Authors: Luke Blentlinger*, UTK Geography, Luis Guillermo Artavia, Escuela de Geografía, Universidad de Costa Rica, San Pedro de Montes de Oca, San José, Costa Rica, Sally P Horn, Department of Geography, University of Tennessee, Knoxville, Tennessee, Chad S Lane, Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, North Carolina
Topics: Paleoenvironmental Change, Biogeography, Physical Geography
Keywords: Lake sediments, savannas, stable isotopes, palynology
Session Type: Poster
Presentation File: No File Uploaded
The factors that determine boundaries between savanna and forest in Central America and whether modern savannas predate European impact have generated debate. Lake sediments are natural archives of environmental information that can be analyzed to learn about past environmental change. Studying lake sediments can better our understanding of the environmental history of savanna ecosystems. This study investigates past environmental change in the grass savannas of the El General Valley, Costa Rica. We present a multi-proxy study of lake sediment cores from two shallow lakes in Buenos Aires, Costa Rica. We analyzed pollen grains and stable carbon isotopes to reconstruct changes in vegetation over time, and tallied charcoal fragments to chart changes in fire occurrence. We found that macroscopic pieces of charcoal are in low abundance through the profiles, with higher concentrations in recent sediments. Pollen analysis shows varying levels of grass pollen from savanna vegetation and microscopic charcoal from fires.