Modern pollen spectra of the Cerrado vegetation in two national parks of Central Brazil, and implications for interpreting fossil pollen records.

Abstract

Twenty four surface sampleswere collected for palynological analysis fromdifferent environments in the Cerrado biome, which extends over a vast area in Central Brazil. These samples were used to investigate the relationship between vegetation and pollen spectra in the Cerrado and, thereby, contribute to amore precise interpretation of fossil pollen records from this region, particularly those collected on palm swamps. Pollen grains from the phytophysiognomy that surrounds the palm swamp generally occur in low percentages in surface samples, whereas local plants are very abundant in the pollen spectra. Although local taxa tend to predominate, two aspects of the landscapemay be reconstructed fromthe pollen spectra using numericalmethods: the local environment of the deposition site and the surrounding regional vegetation. Using PCA and dissimilarity coefficient analysis, a group of seventeen taxa and a group of fourteen arboreal taxa are proposed as those that provide improved results when investigating the local environment and regional vegetation, respectively. Because herbaceous taxa are very abundant in the palm swamps, an analysis of the content of arboreal taxa in the pollen spectra is more appropriate for reconstructing the openness of the regional vegetation.