Floristic, phytossociology and phytogeography of the high-altitude vegetation of Serra da Mantiqueira Meridional, southeastern Brazil

Author(s)

Leonardo Dias Meireles

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2009-11-27

Examining board members

George John Shepherd; Ary Teixeira de Oliveira Filho; Fresia Ricardi Branco; Ingrid Koch

• Advisor: George John Shepherd

Abstract

The "Serra Fina" is the name given to a block of the Serra da Mantiqueira, a mountain chain that forms the boundary between the states of Minas Gerais, São Paulo, and Rio de Janeiro, southeastern Brazil. The Serra Fina largely corresponds to a massif of alkaline rocks and forms the highest part of the range, rising to more than 2500m at several points. It offers an exceptionally extensive altitudinal gradient, with the occurrence of several high-montane vegetation formations. These formations are still relatively well-conserved, but are very poorly known. The main objectives of the present study were to analyze the floristic composition of some of the high-montane vegetation types, describe and analyze the phytosociological structure of the cloud forests, determine the degree of similarity between these forests and other montane forests in Brazil and to investigate possible explanations of the patterns seen, especially with regard to climate changes in the quaternary. A total of 393 species, of which seven are probably new to science, were collected in the grasslands, "candeia" scrub and cloud forests. The greatest species-level richness was found in the families Asteraceae, Poaceae, Melastomataceae, Rubiaceae, Cyperaceae, Fabaceae, Myrtaceae, Orchidaceae and Ericaceae. Two new species of Asteraceae, confined to grasslands above 2500m have been described and illustrated, and the remainder await more detailed studies by specialists. The species richness encountered demonstrates the importance of the contribution of high altitude areas to the overall diversity of the Atlantic Forest of eastern Brazil, and the phytogeographic importance of the Serra Fina with a large number of endemic species or species with restricted distributions with strong links to the Andean flora of western South America. The forests showed a number of characteristics typical of cloud forests, such as low richness, high density and a reduced canopy, with Myrsinaceae, Myrtaceae, Symplocaceae and Cunoniaceae as the most important families. The Serra da Mantiqueira upper montane forests showed their greatest floristic similarity to be with the cloud forests of southern Brazil and to some extent with the upper montane forests of the interior of Minas Gerais and the crest of the coastal range ("Serra do Mar") in São Paulo, though with a somewhat differentiated floristic composition. Similarities with the surrounding forest matrix at lower altitudes were much less. Models of potential distribution for montane forest species using scenarios for Late Quaternary conditions suggest that extensive modifications of currently observed distributions are likely to have occurred, with many species occupying much lower altitudes and latitudes, together with much greater longitudes. These results suggest that forests similar in composition to current upper montane forests may have occupied much more extensive areas in the past, forming an almost continuous forest that has subsequently been fragmented and confined to high mountain areas in the east-south Brazil. (AU)