The Impact of Fire Changes in Mid-Late Holocene Sediments on a Karstic Lagoon in Quintana Roo, Mexico

Paleofires have increasingly gained relevance as a tool for understanding human occupation and eventually, anthropogenic climate change. Charcoal particles are a product of fire, which in turn results from either natural disturbances and/or anthropogenic practices, causing the land-use to change at local scale and consequently amplified to regional climate change. Here we study a five-meter-long, 6,000-year-old sedimentary sequence from La Encantada lagoon, southeastern Mexico. We analyzed charcoal and pollen content from the sedimentary sequence to reconstruct the environmental history of the region and analyze the potential deleterious effects of fires on specific vegetation taxa. Evidence showed anthropogenic occupation approximately at 3000 years near the lagoon, thus landscape became domesticated, and subsequently dominated by anthropogenic practices.

Our results showed the setting before and after humans became part of the system, and how vegetation responded to disturbances. This research evidence four main stages defined by charcoal trend throughout the record i) the bottom of the sedimentary sequence showed the fire as a product of natural disturbances, where vegetation turnover answers to environmental conditions and became relatively resilient ii) the second stage showed charcoal highest concentrations agreeing whit the occupation of Maya civilization iii) human influence prevail in this stage until Maya collapse (between 1300-1100 years), and iv) abandonment and recovery of land and vegetation after disturbance. We concluded that the characterization of fire regimes, and therefore charcoal analysis, is paramount to the understanding of the processes that lead to landscape domestication.