FCE researchers have found significant spatial differences in mangrove productivity; from riverine mangrove forests with productivity rates similar to tropical rain forests to low structure scrub mangroves that grow in nutrient-poor environments. Mangrove forests growth and survival are greatly influenced by the impacts and legacies of hurricanes, sea-level rise and human impacts along coastal areas.
- Key Findings
Mangrove forests in the Florida Everglades form an ecotone, which is a critical link between freshwater marshes and the marine environments of Florida Bay and the Gulf of Mexico. These forested wetlands provide shoreline protection against storms, "nurseries" for shrimp, fish, and crabs, as well as habitat for several endangered and threatened species such as the American crocodile.
Our researchers have made important contributions to our understanding of mangrove forest structure and productivity trends. We installed - and still operate - the first eddy covariance tower in a riverine tall mangrove forest in 2003 to measure the net ecosystem exchange of carbon dioxide between the mangrove forest and the atmosphere. Mangroves remove relatively large amounts (about 1000 g of carbon per m2 per year) of carbon dioxide from the atmosphere compared to other forest types, such as tropical rainforests. Temporal and spatial mangrove forest productivity and structure differences are largely controlled by large-scale disturbances, such as tropical cyclones, which can defoliate and kill mangrove trees. Recovery rates vary with the magnitude of disturbance, but can be accelerated by delivery of nutrients in water and soils from associated storm surge.
We also have a network of sediment elevation tables (SETs) that measure accretion and relative elevation rates in coastal wetlands. Results from these devices are used in predictive modeling efforts to project magnitudes and consequences of sea-level rise. Further, we are collaborating with the Luquillo and the Mexican LTER programs to establish a Caribbean Hurricane Research Network (CHURN) to facilitate cross-site, collaborative research on the ecological and socio-economic factors influencing hurricane impacts on the greater Caribbean coastal regions.
- ResultsSeasonal patterns in net ecosystem carbon exchange (NEE) for the mangrove forest located in the western Everglades. The NEE values were determined from flux tower measurements. The carbon content in leaf litter production is also shown. Despite their harsh habitat, mangroves remove from the atmosphere substantial amounts of carbon, with net assimilation exceeding 1000 grams of carbon per m^2 per year. We now know the environmental and physiological controls on mangrove ecosystems.
Credit: J. Barr, J. Fuentes, V. Engel, R. Rivera-Monroy, and E. Castañeda-Moya
- Related Publications
Barr, J.G., V. Engel, J.D. Fuentes, J.C. Zieman, T.L. O'Halloran, T.J. Smith, G. Anderson. 2010. Controls on mangrove forest-atmosphere carbon dioxide exchanges in western Everglades National Park. Journal of Geophysical Research 115: G02020.
Castaneda-Moya, E., R.R. Twilley, V.H. Rivera-Monroy, K. Zhang, S.E. Davis, M.S. Ross. 2010. Sediment and nutrient deposition associated with Hurricane Wilma in mangroves of the Florida Coastal Everglades. Estuaries and Coasts 33: 45-58.
Smith, T.J., G. Anderson, K. Balentine, G. Tiling, G.A. Ward, K. Whelan. 2009. Cumulative impacts of hurricanes on Florida mangrove ecosystems: Sediment deposition, storm surges and vegetation. Wetlands 29: 24-34.