Reviving Ecosystems: Vegetation Structure and Biodiversity Recovery in Reclaimed Coal Mining Areas of Kalimantan

Post-mining landscapes in tropical regions often suffer from severe ecological degradation and biodiversity loss, posing long-term challenges to their sustainability. This study investigated vegetation structure and biodiversity recovery across eight reclaimed coal mining sites in Kalimantan, Indonesia, with reclamation ages ranging from 6 to 18 years. A total of 80 stratified vegetation plots (10 × 10 m) were surveyed, recording 46 species from 23 families across the herb, shrub, and tree strata. Key ecological metrics, including the Shannon-Wiener Index (H′), Importance Value Index (IVI), and Sørensen Similarity Index, were applied to assess diversity, dominance, and community similarity. The results indicated that species diversity significantly increased with reclamation age (H′ = 1.42–3.11; F = 5.27, p < 0.01), confirming progressive ecosystem recovery. Vegetation similarity across sites remained low (10–57.78%), suggesting diverse successional trajectories. Dominance by Acacia mangium and Albizia chinensis in the upper strata was common, whereas Ottochloa nodosa and Chromolaena odorata contributed to soil stabilization. Fabaceae was the most dominant family, and the critically endangered Peronema canescens was identified, underscoring the conservation potential of reclaimed habitats. Multivariate regression and heatmap analyses revealed that biodiversity (H′) was negatively correlated with rainfall (r = –0.69) and temperature (r = –0.41), and positively correlated with humidity (r = 0.54) and wind speed (r = 0.53). Cluster and NMDS analyses confirmed spatial biodiversity patterns and informed site-specific conservation priorities. Mixed-species revegetation consistently supports higher biodiversity than monoculture. These findings highlight the importance of time, microclimatic regulation, and adaptive species selection in post-mining restoration efforts. By integrating biotic and abiotic interactions, this study provides a robust ecological framework for designing resilient, biodiversity-rich, and self-sustaining reclamation landscapes in the future.