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Mangroves in Costa Rica

FIU Research Associate Dr. Edward Castañeda along with LSU Research Associate Dr. Andre Rovai and LSU Professor Dr. Robert Twilley have created a global model that sheds light on highly significant discrepancies in crucial mangrove ecosystem data.

Their research with the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program found that mangrove soil organic carbon (SOC) stocks have been underestimated by up to 50% in carbonate settings, and overestimated by up to 86% in deltaic coastlines. The study, published in the May issue of the Nature Climate Change Scientific Journal, also provided information for 57 other nations who, until now, did not have access to SOC data. Access to this valuable data will now allow these nations to develop or evaluate their blue carbon inventories.

“Global climate change agreements have stressed the importance of implementing carbon dioxide emission reduction strategies to foster conservation of terrestrial and blue carbon ecosystems and enhancement of forest carbon stocks. Our novel approach has improved our ability to generate more robust and accurate global estimates of mangrove SOC stocks that will provide countries with a more powerful tool to develop and assess their carbon footprint and inventories,” says Dr. Castañeda.

Castañeda, Rovai, Twilley, and colleagues from Brazil and Costa Rica approached the issue by empirically testing, for the first time, a conceptual framework that links geomorphological processes to distinct coastal environmental settings (CES). They assessed the role of environmental drivers that form distinct CES such as tides, river discharge, temperature, and rainfall, in defining SOC stocks. Using this framework, they were able to combine past global estimates of mangrove SOC data with additional literature and unpublished data to account for the global controls and variation in mangrove SOC stocks.

“While previous studies’ attempts to explain and predict global mangrove SOC have relied solely on climate variables or mean country-level statistics, we used a wholly distinct perspective that accounts for the role of coastal geomorphology in determining SOC stocks. Our model predicts mangrove SOC stocks compatible with values published for distinct CES”, says Dr. Rovai.

This novel approach resolved several crucial methodological aspects such as issues related to data quality, spatial representativeness, and model fine-tuning and, in doing so, it revealed striking discrepancies in previous estimates of global mangrove SOC stocks. With overestimates as high as 86% and underestimates as high as 50%, the significance of this new carbon inventory data cannot be overstated.

Given the number of countries lacking data in the neotropics, which shelter 30% of the world’s mangroves, and 54% of the global karstic coastlines, this study sheds light on the role of these regions as global blue carbon hotspots.

Read the full publication to learn more about this study.