Freshwater lagoon and coastal mangrove sediments as repositories of ecological change during the Holocene in the tropical lowlands of southern Belize

Keywords: fire history, pollen, Maya, Belize, paleoecology, climate, human-environment interactions
Session Type: Virtual Paper Abstract
Day: Tuesday
Session Start / End Time: 3/1/2022 02:00 PM (Eastern Time (US & Canada)) - 3/1/2022 03:20 PM (Eastern Time (US & Canada))
Room: Virtual 16

Abstract

Relatively little is known about Holocene-length, human-environment interactions in the tropical lowlands of southern Belize, mostly due to the lack of viable sites from which to extract paleoecological records. Because permanently wet freshwater lagoons are rare, we investigate the use of sediment cores from coastal mangrove ecosystems as suitable sites for reconstructing paleoenvironmental change in adjacent lowland environments. We report on high-resolution macroscopic charcoal, sedimentological, and stable isotope data for sediment cores taken from mangrove ecosystems in the Toledo District of southern Belize. From these reconstructions we infer both a record of environmental change and human impacts on the landscape. One mangrove site in particular, Pork and Doughboy Lagoon, shows clear evidence of fire starting ca. 7400 calendar years before present, with increasing fire throughout much of the Holocene. It also records a clear drop in fire activity ca. 1300 calendar years before present and little burning after that time. Because of the nature of sediment accumulation into mangroves ecosystems and its complicated relationship with sea-level rise, paleoecological reconstructions based on these records must be interpreted with some caution. However, the late Holocene drop in fire activity at Pork and Doughboy is consistent with the findings from a nearby freshwater lagoon, Agua Caliente. A new sediment core from this site provides a 3800 year-long charcoal and pollen record and illustrates drastic shifts in both fire activity and landscape cover in the last 2000 years. These sites provide an opportunity to further our understanding of Holocene human-environment interactions in southern Belize.