Valuation of wetland ecosystems services. Some methodological principles (In French)

We all have become aware of the essential contribution of ecosystems to the human welfare. This is a strong driver for taking into account ecosystem services within decision processes. But the connection between ecosystems and theirs services is frequently neither readily apparent nor easy to measure. A lot of studies have been, and are always, dedicated to an evaluation of those services. Some are aiming a biophysical measure of the benefits, others try to reveal an economic value. Unfortunately, we find little evidence of ecosystem services based on clear economic or biophysical principles. This paper is a try to contribute to a better identification of arising problems and principles that should be adopted.