs in multi-objective forest management related to four key ES (timber production, carbon storage, biodiversity conservation, protection against gravitational hazards) in three European mountain regions. In each case study area a set of management alternatives including no-management were simulated over 100 years and ES quantified using ES indicators. Multifunctional goal scenarios are employed to aggregate partial ES utilities, accumulated RMSE between ES are used to quantify trade-offs. In two analysed case study areas no-management generated highest ES utilities for biodiversity conservation, carbon storage and protection against gravitational hazards. Alternatives based on small-scale silviculture combined timber production and biodiversity conservation very well. In all case study areas increasing goal preferences for timber production or biodiversity and nature conservation result in increasing overall trade-offs with rather decreasing overall utilities. In all case study areas the analysed managements support multiple ES and can thus be considered as multifunctional. Based on the presented analysis management alternatives could be further improved