Carbon Stocks in the Wetlands of a Tropical Near-Coastal Lake: A Comparison of Estimation Methods

Wetlands are among the most efficient terrestrial ecosystems for long-term carbon sequestration; however, information on carbon stocks in karst-derived tropical freshwater wetlands remains scarce. We estimated carbon stocks in above-ground and below-ground components of vegetation types associated with the Bacalar lagoon system in southeastern Mexico. We compared different carbon estimation methodologies to assess how methodological choices affect carbon stock estimates at the sample’s sites. Five vegetation types were studied; above-ground biomass was estimated using multiple allometric equations, which were compared in terms of relative variability using coefficients of variation. Below-ground carbon was quantified from root biomass and soil organic carbon using the loss-on-ignition (LOI) and Dumas methods. Gallery forest had the highest above-ground carbon stocks due to larger tree sizes, while mangroves (included petenes) stored greater amounts of below-ground carbon, reflecting the influence of hydrology, clay-rich substrates, and the accumulation of organic matter. The LOI based estimates were higher than Dumas, although both approaches showed similar patterns and high agreement following cross-validation. Our results show that vegetation type, substrate characteristics, and methodological choices significantly influence estimates of carbon stocks. Karst wetlands are important carbon reservoirs, and their conservation contributes to the mitigation of regional climate change.