Upper montane grassland structure within six subranges of Serra do Mar, Southern Brazil

ABSTRACT The phytosociological structure of upper montane grasslands (high altitude grasslands) was studied in six subranges of Serra do Mar. Throughout 324 (1 m2) plot samples, we identified 195 taxa out of 280 taxa previously found in a floristic survey. Besides the general analysis of these communities, five physiognomies (synusiae) of these grasslands were previously determined based upon the species with greater cover. Cryptangium triquetrum and Croton mullerianus had the highest phytosociological importance value among the upper montane grasslands sampled in the present study. The first species was the most important of the grassy physiognomy of all sampled subranges and the second one of the shrubby physiognomy within three subranges. Chusquea pinifolia, Machaerina austrobrasiliensis, Deschampsia caespitosa, Gleichenella pectitata, Tibouchina dubia, Xyris stenophylla, Eryngium koehnearum and Eriochrysis holcoides were also structurally important. Although considerable species richness has been observed, the dominance of one or few species in the community was common in all subranges and physiognomies. In a brief comparison with upper montane vegetation studies (mainly on rocky outcrops) carried out in Southeastern Brazil, a low sharing of species was verified. Furthermore, the scarcity of studies in the literature regarding floristic and sociological structure of upper montane grasslands hampers a deeper analysis at level of species.