LAUSR

Carbon dioxide released in the atmosphere and dissolved in water leads to acidification. Relatively few studies have focused on fresh waters, where biocalcifying species are more readily impacted by changes in pH. Sensitivity to pH of an endangered calcium-demanding organism, the crayfish Austropotamobius pallipes, was investigated in the Pinail nature reserve, a natural system with 3000 permanent ponds, some inhabited by the crayfish and others not, originally due to human introduction. From the 14 chemical parameters measured in this study, the main limiting factor preventing crayfish establishment appears to be water acidity (pH < 6.8), which affects calcification, molting, growth and reproduction. We predict that 20% of the Pinail populations will disappear by 2060 due to freshwater acidification with the present level of fossil fuel consumption. Ongoing and future restoration projects for conservation of this heritage crustacean must select hard water with the highest water pH (> 7).