Estudo florístico e ecológico das briófitas da Serra Negra (Minas Gerais) e sua relação com outras áreas do sudeste do Brasil

Abstract

Bryophytes are a paraphyletic group of terrestrial plants that assembles three monophyletic divisions: Bryophyta (mosses), Marchantiophyta (liverworts) and Anthocerotophyta (hornworts). In Brazil, the majority of the studies regarding bryophytes deals with floristics, however the knowledge of Brazilian bryophyte flora is still poor. In Minas Gerais, the Serra Negra is situated among Rio Preto, Santa Bárbara do Monte Verde, Lima Duarte and Olaria municipalities and has an altitudinal range of 800m to 1968m. The vegetational composition is formed by a mosaic of forest fragments and rocky outcrops. The aims of this study were to recognize and to study the bryoflora of Serra Negra in Minas Gerais state, to analyze the local bryofloristic similarity with others areas in Brazilian Southeastern Region, and to investigate environmental factors that influence the distribution of these species. The specimens were collected by “método do caminhamento”, in pre-existing trails of different physiognomies in order to investigate the whole area. For ecological analyses, it was elaborated a database with 621 species, including those ones collected in Serra Negra and others found on bryofloristic researches developed at different localities in Brazilian Southeastern Regions. The analyses of similarity were conducted using Sørensen index, cluster analysis of the areas (UPGMA algorithm), detrended correspondence (DCA) and canonical correspondence analysis (CCA). The results showed 218 collected specimens, distributed in 36 families and 92 species (57 mosses and 35 liverworts). The most representative mosses families were Leucobryaceae (10) and Sematophyllaceae (6), while for liverworts, they were Lejeuneaceae (10) and Plagiochilaceae (6). The cluster analysis showed a low similarity among the different areas tested. However, the dendrogram indicated a relationship between Serra Negra and those which have commom phytophysiognomical characteristics, such as rocky outcrops associated with quartzite soils and forest fragments above 1.500m altitud. The detrended correspondence analysis revealed the gradient formed by the inland areas and coastal areas. The canonical correspondence analysis corroborated the gradient observed by DCA. The CCA corroborated the gradient formed by DCA. The annual precipitation, maximum temperature, and distance from the ocean were the environmental factors that had more influence on the establishment of correlations between the analyzed areas.