Resilience of marginal grasslands and biodiversity management decision (REGARDS)

European marginal grasslands are biodiversity hot spots owing to ecological constraints, biophysical heterogeneity, and centuries of agriculture. Currently it is not clear whether these unique systems are vulnerable to ongoing environmental, socio-economic and political changes, or if they have developed a high resilience over their history of co-evolution between humans and ecosystems. In the latter case the limits to this resilience are unknown, and their prediction hazardous. This uncertainty lies largely in the poor knowledge of resilience mechanisms of both the ecological and human sub-systems, as well as those underpinning robustness or vulnerability of the entire system coupled through land management decisions and ecosystem services. REGARDS aims to unravel the mechanisms underpinning resilience of marginal grassland systems to global environmental and social change in order to enhance socio-ecological resilience from farm to regional level. We ask the following questions: 1) Can we identify safe parameter space vs. tipping points in the combined effects of changing climate, including extremes, and management on grassland ecosystems? 2) How does coupled above-belowground functional diversity buffer or amplify grassland ecosystem responses to combined changes in climate and management? 3) How do landscape structures enhance or decrease the resilience of ecosystem services? 4) Can multi-level governance structures facilitate fast adaptation to socioeconomic changes that affect biodiversity and the related ecosystem services? 5) Does regional integration and globalization enhance or threaten resilience through their effects on flows of goods and ecosystem services, people and information? 6) How do ecological and human processes combine to determine resilience of ecosystem services? REGARDS will address these questions for mountain grassland sites in Austria, France and Norway, where contrasted biophysical and human situations will allow us to explore complementary dimensions of socio-ecological resilience. Questions (1) and (2) will be addressed using an experimental approach combining manipulations of plant functional diversity, climate and management with state-of-the art analyses of soil microbial diversity and fluxomics (WP1&2). Historical analysis over the last 60 years will be used to quantify landscape functional structure and its effects on ecosystem services, thus addressing question 3 (WP3). Question (4) will be addressed by an assessment of how local, regional, national and EU programs affect farmers responses and resilience, accounting for the multiple factors influencing their decisions (WP4). Question (5) will be addressed by reconstructing exchanges with other regions of each site based on past land uses, and by comparing indicators of socio-ecological resilience through time and across sites (WP5). Finally we will build on this knowledge (questions 1-5) to address question (6) using a participative scenario-based approach (WP6). Scenarios varying openness of the human-environment system and governance structures will be defined with key local and regional stakeholders and decision makers. Evaluation of scenario outcomes in terms of biodiversity, ecosystem services, material well- being, and associated tipping points will be used to foster knowledge building about resilience at farm and local/regional levels.

REGARDS aimed to unravel the mechanisms underpinning resilience of marginal European grassland systems to environmental and social changes in order to enhance socio-ecological resilience from farm to regional level. We conducted research in the Central French Alps (Lautaret, Hautes-Alpes) and in Austrian Tirol (Stubai Valley). In climate manipulation experiments, plants and soil of traditionally managed grasslands showed a low resistance to drought but fast recovery, reflecting fast regrowth of dominant plants, fast response of their associated bacterial community and plant functional diversity. Conversely less managed plant communities showed higher drought resistance, reflecting stress tolerance. Management practices can thus mitigate yield reductions caused by extreme climatic events. Resilience also varies across ecosystem services, thus management for the resilience of provisioning services needs to consider consequences for regulating or cultural services. Historical analyses highlighted that spatial trade-offs in ecosystem services across land uses need to be considered in landscape planning and policies aiming to foster resilience of multifunctionality. Realizing the high local potential of grassland management adaptation requires supporting institutions and values. Regulatory institutions designed with farmers would enable farm adaptation and transformation while maintaining traditional practices. Further, the role of social and psychological factors, such as place attachment to reduce abandonment of marginal lands needs to be considered for adapting agricultural and environmental policies, which so far focus on economic factors.