Fire History in Guyanese Peatlands: Insights from Charcoal and Radiocarbon Data

Tropical peatlands are one of the most carbon-dense ecosystems on Earth. However, their long-term resilience to climate and environmental changes, including fire events, remains poorly understood and is understudied compared to boreal and temperate peatlands. This study represents the first palaeoenvironmental research conducted on the peatlands of Guyana, addressing a critical knowledge gap in understanding the long-term dynamics of tropical peatland ecosystems in this region. Further knowledge of these dynamics is essential for understanding the vulnerability of these ecosystems in the face of climate change and increasing anthropogenic disturbances.

This study investigates the fire history of peatlands in Guyana by analysing charcoal and radiocarbon data from two peat cores. Fieldwork involved the collection of cores from various sites in Guyana, representing different hydrological and vegetation conditions. Charcoal analysis is being conducted to quantify fire events, identifying both their frequency and intensity over time. Radiocarbon dating has been used to establish basal dates of peat accumulation in the two cores, of 970 and 6450 years. Higher resolution radiocarbon dating is being used to establish a chronological framework for fire episodes, enabling the reconstruction of long-term fire history. Complementary analyses, including organic matter characterisation through thermogravimetric analysis, provide additional context on how fire events may have influenced peat composition and carbon storage. 

Preliminary observations suggest the presence of charcoal-rich layers within the peat cores, indicating continued fire activity over time with varying intensity. These layers vary between the two sites, suggesting localised differences in fire history. These are potentially driven by differing vegetation types, hydrological conditions, or human influence. By the time of conference, we anticipate presenting a timeline of fire episodes, linked to rates of peat accumulation and potential environmental drivers such as shifts in climate or human land use.

This research provides critical insights into the role of fire in tropical peatland development, offering a unique perspective on the interactions between fire, carbon accumulation, and ecosystem dynamics in this under-researched region. The findings have significant implications for the conservation and management of tropical peatlands, emphasising the need to consider historical fire regimes when predicting future ecosystem resilience/vulnerability. Overall, this study contributes to the broader understanding of tropical peatlands as dynamic carbon reservoirs that are increasingly threatened by global environmental change.