Moving towards a comprehensive evaluation of ecosystem-based disaster risk reduction: The example of agroforestry for flood risk reduction

Abstract

Nature-based solutions (NbS) have received increased interest as cost-effective contributors to addressing societal challenges, with ecosystem-based disaster risk reduction (Eco-DRR) being the specific approach for reducing disaster risk under the NbS umbrella. Ecosystem services (ES) provided by Eco-DRR measures are known to contribute to reducing all three components of disaster risk. Yet, Eco-DRR evaluation falls short of recognising this, and this hampers its strategic placement and effective use. This paper addresses the challenge of evaluating the impact of Eco-DRR measures on reducing hazard, exposure and vulnerability. The methodological approach for Eco-DRR evaluation is developed for agroforestry as an example of ecosystem-based measure for flood risk reduction. The literature review on ES provided by cropland versus agroforestry provided the basis to elaborate on how the quantitative evaluation of such a measure for flood risk reduction could be realised in a next step. An additional literature review served to create a look-up table on the effects of agroforestry on hydrological processes in comparison to cropland. This can serve as input for re-running the hydrological model and comparing the hazard before and after the agroforestry implementation. The paper also captures the effects of agroforestry implementation on social and ecological vulnerability through changes in ES provision. Changes in ES provision resulting from the implementation of an agroforestry measure on cropland were related to social and ecological vulnerability using a deductive approach. The concept for comprehensive evaluation developed in this paper provides the groundwork for evaluating the risk reduction potential of Eco-DRR with reference to a tailored risk assessment.