Floristic Composition and Plant Diversity of Restored Mine Sites in Plateau State, North Central Nigeria

Tin mining activities on the Jos Plateau left extensive areas of degraded land that required ecological restoration to recover productivity and biodiversity. This study assessed the floristic composition and plant diversity of mine sites at different stages of post-mining restoration in Plateau State. Six sites were selected spanning newly restored, five-year-old, and ten-year-old restoration plots, with undisturbed grassland patches serving as reference sites. Vegetation was surveyed using quadrat methods along systematic transects, and species were identified, counted, and recorded. Shannon Diversity and Simpson Dominance indices were calculated for each site. Results showed a clear successional trend with increasing species richness and declining dominance with restoration age. Newly restored sites were dominated by ruderal herbs and pioneer grasses, while older restoration plots showed colonisation by secondary shrub species typical of montane grassland communities. However, even ten-year-old restored sites had significantly lower plant diversity than undisturbed reference grasslands, suggesting that full floristic recovery requires more than a decade. Soil physicochemical properties correlated positively with plant diversity improvement, particularly organic carbon content and available phosphorus. The study recommends accelerating restoration trajectories through active planting of native species with high ecological value and soil amendment to reduce the recovery timeline for mine-impacted lands. Keywords: floristic composition, mine restoration, plant diversity, Jos Plateau, Plateau State.