The cerrado biodiversity is being seriously threatened by deforestation, since many of its species present restrict geographic distribution. Because of its central position in South American continent, the cerrado has extensive borders with other vegetation types, including swamp forests. We aimed at: 1) knowing the flora and describing the community of shrubs and trees of a cerradão (savanna woodland) and its transition to a swamp forest in Brotas municipality, SE Brazil; 2) investigating the floristic similarity among other cerrado areas in São Paulo State. We found 125 species of 91 genera and 49 families in the fragment surveyed. Myrtaceae and Leguminosae had the highest species richness, a pattern frequently found in other areas of cerrado in São Paulo State. However, only in Brotas, Lauraceae and Euphorbiaceae had a high species richness. We sampled a total of 3,787 individuals (DSH > 3 cm) in one hectare and estimated H' = 3,378 nats.individual¹ . The species with highest Importance Value Indices were Xylopia aromatica, Vochysia tucanorum, Ocotea pulchella, Gochnatia polymorpha, and Myrcia albo-tomentosa. There was no significant correlation between the floristic similarity and the geographical distance among the 10 cerrado areas compared, due the high proportion of common species. The high proportion of common species among cerrado areas in São Paulo State corroborates the results of other authors, who found that it is located on a center of diversity, whose floristic composition is different from the other Cerrado's diversity centers in Brazil.
cerrado; community structure; floristic composition; swamp forest; floristic similarity
