Dynamics of forest restoration in riparian ecosystems following tin mining in the Central Amazon

Riparian forests are highly productive and biodiverse ecotonal systems but are frequently degraded by anthropogenic activities such as mining. In areas with severely altered soils and limited propagule availability, active restoration through seedling planting is considered the most suitable approach. This study evaluated vegetation dynamics and ecological diversity in riparian ecosystems undergoing active restoration following tin mining in the Central Amazon. Eight restored sites of different ages (2.5–10 years) and one mature reference forest were assessed. A total of 58 permanent plots were established and distributed proportionally to the size of each site. A hierarchical sampling design was adopted, with 900 m 2 plots used to monitor planted species and 150 m 2 subplots used to assess natural regeneration. The reference forest exhibited the highest diversity based on Hill numbers. Restored sites showed high variability in diversity, with the 8-year-old ecosystems presenting the highest values. Species composition analysis revealed the formation of two distinct groups. Pioneer species showed the highest Importance Value Indices, particularly in the youngest ecosystem (RF_2.5H). The regenerating community was predominantly composed of tree and shrub species (46% each). Clitoria fairchildiana exhibited the greatest increases in diameter and height, indicating that active restoration has been effective in promoting the ecological recovery of post-mining riparian environments.