Efeito do fogo sobre uma comunidade vegetal de cerrado sentido restrito

Abstract

Fires are historically known in Brazilian Cerrado, and it is a primordial factor that modulate plant communitie structure and composition. The ability to resist to fire and recover from its effects is inherent to every plant. Thus, the main objectives of this article are as follow; 1- To evaluate the phytosociological structure of a post-fire sensu stricto Brazilian Cerrado, 2 - To evaluate the effects of fire upon its arboreal components, and 3 - To evaluate the loss of biomass and the mortality rates in the plant communities and species in the aftermath of a fire. This study has been conducted in the Estação Ecológica do Panga both before and 50 days after the fire. Twelve permanent and contiguous plots have been established, measuring 20 x 20 m2 each one. The first sampling took place pre-fire, and every individual whose CAS (circumference at ground level), was superior to 15 cm were properly measured and identified. In the second sampling, the survival and mortality of all individuals was assessed. 1101 arboreal individuals (2294 ind ha-1), among 74 species and 34 families were sampled. After the fire, 82 individuals (7,44%) perished. The species diversity has presented Shannon (H’) diversity index values of 3,19 nats ind-1. About 10% of the sampled individuals are representative of forests and are distributed among 18 species. The species Myrcia splendens, Vochysia tucanorum, Ocotea corymbosa and Tachigali vulgaris, when combined, represent 50% of the whole. The mortality rate within the 96 individuals typical of forest areas represents 15% of the whole, while, among the 996 individuals typical of savanna areas, only 6% perished, which is indicative that forest species are more sensitive to fire than savanna species.