Vegetation patterns and the influence of rainfall after long-term fire suppression on a woody community of a Brazilian savanna

Abstract

We evaluated the structural and floristic characteristics of a Brazilian savanna fragment occupied by cerraddo (CD) and cerrado sensu stricto (CS) in response to the influence of rainfall and long-term fire suppression. We carried out floristic, phytosociological and remote sensing studies in a cerrado fragment located in Corumbatal (SP, Brazil) after 43 years of complete fire suppression. We surveyed 43 plots of 200 m(2) each (17 plots in CS and 26 plots in CD) and all individuals a >= 0.32 cm diameter measured at 30 cm from the ground were included in the sample. We calculated phytosociological parameters for each species and classified them in three ecological groups, namely savanna, generalist and forest species. The remote sensing analysis used aerial photographs and satellite images from 1962 to 2019 (i.e. 59 years). The structural study of community revealed high predominance of forest and generalist species when compared to savanna species. Non-linear correlation between CD expansion rates and total rainfall within the study period indicated a positive influence of the rainfall (R-2 = 0.42). Thus, our analysis indicated a tendency of a continuous and fast expansion of CD over areas of CS in the long-term absence of fire combined with periods of heavy rain.