Holocene Charcoal Stratigraphy from Laguna Tortuguero, Puerto Rico, and the Timing of Human Arrival on the Island

Abstract

An 8 m sediment core from Laguna Tortuguero, Puerto Rico, provides a 7000 calendar year history of fire occurrence and sedimentation on the island's north coast. After c. 5300 cal-BP, microscopic charcoal particle concentration and influx increase abruptly, and values remain high for the next two millennia. Subsequent to c. 3200 cal-BP, fire occurrence gradually declines to more moderate levels. It seems likely that the mid-Holocene acceleration in fire frequency documented here may signal the onset of human disturbance of the landscape. Indirect detection of human arrival on oceanic islands from a sudden increase in stratigraphic charcoal may be a useful technique in other island contexts, although it is important to consider that wildfires can occur without a human ignition source.