A 4700-Year Record of Lake Evolution and Fire History for Laguna Limon, Dominican Republic

Abstract

Fire is a primary driver of environmental change that can originate from natural or human ignition. Macroscopic charcoal (>125 "m) deposited into lake sediment is a record of a local fire event, whereas microscopic charcoal indicates fire activity on a broad landscape scale. Patterns of charcoal deposition may shed light on both human activities and climate history over long-time scales. Whether lowland Caribbean forests have experienced natural fire regimes over the long-term is unknown. Laguna Limón is a little-studied, large, freshwater lake on the northeastern coast of the Dominican Republic. We extracted four overlapping sediment cores totaling 315 cm in depth, and conducted analysis of macroscopic charcoal (2-cm), microscopic charcoal (16-cm), and loss-on-ignition (1-cm) to examine the long-term fire and environmental history of the area. Loss-on-ignition data established that the lake has only recently become organic rich, and was likely open to the sea as a low energy bay until 1400 Cal. Yr BP. The lake existed briefly as a wetland before transitioning to the modern freshwater lake 1200 Cal. Yr BP. Macroscopic charcoal was most abundant in the freshwater section of the core while microscopic charcoal peaked near the bottom of the core, and aligns well with other regional microscopic charcoal records. Overall the charcoal record reflects a combination of climatic and anthropogenic related charcoal deposition suggesting that fire has played an active role in the environmental history Laguna Limón.