Drivers of Land Cover Change and Their Implications for Carbon Storage in the Ratuwa River Basin, Churia Region, Nepal

Land use and land cover change (LULCC) in the Churia region of Nepal has accelerated over recent decades, with uncertain consequences for carbon storage and climate regulation. This study examined the drivers of land cover change and quantified their implications for carbon storage in the Ratuwa River Basin (1,245 km²) from 1990 to 2020. Using Landsat imagery (1990, 2005, 2020) with a Random Forest classifier, we produced land cover maps achieving >88 % accuracy. Drivers were analysed using logistic regression and semi structured household interviews (n=90). Carbon storage was modelled using the InVEST carbon model, calibrated with field measurements from 150 sample plots. Forest cover declined by 25 % (17,031 ha), while agricultural land expanded by 35 % and settlements by 431 %. Proximity to roads (OR = 0.81 per km) and settlements (OR = 0.75 per km) and population density (OR = 1.45 per 100 persons km⁻²) were the strongest drivers of forest to agriculture conversion. Total carbon storage decreased by 2.52 million tonnes ( 14.7 %), equivalent to an average annual emission of 308,000 t CO₂. Forest to agriculture transitions accounted for 78 % of the carbon loss. Despite national forest recovery trends in Nepal’s mid hills, the Ratuwa Basin continues to lose carbon at an alarming rate. These findings highlight the urgent need for targeted conservation interventions. We recommend establishing a spatially explicit, incentive based programme that prioritises high carbon, high risk forests within 2 km of roads and settlements, combined with assisted natural regeneration of degraded shrublands, financed through REDD+ results based payments.