PALEOCLIMATE AND ANTHROPOGENIC IMPACTS ON THE HOLOCENE VEGETATIONAL DYNAMICS IN THE NORTHERN NEOTROPICS: A PALYNOLOGICAL RECORD FROM LAKE IZABAL, EASTERN GUATEMALA

Amid growing concerns of diminishing tropical forests globally at alarming rates, palynology is an invaluable tool for exploring floral responses to climatic and human impacts on different time scales to quantify past changes and estimate future responses. This study is based on palynological data from a 7.6 m-long Lake Izabal core dated 9,500 cal yr BP based on extrapolation of ten radiocarbon dates of terrestrial wood fragments and one mollusk fragment in the sediments. Palynological analyses reveal interesting alternating paleovegetational patterns in the forest taxa (e.g., Fabaceae, Chloranthaceae, Bignoniaceae), as well as the presence of only trace amounts of disturbance taxa such as Poaceae, Asteraceae, and Amaranthaceae between 9,500 cal yr BP and 4,500 cal yr BP, and abundant disturbance taxa from 4,500 cal yr BP to the present. These patterns present the opportunity to assess forest responses at spatial and temporal scales spanning major climatic events, including the Holocene Thermal Maximum (8000 yr BP), Minoam warm period (3500 yr BP), Medieval Climate Anomaly (1000-700 yr BP), and the Little Ice Age (600-100 yr BP). In addition, anthropogenic impacts such as the Pre-Classic, Classic, Post-Classic Maya Civilization, the European occupation, and modern signals can be assessed. These findings are integrated with other northern Neotropics proxy records to ascertain the regional factors that drive the changes in the structure and composition of vegetation in time and space.