Holocene Biogeography of Mangroves Along the Gulf of Mexico Coast: Past, Present, and Future

Louisiana State University, Baton Rouge LA

Investigators

Abstract

This research project will investigate past and present environmental conditions and mangrove distributions and provide predictive assessments of the future distributions of mangroves along the Gulf of Mexico coast. Mangrove expansion in the Gulf coastal region is a recent phenomenon, and the new insights from this project will provide a more comprehensive understanding of past environmental patterns and future expansion areas based on climatic fluctuations. The project will expand knowledge regarding how feedbacks from human-environment interactions affect wetland vegetation shifts in a region characterized by increasing environmental uncertainty. Project benefits to the broader community will include a better understanding of mangrove expansion to coastal area residents and communities and proactive water resources management planning by appropriate coastal federal and state agencies. The project will support science education in local schools through collaboration with the Coastal Roots Program at Louisiana State University. The investigators will participate in workshops with Louisiana school teachers and engage them in communicating scientific knowledge about environmental changes and mangrove expansion. Mangroves play a critical role in global carbon sequestration and provide many important ecosystem services. Long-term quantitative data on the distribution and abundance of mangroves along the U.S. Gulf Coast have been largely inadequate. This project will produce high-resolution multi-proxy stratigraphic records from four critical mangrove habitats to elucidate the changing distribution of all mangrove species along the Gulf Coast over the last 2,000 years. The investigators will focus on three core questions: (1) How has the distribution and abundance of mangroves changed in response to Holocene environmental and climatic variations along the U.S Gulf Coast? (2) Which environmental variables are most likely to be responsible for controlling the spatial distribution of mangroves in the U.S? (3) What will be the northern ranges of different mangrove species by the end of the 21st century? The investigators will use a combination of palynological, X-ray fluorescence, and loss-on-ignition analytic techniques and radiocarbon dating to reconstruct the Holocene vegetation changes and sedimentary history of mangrove habitats along the U.S Gulf Coast. Cellular automata modeling techniques will be used to predict the future ranges of different mangrove species by the end of the 21st century. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.