A influência de geadas nas fitofisionomias de cerrado no Triângulo Mineiro e Alto Paranaíba, Brasil

Abstract

The Cerrado covers about a fifth of Brazilian territory and presents a diversity of vegetation formations, such as forest, savannah and grassland formations. The distribution of formations and their phytophysiognomies is influenced by several factors, including climate and soil characteristics, in addition to events such as fire and herbivory. Another important factor is the occurrence of low temperatures and frost, whose long-term effects are little known. Frost can especially affect tree species in the Cerrado, impacting their geographic distribution and favoring open vegetation. This study aimed to analyze the relationship between the areas with the highest occurrence of frost and the distribution of Cerrado phytophysiognomies in the region of Triângulo Mineiro and Alto Paranaíba, in Minas Gerais. Six bioclimatic variables were used and a frost frequency index was created based on the days when the recorded temperature is below 3°C. The Kruskal-Wallis test and Dunn's posterior test were applied to verify the differences between groups of phytophysiognomies in relation to climatic variables and frequency of frosts. The results indicated that lower temperatures are more associated with areas of grassy-woody cerrado, which represent the Campo Limpo phytophysiognomies. Although frost is an infrequent phenomenon in the Cerrado regions, there is a significant influence on the composition and distribution of phytophysiognomies, favoring the presence of less woody vegetation. However, for the Campo Sujo, Campo de Murundus and Campo Rupestre phytophysiognomies, the results did not indicate a strong association with lower temperatures, suggesting that other variables play a more significant role in the occurrence of these phytophysiognomies.