ABSTRACT
This study aimed to describe the tree structure and floristic composition of two seasonally flooded forests at Poço das Antas Biological Reserve and to compare these forests to other Atlantic Forest types in the region. Six plots of 30 m x 20 m were set up in each fragment. All trees (DBH ≥ 10 cm) were sampled. The fragments (ARI and CM) were structurally very similar. A total of 628 trees were sampled being distributed within 16 families and 31 species, with strong dominance of flooding tolerant heliophilous trees, such as Calophyllum brasiliense, Symphonia globulifera (Clusiaceae) and Tabebuia cassinoides (Bignoniaceae). This three species together accounted for 73% of cover value in ARI and 67% in CM. The species diversity (H' = 1,75 and 1,99, respectively to ARI and CM) can be considered to be within the values found for swamp forests in Southeastern Brazil. Both fragments showed high floristic similarity due to dominance of heliophilous trees. However, species similarity was low in comparison to adjacent well-drained Atlantic Forest. Soil flooding apparently was the major regulator factor of the floristic composition in this vegetation.
Key words:
Swamp forest; fragmentation; lowland Atlantic Forest; phytosociology