Floristic and structure of different strata in an urban Semideciduous Forest in Jatai, Goias state, Brazil

Comparative studies between different strata of forests in ecological succession are important to understand the forest dynamics. The study evaluated floristic, phytosociological and ecological aspects between the tree and regenerating strata of an urban fragment of semideciduous forest, in Jatai, Goias state. In the last decades, the vegetation that was typically savanna has become a forest. Trees (diameter at breast height, DBH >= 5 cm) were sampled in 12 permanent 200m(2) plots. In each of them, 25m(2) subplots were sampled for the regenerant stratum, which comprised individuals with DBH <5cm and height >= 1m. Regenerants had greater richness (31 species), with two more species than adults. There was low floristic and structural similarity between the strata, indicating a replacement of species over time. Shannon's diversity was significantly lower for the tree stratum (t test), since it presented low equability, with ecological dominance of few species. Both strata had a high proportion of pioneer species, when compared to other studies. Zoochory and species of forest environments were significantly more abundant in the regenerating stratum. The study revealed a fragment in a frank process of secondary succession and vulnerability in the face of anthropic pressures, with care regarding its conservation being important.