ABSTRACT
Aiming to contribute to the better understanding of this kind of Pantanal forest, the results from a floristic-structural survey performed in a 1ha plot commonly classified as "Acuri Forest", located at RPPN SESC Pantanal (Municipality of Barão de Melgaço - MT, Brazil - 16º45'S; 56º15'W) are presented. The floristic data were obtained from systematic collection of botanical material on the studied area and surroundings. The structural data were obtained from a one ha plot, divided into 100 contiguous sub-plots (10m x 10m). Inside these sub-plots, all arboreal individuals with diameter at breast high equal or greater than 5.0 cm, including palms, were identified, measured and mapped, using a coordinate system. 1224 individual ha-1 were sampled, representing 44 species, 43genus and 27 families; diversity index H'= 1.613 (var. 0.003514). The highest diversity families were Fabaceae (9 spp.), Sapindaceae e Anacardiaceae (3 spp. each), Bignoniaceae, Malvaceae, Moraceae e Rubiaceae (2 spp. each). Among the sampled species, 39 % were evergreen; 32 % semideciduous and 29% deciduous. Considering the tree individuals total (n = 440), 51 % were decíduos; 23% semideciduous and 26% evergreen. Attalea phalerata was the species with the highest structural value (VI= 121.62), due to its high density (64% of the total sampled individuals), frequency (100%) e and very high basal area (74.10 m2 ha-1). On second level of importance were Anadenanthera colubrina, Triplaris americana and Phyllostylon rhamnoide (VI= 35.41; 28.51; 18.5 respectively). The studied area was identified as very peculiar comparatively with other Seasonal Forest areas, especially because the Attalea phalerata massive density and absence of Myrtaceae representatives. The high representation of pioneer species in association with high density of individuals within this successional category reinforces that Mata com Acuri represents an early successional stage or a transitional stage. Based on the great percentage of deciduous and semi-deciduous species recorded for the area of study, it was classified as being representative of Deciduous Forest.
Keywords:
Seasonal Deciduous Alluvial Forest; floristic; phytosociology
