Floristic affinities in montane grasslands in eastern Brazil

Abstract

The montane grasslands of eastern and southern Brazil occur mostly at elevations above 900 m and are regionally distinguished as campos rupestres and campos de altitude, with the former having a more interior and seasonal climate and the latter a more coastal and humid climate. The floristic relationships between 13 sites of montane grasslands, distributed from north-east to south Brazil (roughly 13–28 °S), were analyzed on the basis of grass species composition. After a compilation of the published literature, the floristic lists were updated according to current taxonomic circumscriptions. The final list had 311 species within 72 genera. The genus Paspalum had the highest number of species (49), whereas 25 genera contained only a single species. Relatively many species (∼50%) were restricted to single study sites, and very few species were widespread. Multivariate analysis supported four groups (bootstrap values >70), primarily distinguishing between seasonal tropical versus humid temperate climates and secondarily between surrounding biomes (caatinga versus cerrado) in the northern tropical sites and geological substrates (granitic versus basaltic) in the southern temperate sites. Our study documents the effects of large-scale climatic and geological factors on the floristic differentiation of montane grasslands and contributes to knowledge of the major vegetation types occurring within Brazilian mountain systems.