Océane Bartholomée

Ecosystem services are benefits supplied by ecosystem to human societies. In France, recent legislation aims to include ecosystem service in environmental impact studies with the enactment of the Law for the recovery of biodiversity, nature and landscapes (2016). To do so, it is necessary to develop field methods for ecosystem service estimation. In this setting, a collaboration was established between the Laboratoire d’Ecologie Alpine and the environmental consultancy EGIS Environnement to answer the following question: how can ecosystem services be quantified at local scale?We studied two ecosystem services often cited in the global change context. The pollination service is essential for human food production. Given worldwide pollinator declines it is at the centre of scientific, citizen and political concerns. The service of global climate regulation by carbon sequestration by ecosystems is of major interest given the recent and coming climate changes.We investigated four key steps for developing a field protocol. First, the ecosystem service of entomophilous pollination has numerous definitions in the scientific literature. Thus, based on a literature review we built a conceptual framework for defining the pollination service and identifying quantifiable indicators and their measurement methods. We chose to define the pollination service as the ecosystem capacity to support entomophilous pollination, i.e. pollinating insect presence. Second, we worked on indicator selection for the pollination service estimation. Pollination capacity can be estimated through direct indicators linked to pollinator presence on the plot and through indirect indicators linked to feeding and nesting resources in the plot and in the landscape. We compared measures of these two types of indicators within orchards and grasslands. Our aims were to test consistency between both indicator types for the pollination service and the possibility of protocol simplification based on indirect indicators. Indirect indicators did not explain enough of the observed variability in pollinator abundance and richness to allow a protocol simplification.Third, we tried to simplify the estimation protocol of the ecosystem service of global climate regulation from measures of carbon stocks in grasslands and forests. We compared estimations obtained by simplified protocols to estimations obtained by a more complete protocol. We also quantified the uncertainties caused by these simplifications. The estimation protocol could be simplified for the two most important carbon pools: aboveground biomass in forests and soil organic carbon. Finally, to test the applicability of the simplified protocol of carbon stock estimations, we applied it on wetland plots. These plots were organized following in a state-and-transition model to test whether management decisions are likely to affect wetland carbon stocks. Management actions on aboveground biomass changed carbon stocks between herbaceous and forested wetland. Soil organic carbon, the major carbon stock in wetlands, was unchanged between the different studied stats, illustrating the difficulty to manage soil carbon stocks in the short term.This study shows that method development for field quantification of ecosystem service can lead to simple and reliable protocols. However, the development process is different for each ecosystem service.