COMPOSIÇÃO FLORÍSTICA E ESTRUTURA DAS FLORESTAS ESTACIONAIS DECÍDUAS SOBRE CALCÁRIO A OESTE DA CADEIA DO ESPINHAÇO, MINAS GERAIS, BRASIL

摘要

(Composição florística e estrutura das florestas estacionais deciduas sobre calcário a oeste da Cadeia do Espinhaco, Minas Gerais, Brasil). Visando contribuir para o conhecimento dos fragmentos de florestas estacionais deciduas ainda existentes%(Floristic composition and structure of seasonally dry-deciduous tropical forests on calcareous rocks of the westside of the Espinhaco Range, State of Minas Gerais, Brazil). Aiming to contribute to a better knowledge of the remaining fragments of seasonally dry deciduous forests at several areas in Brazil, and of their relationships to the surrounding vegetation, this article presents a physiographic characterization and the structural and floristic aspects of six patches of this type of forest, found on calcareous outcrops (Bambui Formation) that lie along the west side of the Espinhaco Range in Minas Gerais state. The main character of those forests is the deciduous pattern, resulting on a marked physiognomy which is conspicuous from the distance during the dry season. The similarity of the flora of the six studied sites to other Brazilian deciduous forest was also investigated. 296 species of vascular plants were found in the forests on calcareous rocks flanking the Espinhaco, with Leguminosae (33 spp.), Euphorbiaceae sensu stricto (18 spp.), Bignoniaceae (13 spp.), Malvaceae sensu lato (13 spp.), Apocynaceae sensu lato (11 spp.) and Sapindaceae (11 spp.) being the richest families. All other families have less than 10 species in those forests. The floristic comparison of the woody component of the forests studied at Santo Hipolito and Serra do Cipo sites showed low similarity (Jac-card index 17,85%, Sorensen index 30,30%), with only 25 species in common out of a total of 165. Likewise, the comparison between these two forests to other Brazilian deciduous forests (Rio Parana Basin in Goias and Atlantic Forest on calcareous soil in the Alto Ribeira, Sao Paulo) showed lower similarity (ISj less than 5,5 % and ISso less than 10%).