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

Abstract

-(Upper montane grassland structure within six subranges of Serra do Mar, Southern Brazil). The phytosociological structure of upper montane grasslands (high altitude grasslands) was studied in six subranges of Serra do Mar. Throughout 324 (1 m 2 ) 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.

A new modern pollen dataset describing the Brazilian Atlantic Forest

“…1. The high elevation grassland eco-physiognomy is commonly observed in southeast Brazil at mountain ranges above elevations of 1800 m and represents a highly fragmented biome which harbours rich floras and high endemism (Safford, 1999a(Safford, , 2007Scheer and Mocochinski, 2016). The landscape consists of a series of cool-humid, mountaintop grass and scrubland areas with 11% of the plant species directly shared with the Andes (Safford, 1999b).…”

“…The landscape consists of a series of cool-humid, mountaintop grass and scrubland areas with 11% of the plant species directly shared with the Andes (Safford, 1999b). It is also the highest, coolest plant community in the cold-humid tropics of eastern South America (Safford, 1999b (Scheer and Mocochinski, 2016). Differences can be observed in composition of this eco-physiognomy, in particular in some places as in mountaintops, only one species can be largely dominant (Safford, 1999b).…”

“…Among the main plant families are Asteraceae, Polypodiaceae, Melastomataceae, Orchidaceae, Poaceae, Lamiaceae, Lycopodiaceae, Cyperaceae, Ericaceae and Rubiaceae, and among the most represented genera are Baccharis, Leandra, Tibouchina, Polygala, Peperomia, Habenaria and Senecio . Tree taxa such as Escallonia, Weinmannia and Myrsine are also frequent in the Andean forest, while Lagenocarpus triqueter (Boeckeler) Kuntze (Cyperaceae) and Croton muellerianus L.R.Lima (Euphorbiaceae) are among the most common herbs (Scheer and Mocochinski, 2016). Differences can be observed in composition of this eco-physiognomy, in particular in some places as in mountaintops, only one species can be largely dominant (Safford, 1999b).…”

The southern Brazilian tropical forest during the penultimate Pleistocene glaciation and its termination

“…High Poaceae and Asteraceae frequencies together with tree taxa characteristic of high‐elevation grassland, Myrsine , Ilex and Symplocos (Fig. ) (Scheer & Micochinski, 2016; Portes et al, 2020), suggest a landscape of cold grassland with sparse conifers and low‐standing tree species. The taxa associated with low temperatures ( Araucaria , Podocarpus , Acaena , Ephedra ) were not found in a modern pollen rain study of the high‐elevation grassland of the State of Rio de Janeiro (Portes et al, 2020) where today's mean temperature is probably too high for their growth.…”

“…Today, a few Podocarpus sellowii Klotzsch ex Endl. trees grow at the state park ‘Serra do Mar’ near Colônia, in open vegetation at ~850 m asl, which is a low elevation compared to that of other Brazilian altitudinal grasslands (Garcia & Pirani, 2003, 2005; Scheer & Mocochinski, 2016).…”