Doctoral Dissertation Improvement Award: Effect of Sea Level Variation of Fuelwood Sustainability

Mangroves have long been important to meet the fuelwood needs of people living along tropical coastlines. In turn, mangrove forests are critically important to coastal ecosystem health. This project examines long-term mangrove forest composition based on data collected from archaeological wood samples from South Florida. It makes use of fuelwood residues, a rarely exploited data source, to investigate wood selection and management strategies along with their secondary effects on local forests. A key question being addressed is resource sustainability, as evidenced in changing wood availability. Moreover, the time-transgressive trends in wood species and their growth cycles documented by this research will help to establish a long-term record of forest health and resilience that can be used not only to contextualize the magnitude of recent and ongoing changes, but to aid in understanding legacy effects from activities such as thinning and habitat reduction, as well as from natural disasters (e.g., hurricanes) and environmental change. Although coastal forests have long been recognized as providing valuable ecological services, they are endangered worldwide. The importance of coastal mangrove communities to tropical coastal and marine environments and thus also, to human inhabitants and local economies is difficult to exaggerate. These forests provide habitat and breeding grounds for many marine organisms, thus supporting several fisheries. Mangrove forests buffer coastlines against hurricanes and inhibit terrestrial runoff further contributing to ecosystem health and protection. The use of archaeological wood charcoal to establish an historical timeline of mangrove forest presence and growth characteristics will provide a valuable context for establishing modern management guidelines and regulations. To that end, this project is working in concert with local conservation organizations and state agencies; each will benefit through cooperation and data sharing. Furthermore, the research contributes to the education and training of both graduate and undergraduate students, as well as local residents and project volunteers.

One aspect of the research is testing alternative hypotheses generated from prior study of proxy records of sea-level variability over time. Sea level and water quality have direct effects on the survival and biogeography of mangrove communities. While this project is focused primarily on Calusa Island, the work is part of a larger endeavor that examines ancient human-forest resource interactions regionally. The wood charcoal analyzed here derives from an eroding archaeological shell mound and will aid in the creation of a long-term baseline of forest resilience as influenced by human activity, natural disturbances, and climate change in Southwest Florida's coastal estuary system. The research will also initiate an archaeological site monitoring project that will track rates of shoreline erosion and impacts on both the archaeological deposits and the modern forest/flora. Further, the exploratory excavations will aid in documenting a regionally, rare Archaic Period occupation and will provide preliminary data that will enable future conservation work or salvage excavations at the site. Finally, this project will collect exploratory pollen data to evaluate their potential for use as an independent environmental proxy on the influence of high-intensity, natural disturbance events, such as hurricanes, among the mangroves.