Impucas are seasonally inundated forest fragments located in the transition between the Cerrado and Amazonian Forest biomes. The objective of this study was to evaluate and to compare the vegetation structure of two impucas under different conservation status located at Araguaia State Park (AST), Mato Grosso State: non-altered vegetation structure (NA) (12º19'11.2"S and 50º44'15.6"W) and altered vegetation structure (AL) (12º09'04.2"S and 50º49'37"W). It was delimited five transects subdivided into 50 permanent plots of 10x20 m. All woody individuals with diameter at breast height > 5cm were sampled. The NA impuca presented 28 families, 42 genera and 45 species and AL impuca 22 families, 31 genera and 33 species. Total density, basal area and Shannon-Wiener's diversity index were 2,177 ind.ha-1, 35.23 m².ha-1 and 2.87 nats.ind-1 in NA impuca and 1,501 ind.ha-1, 25.16 m².ha-1 and 2.63 nats.ind-1in AL impuca, respectively. The most important species were Licania apetala, Calophyllum brasiliense, Ochthocosmus multiflorus, Mabea paniculata, Tachigali froesii and Xylopia sp. The AL impuca presented smaller floristic richness, species diversity, density and relative dominance in comparison with NA impuca, probably due the historic of disturbance and annual flooding. Floristic similarity (Sørensen) was high between ASP impucas. However, when they were compared with those of Tocantins and other Brazilian forests, the similarity was low, suggesting that impucas from Mato Grosso and Tocantins states presented their own floristic identity. This study contributes to the knowledge of the Brazilian ecotones, for elaboration of ASP management plan and for actions of recovery degraded impucas.
Phytosociology; Cerrado-Amazon Forest transition; Cerrado; Araguaia River Floodplain
