Ancient Maya Wetland Agriculture as a Lens for Long-term Resilience in Floodplains

The Rio Bravo river runs through a forested fluviokarst watershed in northwest Belize. A recent LiDAR survey revealed a landscape extremely modified by ancient Maya civilizations, with the remnants of expansive ancient canal and raised field networks running through the floodplain. While the Maya occupied and management the landscape for about 3000 years, there has been little disturbance in the floodplain that lies within the Rio Bravo Conservation and Management Area (RBCMA) for close to 1000 years. Just downstream of the RBCMA, however, has been subject to deforestation and conversion of land for intensive agriculture over the last 50 years. In this study, we used multispectral LiDAR to map ancient agriculture and model seasonal flooding, and Landsat to estimate modern deforestation rates. We then used excavations and multiproxy evidence such as radiocarbon dates, geochemistry, geomorphology, charcoal, and stable carbon isotopes to reconstruct the chronology and use of the Maya canal and raised fields, and natural floodplain aggradation before and after use. Our first results suggest a long history of human use of the floodplain and alternating period of wet and dry through time. But, most evidence suggests the raised fields were likely constructed very late in Maya civilization during and after an extended dry period in the region, agreeing with other smaller locations nearby. Additionally, a groundwater-fed creek very high in sulfate and calcium runs through the ancient system and into Rio Bravo, resulting in very high levels of gypsum in the soil that both ancient and modern farmers must cope with. The raised fields likely helped the ancient Maya adapt to water quality and quantity issues under a changing and highly variable landscape. We aim to gain insight into the resilience of long-term floodplain management over thousands of years under the Maya to use as a lens for evaluating the resilience of modern floodplain use under a rapidly changing climate.