Palynological evidence of vegetation change during the last 10,000 years in the mid-valley of the Rio Doce, Brazil

Abstract

In order to reconstruct the vegetation history of the last 10.000 years, palynological analyses were carried out using 17 sedimentary samples of a core drilled in Parque Estadual do Rio Doce (PERD-MG). Twenty-one species of fern spores, 52 species of pollen grains and six species of fungi were identified. Phase 1 (10.375-9.350 cal. years BP) is characterized by a low concentration and diversity of pollen grains and is thus interpreted as a fluvial system with the presence of coarse-grained sediments. Phase 2 (9.062-8.195 cal. Years BP) is interpreted as a transition from a fluvial to lacustrine environment. Phase 3 (7.905-4.785 cal years BP) is characterized by increased trend of palynomorph concentration, highlighted by a high abundance and diversity of fern spores, which are indicative of a more a humid condition. The uppermost phase, Phase 4 (4.785-50 cal. Years AP), possessed a lower abundance of herbaceous flora, which is replaced by other vegetation groups (e.g. marsh, cerrado, Atlantic Forest). The uppermost sample represents the contemporary environment (~50 years), which is characterized as seasonally-flooded.