Strategies for adapting viticulture to climate change: a participatory modeling approach within a mediterranean catchment

International audienceClimate change may have negative impacts on agriculture, especially under Mediterranean climate. In the South of France, grapevine is mostly grown under rainfed conditions and water management will be more and more determinant to maintain a wine-growing activity. Various adaptation levers to water scarcity have been explored: irrigation, plant material, planting density, training system, soil management, etc. Local adaptation strategies may combine these adaptation levers into diverse cropping and farming systems, when considering current and future water resources. This paper presents a methodology that articulates a participatory approach with modeling tools, in order to carry out a multi-scale assessment of strategies of adaptation to climate change. The study starts with the design of site specific adaptation strategies with stakeholders in a medium-sized catchment of the South of France. Then, these adaptation strategies are evaluated through the development of an ad-hoc model. First, we built a conceptual model with the stakeholders to raise climate events, impacted processes, adaptation levers, their implications and requirements. Second, we coupled numeric models to fit the stakeholders' conceptual model. Third, spatialized strategies were defined with stakeholders and quantitatively evaluated under future climate scenarios RCP 4.5 and RCP 8.5. First results show that not all the practices and processes highlighted by stakeholders can be simulated with the existing tools, e.g. vine microclimate, sunburn damages, vine mortality, etc. This gap tends to be reduced through interactions with stakeholders and collective validation. The ad-hoc model is composed of three field-scale models-phenology, water balance, yield formation-integrated in a landscape modeling platform. The final model allows to capture part of the diversity of cropping and farming systems within the catchment as described by stakeholders in the baseline situation. The next step is to build and evaluate the alternative strategies. Through this study, we suggest that an integrative assessment combining adaptation levers in time and space, is relevant to define locally adapted response to climate change