Gestion des pâturages pastoraux, échanges de gaz à effet de serre et potentiel de séquestration du carbone dans les écosystèmes arides de Djibouti : une approche intégrée pour des transitions durables

This PhD project falls under BEST's scientific axis: 'Quantifying and Analyzing the Societal Impact of Global Change.' It targets the arid pastoral ecosystems of Djibouti, which face challenges similar to those in the drylands of East Africa (Ethiopia, Horn of Africa), including soil degradation, invasive species, water scarcity, pressure on woody vegetation (a source of energy), and climate variability. Objectives: -Measure and model greenhouse gas (GHG) fluxes (CO₂, CH₄, N₂O) at high spatial resolution to refine national inventories (transitioning from a Tier 1 method—default IPCC emission factors—to Tier 2/3 methods with local data). -Assess the carbon sequestration potential in soils and vegetation by comparing shrub-dominated areas with open grasslands. -Propose nature-based solutions to enhance the climate resilience of pastoral communities, aligning with SDGs 2 (Zero Hunger), 13 (Climate Action), and 15 (Life on Land). The project follows an integrated approach (WEFE Nexus) and adopts an interdisciplinary perspective (climate, ecology, animal science, social science) and a participatory framework (involving pastoralists, policymakers, and consultants) to analyze interdependencies between: -Water: Management of watering points and watershed dynamics. -Energy: Reducing dependence on woody biomass (a major driver of deforestation) through sustainable alternatives (e.g., biogas). -Food: Food security linked to rangeland and livestock productivity. -Ecosystems: Preservation of biodiversity and ecosystem services (e.g., soil fertility, pollination). Methodological Innovations: -Field data: GHG flux measurements, pastoralist surveys, transects to assess vegetation cover (LAI, diversity), soil characteristics (pH, texture, organic matter), and herd structure. -Modeling: Simulation of carbon/water/nutrient dynamics (dynamic vegetation models and AI tools) to predict the impact of pastoral practices. -Regional upscaling: Collaboration with Haramaya University (Ethiopia) for comparative analysis in the Horn of Africa's drylands. -Participatory science: Involvement of pastoralists in data collection and co-design of solutions. -Policy analysis: Evaluation of incentives for carbon sequestration. Societal and Policy Impacts: -Capacity building: Training pastoral communities in sustainable management and carbon sequestration mechanisms. -Support for Djiboutian institutions (e.g., Ministry of Agriculture) in developing climate policies. The project will rely on both academic partnerships (ILRI, Haramaya University) and non-academic partnerships (pastoral communities, Djibouti's Ministry of Agriculture, PASTOC consultancy). École doctorale : SDU2E - Sciences de l'Univers, de l'Environnement et de l'Espace Direction : Dominique SERCA Financement : MSCA COFUND BEST