Floristic woody composition of revegetated mining sites in the Brazilian Federal District

Resumo

The mined area in the Brazilian Federal District - BFD is proportionately five times larger than the national average, and the restoration of plant communities at these sites is both necessary and mandatory. The use woody species to restore degraded ecosystems is a common practice, and this study aimed to identify and assess the floristic composition of woody species introduced in mining sites of the BFD as a mean of ecosystem restoration. The floristic survey was conducted by sampling of groups of one hundred individuals, repeated until sampling sufficiency was achieved. 4,500 plants were sampled in ten sites, which housed 92 autochthonous and 21 allochthonous woody species. The plant communities surveyed consisted of between 13 to 62 species, planted at low density - 467 ± 222 plants ha-1. The preferential use of autochthonous species in the revegetation projects resemble the standards recommended by successional restoration models, but the floristic diversity and plant density in these sites fall below the values deemed ideal. The 92 autochthonous species include representatives of various habitats, ecological groups and dispersal syndromes. These 92 species currently in use may be regrouped in initial plant communities denser and more diverse than those found in the revegetated sites. The plant communities in the surveyed sites were composed almost exclusively of arboreal species and such pattern may lead succession towards the formation of ecosystems dissimilar to the original savanna formations present in the studied locations.