Evaluating reclamation effectiveness and ecosystem recovery trajectories following tropical bauxite mining in Indonesia

Post-bauxite mining reclamation in tropical regions faces major ecological challenges, including soil disturbance, nutrient limitation, and unfavourable chemical conditions that constrain ecosystem recovery. Evaluating reclamation effectiveness is therefore essential for supporting sustainable post-mining land management. This study assessed soil and vegetation recovery trajectories across a 3–10 year reclamation chronosequence in post-bauxite mining areas of West Kalimantan, Indonesia. Soil physical and chemical properties and vegetation attributes were compared across reclamation stages and the adjacent natural forest, serving as a reference ecosystem. Data were analysed using analysis of variance, correlation analysis, linear regression, and Principal Component Analysis. The results showed asynchronous recovery between soil and vegetation components. Soil properties recovered relatively rapidly, reaching 90.4% of reference conditions, whereas vegetation complexity recovered more slowly at 66.6%. Aluminium saturation remained high in younger reclamation sites and was negatively associated with vegetation development, indicating that soil chemical constraints may limit long-term ecosystem recovery. In contrast, soil organic carbon showed a strong positive relationship with vegetation biomass (r = 0.93), highlighting the importance of soil quality improvement for vegetation establishment. The findings indicate that current reclamation practices were effective for improving early soil functionality and vegetation establishment, but less effective for restoring biodiversity and long-term soil chemical stability. These results highlight the importance of integrating soil amelioration, biodiversity-oriented revegetation, and long-term ecological monitoring into reclamation management frameworks for tropical post-mining landscapes.