Durant, D. and Kernéïs, E., 2024. Investigating the farm resilience of polder environments after seawater flooding: Results from Storm Xynthia (2010). Journal of Coastal Research, 40(5), 887–900. Charlotte (North Carolina), ISSN 0749-0208.

Climate forecasts predict that global warming will cause sea-levels to rise and will increase the frequency of storms in the future, thus also increasing the risk of submersion of coastal agricultural areas. Yet very few studies examine the consequences of seawater flooding, from either an agricultural or an environmental point of view. This study therefore investigates the resilience of coastal farming systems through the case study of the Saint Laurent de la Prée research farm hit by the Storm Xynthia in 2010. Two aspects of resilience are analysed here: (i) the soil characteristics of the system (indicators: salinity, sodicity and structural stability) after the submersion, and the system's ability to recover its productive capacity on croplands (crop yields) and on permanent grasslands (fodder production); and (ii) the ecological resilience of permanent grasslands (indicators: species richness and diversity). Results showed that the system recovered its productive capacity in 2012, so after two years, when the research farm engineers recorded a return of the crops and grasslands to a production level that they considered satisfactory. For crop soils, there was a quick recovery of salinity levels, but the structural stability after the storm was largely degraded and had not totally recovered by 2012. On grasslands, the farm suffered two successive years of low grassland productivity, partially due to a temporary shift in plant species' composition. Finally, two dimensions of resilience are discussed here: (i) the speed of recovery; and (ii) the ability to learn from the storm, in view of the increasing risks of coastal submersion in the future. As it appears that flood protection policy must consider local and long-term impacts of seawater flooding on agricultural lands, this study can provide useful information for further research on the foresight scenarios and adaptive strategies required.