An agricultural vulnerability assessment to droughts in the Alps: exploring indicators’ contributions at regional level

Recent drought events highlighted the vulnerability of the European Alps to unexpected conditions of reduced water availability. The drought conditions led to a wide range of impacts especially affecting agriculture. Impacts were not only triggered by the natural hazard itself but also by the level of regional exposure and vulnerability. Nevertheless, the characterization of the exposure and vulnerability in risk assessments still represents a challenging task due to the specific knowledge needed to depict regional conditions and its sparse quantitative high resolution data.

Our study aims to identify the main indicators affecting vulnerability and explore their contribution to the final drought risk in agriculture. We selected the Podravska region in Slovenia and the Thurgau canton in Switzerland. Both are case studies of the Alpine Drought Observatory Interreg project due to recent drought impacts in agriculture. 

Overall, a total of 31 indicators describing vulnerability to agricultural drought impacts was identified by local experts with 12 common indicators for both study areas. The majority of the indicators was solely identified for either Thurgau or Podravska demonstrating each region's specific characteristics. The indicators covered a broad range of aspects, such as geographic conditions (e.g. elevation, south facing), hydrological aspects (e.g. distance to large water bodies), soil characteristics (e.g. water holding capacity), agricultural practices (e.g. intensive farming), agricultural infrastructure (e.g. irrigation infrastructure), farmers' education, and policies (e.g. compensations). For each indicator we collected quantitative spatial data, removing those for which no information was available. Moreover, we normalized the selected indicators and combined them into final regional maps following two weighting scenarios: the equal weighting scenario, with all indicators having the same weight and the expert weighting scenario, where weights were assigned by the involved experts. In the Thurgau case the experts assigned more weights to the indicators related to the soil characteristics (e.g. “water holding capacity” and “humus content”) while for the Podravska case indicators related to farms position and type (e.g. “accessibility to local food market” and “farm diversification”). Final vulnerability maps for the two weighting scenarios and case studies will provide insights into the main vulnerability hotspot to drought, highlighting the main contributing indicators as well as those indicators initially identified by the experts for which no regional data is available.

Overall, this study highlighted the need of integrating the widely used equal weighting scenarios with qualitative knowledge and narratives from key experts. This approach can improve the understanding of agricultural vulnerability assessments to drought events supporting the implementation of adaptation strategies and plans in the Alpine region.