Mapping territorial vulnerability to wildfires: A participative multi-criteria analysis

Abstract

The Mediterranean region is routinely affected by forest fires, with adverse consequences on ecological, infrastructural, and socioeconomic assets. In a context of climate change, it is crucial for fire prevention and suppression to be able to identify locations where assets are most at risk, due to environmental, physical or socio-economic reasons. Besides, this knowledge needs to be developed together with operational services and field experts to ensure their application. So far, fire risk research has largely focused on fire behavior, effects, and model simulation. In this article, we show how the concept of vulnerability can provide a flexible and relevant framework for assessing fire risk and be evaluated using a spatial multicriteria decision analysis method (MCDA) - the Analytical Hierarchy Process (AHP)- based on both quantitative data and expert judgment gathered through a participative approach. We focus on South-Eastern France, a region characterized by high economic and environmental stakes and heavily affected by wildfires. We develop a series of spatialized indicators using ecological, land-use and sociodemographic data which we aggregate to produce vulnerability maps for three categories of assets: population, ecosystems and infrastructures. An ex-post workshop was organized with field experts to put both the approach and results into discussion. Results reveal significant differences in indicators’ perceived contributions to risk and vulnerability and enable appraising the contribution of sociodemographic factors, often overlooked in the literature. We also reveal differences in spatial patterns across both vulnerability subcomponents and exposed assets, helping identify primary and secondary vulnerability hotspots and underlying drivers. Consideration of multiple subcomponents of risk and vulnerability may help local decision makers prioritize how and where measures should be implemented, while the use of MCDA favors experience and knowledge sharing and among stakeholders while providing a basis of discussion.