Introduction: Studies on how the altitudinal gradient determines community composition and structure in tropical high altitude grasslands are rare. Objective: To evaluate the plant community composition and structure and the relationship between altitude and soil properties along an altitudinal gradient of three granitic rock outcrops at the Serra do Brigadeiro State Park, southeastern Brazil. Methods: In each selected site, 100 plots of 1 × 1 m were established, totalizing 300 plots in the study area. We compared the floristic composition, relative coverage and abundance among sites. We performed an indicator species analysis and a Canonical Correlation Analysis to investigate possible relations between abiotic (soil and altitude) and biotic (indicator species abundances) variables. Results: We sampled a total of 9276 individuals belonging to 39 families and 102 species. Significant differences were observed among sites regarding composition, abundance, and coverage. Indicator species analysis revealed that 57 species (55.88%) were indicators. The distribution of abundances of the indicator species was correlated with environmental variables. Conclusions: It could be observed that altitude and soil play an important role in controlling community composition structure and species distribution in the highland grasslands studied.

Keywords: indicator species, mountain vegetation, rocky outcrops, plant coverage, soil-vegetation relationship