Payment for ecosystem services - an efficient approach to reduce eutrophication?

International audience; More than 50 % of the waters entering the Atlantic Ocean between France and Great Britain (Channel) are below Good Ecological Status due to sedimentation, low oxygen levels, or excess nutrient load, which promotes cyanobacterial dominance. Economical losses in cyanobacteria infested lakes concern drinking water production, fishing and tourism activities. The most effective ways to improve water quality are to reducenutrient losses from lake catchments, but these reductions are, however, associated with costs. The project CPES (Channel Payments for Ecosystem Services) aims to develop PES (Payment for Ecosystem Services) schemes to improve water quality by reducing nutrient (both, nitrogen and phosphorus) losses with a catchment wide approach. The PES schemes will include land management interventions, ecosystemquality monitoring plans, economic models, commercial agreements, and stakeholder engagement plans. The project comprises 6 pilot studies within the British and French side of the Channel area. One of which is the multi-purpose reservoir Lac au Duc (touristic, drinking water, fishing), frequently suffering cyanobacterial blooms and its catchment in France. We are studying aspects of the PES approach from catchment assessment (hydrology, land use, nutrient emissions), aquatic ecology (dynamics of cyanobacteria and zooplankton, eutrophication), and economy (evaluation of public policies applied to agriculture and environmental economics, and design of PES). Aim is to test the efficacy of incentive supports by applying a ‘the user pays’ approach.