Species composition and diversity of flora in an abandoned mine in an island province in the Philippines: Implications for rehabilitation strategies

Understanding the floristic composition of degraded lands, such as abandoned mine areas, is crucial for guiding effective rehabilitation. This study assessed an abandoned copper mine in an island province of the Philippines, which remained unrehabilitated after operations ceased, to document its floral species composition and diversity. Ten quadrats were established to identify thriving plant species and evaluate their conservation status and diversity indices. A total of 42 species from 27 families were recorded, with Fabaceae and Pteridaceae most represented. Twenty-one species were native to the Philippines. Dominant species included Oldenlandia corymbosa, Pteris sp., Fimbristylis littoralis, Acacia auriculiformis, Stachytarpheta jamaicensis, and Nephrolepis cordifolia. Based on plant categories, vegetation was mainly composed of ferns (40%) and shrubs or small trees (38%). Diversity indices showed heterogeneous patterns among quadrats, with some exhibiting ecological balance, while others were dominated by only a few species—typical of metal-contaminated environments. Quadrat 4 (Q4) was the most balanced and diverse, suggesting that despite harsh site conditions, patches of vegetation continue to thrive. Future studies should investigate soil properties of Q4 to guide site-specific rehabilitation strategies.