Quantifying carbon storage decline under land degradation in the Central High Atlas: A case study of the Oued Ahansal watershed (2000–2022)

Carbon sequestration is an essential ecosystem service that contributes to climate regulation and enhances ecosystem resilience. This study evaluates changes in carbon storage in the Oued Ahansal watershed, Central High Atlas, Morocco, from 2000 to 2022 using the InVEST model. Land use and land cover maps derived from Landsat 5 and Landsat 8 images were classified into four categories: dense forest, open forest, agricultural land, and bare soil. Carbon stocks were estimated for aboveground biomass, belowground biomass, soil, and dead organic matter. Results show a marked decline in high-carbon storage areas, which decreased from 55.5% in 2000 to 11.9% in 2022, while low-carbon zones increased from 5.1% to 80.8%. This reflects accelerated land degradation linked to vegetation loss, overgrazing, and recurrent droughts. The findings highlight the urgent need for reforestation, assisted natural regeneration, and sustainable land management to restore the carbon sink capacity of degraded mountain ecosystems.