Seed bank and aboveground vegetation of Atlantic Forest re-growing on mining tailings in Mariana: Highlighting diversity patterns of functional groups

Natural regeneration after mining activities depends largely on the soil seed bank (SSB) and aboveground vegetation (AGV) richness and composition. We evaluated the species diversity pattern of the SSB and AGV on soil and technosol across second-growth Atlantic Forests (SGFs) after mining tailings deposition in Mariana, southeastern Brazil. Two second-growth Atlantic seasonal semideciduous forests of different stand ages were selected: a 3-year-old stand of SGF re-growing on tailings (SGF tailings) and a 30-year-old stand of native reference forest not affected by tailings (SGF nontailings). Overall, the results showed significant differences in forest attributes (species richness and composition) in the SSB and AGV between the two forest patches evaluated (SGF tailings and SGF nontailings). Moreover, both nonzoochoric and zoochoric dispersed species of AGV showed significant differences between second-growth forests, with higher variability of community-weighted mean in SGF tailings. The result shows smaller differences in species richness between forest types for both SBB (ranging 85 and 90 species) and AGV (similar to 55 species). Despite the time difference between the secondary forest and the absence of zoochoric species in the tailings seed bank, the AGV that are re-growing on mining tailings presented a high proportion of zoochoric species. This pattern of species richness and community composition variability observed in the technosol seed bank, and AGV that are re-growing after the deposition of mining tailings are important recovery indicators for plant communities affected.