Abstract
The rupestrian grasslands vegetation occurs at the mountaintops of the Espinhaço Range harboring high number of endemic plant species. Despite its importance, some areas of rupestrian grasslands are under anthropogenic disturbance due to mining and trampling. The present study had two main questions: 1) Are the floristic composition and structure of rupestrian grasslands in areas impacted by mining similar to areas not subjected to mining? Are there tendencies to increase the abundances of exotic invasive and wild widespread plant species in areas impacted by mining or trampling? To evaluate our questions we sampled four rocky grasslands in Igatu, Andaraí, Chapada Diamantina, Bahia, Brazil: two areas where the mining activities stopped 15 years ago, one area under current disturbance due to trampling, but without mining historic, and a fourth area which is well conserved. The vegetation was sampled in 16 10x10 m plots, four in each site. The geographic distribution of each species was defined based in the literature. Cluster and ordination analysis were performed. We conclude that the floristic composition of the sites was affected by previous and current disturbances, but only the mining disturbance had strong effect in vegetation structure, with the conserved area harboring a great part of the Brazilian endemic species. The exotic and invasive plant Melinis minutiflora P.Beauv. occurred only at the disturbed sites, mainly in the mined sites, stressing that rupestrian grassland sites subjected to mining in the past should be monitored against invasive species.
Key words:
Chapada Diamantina; biodiversity conservation; ruderal species; disturbance; vegetation regeneration
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