EcoCN
EcoCN: Evaluation of the impacts of Nature-based Solutions on ecosystems and the C and N cycles of the Lèze and Gascogne rivers to the Garonne
Scientific supervisors: Sabine SAUVAGE and Clément FABRE
Host institution: CNRS
Context
Human activity has a significant impact on the biogeochemical cycles of carbon (C) and nitrogen (N), water quantity and quality, soil health, and biodiversity. The EcoCN project aims to conduct an integrated assessment of the impacts of implementing Nature-based Solutions (NbS) on the dynamics of C, N, and biodiversity at the watershed scale, as well as their benefits for socioeconomic trajectories and water resources, across various study sites forming a territorial gradient within the Pyrénées-Garonne Workshop Area.
EcoCN relies on action research and co-creation initiatives with local stakeholders in areas where NbS are currently being implemented or are planned for implementation (Gascogne Living Lab, the Auradé and Lèze river basins, and the Garonne-Ariège Confluence Regional Nature Reserve). The project focuses on a set of four complementary and geographically close agricultural sites, situated along a dual gradient of upstream-downstream and agricultural and urban intensification.
The project
The project aims to test, calibrate, and model the effectiveness of NbS in regulating C and N fluxes in soils, surface water, and groundwater, as well as into the atmosphere, and in influencing biodiversity dynamics. The methodological approach combines instrumented environmental monitoring, territorial analyses, and integrative and predictive eco-agro-hydrological models. Particular attention will be paid to developing prospective territorial scenarios that account for climate change, the natural functions associated with NbS, agricultural practices, and urbanization. The modeling tools will couple semi-distributed eco-agro-hydrological models, C/N balance models, and land-use models to simulate the combined effects of NbS in different evolutionary contexts.
The results will be extrapolated to the Garonne River basin through modeling, using a multi-site approach, and presented in the form of narrative maps that clearly illustrate the integrated analysis. This will help identify the conditions under which NbS are effective in influencing the dynamics of C and N fluxes, biodiversity, and water resources. Deliverables will include operational indicators, spatialized decision-support tools, and scenarios co-developed with local stakeholders, which will be used to support the development of NbS at the watershed scale.