Multi-Objective Optimization of Water and Land Resource Allocation for Ecological Function Enhancement in a Climate-Sensitive Alpine Basin: A Case Study of the Huangheyan Upstream, Yellow River Source Region

The ongoing warming–wetting trend is profoundly reshaping water and land resources (WLR) in alpine regions, challenging their ecological functions. Focusing on the Yellow River source region above Huangheyan Station, we developed a synergistic WLR allocation framework explicitly oriented towards ecological function enhancement. We systematically assessed the spatiotemporal evolution of WLR and key ecological functions from 2000 to 2020, and projected future dynamics for 2030–2060 under four SSP scenarios. A multi-objective optimization model was established to minimize water shortage, maximize water conservation capacity (WCC), maximize vegetation water use efficiency (WUE), and minimize soil erosion amount (SEA), solved using the Non-dominated Sorting Genetic Algorithm II algorithm (NSGA-II). The results indicate significant ecological improvements over the past two decades (Net Primary Production (NPP) +14.3%, WCC +67.9%, SEA −34.1%). Critically, the optimized allocation schemes demonstrated substantial benefits across all future scenarios, enhancing WCC by 4.6–20.2%, improving WUE by 0.6–10.7%, and reducing SEA by 3.9–9.1%. This study offers a useful reference for coordinating ecological conservation and resource management in climate-sensitive and ecologically fragile alpine regions.