Land use optimization for synergistic economic growth and nitrogen, phosphorus as well as net carbon emissions reduction: a case study of the Dongjiang River Basin
摘要
Land use and land cover change (LUCC) intensifies the conflict between regional economic development and ecological protection, driving challenges such as increased carbon emissions and non-point source pollution from nitrogen and phosphorus. Achieving synergistic advancement of economic growth and emission reduction (SEGER) has thus become a critical but inadequately addressed objective in sustainable land use planning. To bridge these gaps, this study develops a novel integrated land use optimization framework specifically targeting the SEGER objective. Its core contribution lies in the coupling of a modified multi-objective optimization algorithm, decision-making method for plans, and a spatially explicit simulation model to reconcile economic and environmental trade-offs. The framework first proposes a Modified Reference Vector Guided Evolutionary Algorithm (M-RVEA), enhancing population initialization and selection mechanisms to better solve high-dimensional problems. The M-RVEA is then applied to optimize the land use structure for SEGER, generating a Pareto front. Subsequently, the Entropy Weight-Technique for Order Preference by Similarity to Ideal Solution (EW-TOPSIS) method impartially selects the optimal allocation scheme, which is finally translated into a spatially explicit 2030 land use pattern via the Cellular Automata-Markov (CA-Markov) model. Applied to the Dongjiang River Basin in southern China, this study compares four scenarios: 2020 baseline, 2030 natural development (ND), 2030 RVEA, and 2030 M-RVEA. M-RVEA demonstrates superior convergence and diversity on 3-/4-dimensional test function compared to NSGA-II/III and traditional RVEA. The optimized 2030 M-RVEA scenario, compared to 2030 ND scenario, significantly reduces net carbon emissions by 4.39 × 10⁷ tC, nitrogen emissions by 1.67 × 10⁶ kg, and phosphorus emissions by 2.69 × 10⁵ kg, while maintaining economic growth. This is achieved through a strategic reallocation: increasing forest and construction land at the expense of some cultivated and grassland. The results confirm the framework’s effectiveness in generating scientifically-grounded, spatially explicit pathways for synergistic land use management, providing an actionable tool for policymakers aiming to achieve regional sustainable development goals.