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Sampling is conducted at 15 mangrove creeks in two drainages: Rookery Branch and the North, Roberts, and Watson rivers. Electrofishing is used to target large-bodied predatory species. At each creek, we systematically sample, three 100 meter long sections of creek bank by electrofishing (0-100m, 200-300m, and 400-500m). Each electrofishing bout lasts five minutes (pedal time). Electrofishing is an effective method for sampling large fishes in freshwater habitats, and eletrofishing catch per unit effort (CPUE) provides a reliable index of fish abundance. For all bouts, electrofishing power is standardized to 1500 watts according to the ambient temperature and conductivity conditions. Because creek width is considerably greater than the electric field generated by the electrofisher, a left or right bank was randomly selected for each bout. Folling USGS-NAWQA guidelines, all electrofishing is conducted using intermittent application of electrical current to prevent fish from fleeing deep beneath the mangroves. All fish captured are placed in a holding tank, identified, measured (to the nearest 1-mm standard or total length), weighed (if necessary), and released after full recovery. Only non-indigenous species are saved and preserved in 10 percent formalin to be returned to the laboratory for processing. During each sampling event, we use a YSI 85 unit to record physico-chemical parameters (water temperature, specific conductance/salinity, and dissolved oxygen) at the beginning of each electrofishing bout. Water clarity and bottom type are measured with a measuring stick and turbidity with an electronic turbidity meter.

Our FCE I research focused on understanding how dissolved organic matter from upstream oligotrophic marshes interacts with a marine source of phosphorus (P), the limiting nutrient, to control estuarine productivity where these two influences meet-in the oligohaline ecotone. This dynamic is affected by the interaction of local ecological processes and landscape-scale drivers (hydrologic, climatological, and human). During FCE I, our ideas about how these "upside-down" estuaries (Childers et al. 2006) function has evolved, and we have modified our central theme to reflect this new understanding. Our focus in FCE II will be even more strongly on the oligohaline ecotone region of our experimental transects. For FCE II, our overarching theme is: In the coastal Everglades landscape, population and ecosystem-level dynamics are controlled by the relative importance of water source, water residence time, and local biotic processes. This phenomenon is best exemplified in the oligohaline ecotone, where these 3 factors interact most strongly and vary over many [temporal and spatial] scales.Hypothesis 1: Increasing inputs of fresh water will enhance oligotrophy in nutrient-poor coastal systems, as long as the inflowing water has low nutrient content; this dynamic will be most pronounced in the oligohaline ecotone. Hypothesis 2: An increase in freshwater inflow will increase the physical transport of detrital organic matter to the oligohaline ecotone, which will enhance estuarine productivity. The quality of these allochthonous detrital inputs will be controlled by upstream ecological processes. Hypothesis 3: Water residence time, groundwater inputs, and tidal energy interact with climatic and disturbance regimes to modify ecological pattern and process in oligotrophic estuaries; this dynamic will be most pronounced in the oligohaline ecotone. Childers, D.L., J.N. Boyer, S.E. Davis, C.J. Madden, D.T. Rudnick, and F.H. Sklar, 2006. Relating precipitation and water management to nutrient concentration patterns in the oligotrophic "upside down" estuaries of the Florida Everglades. Limnology and Oceanography, 51(1): 602-616.

National Science Foundation under Grant # 9910514 and #0620409

Coastal ecosystems are being modified at unprecedented rates through interacting pressures of global climate change and rapid human population growth, impacting natural coastal resources and the services they provide. Located at the base of the shallow-sloping Florida peninsula, the Everglades wilderness and 6 million human residents are exceptionally exposed to both pressures. Further, freshwater drainage has accelerated saltwater intrusion over land and into the porous limestone aquifer, resulting in coastal ecosystem transgression and seasonal residential freshwater shortages. The unprecedented landscape-scale Everglades restoration process is expected to reverse some of these trends. However, it is not clear how uncertainties about climate change prognoses and their impacts (e.g., sea level rise (SLR), changes in storm activity or severity, and climate drivers of freshwater availability) may influence human activities (e.g., population growth, resource use, land-use change), and how their interaction will affect the restoration process that is already steeped in conflict. The Florida Coastal Everglades Long-Term Ecological Research (FCE LTER) program is dedicated to long-term coupled biophysical and cultural studies that expose and unravel complex feedbacks that generate distinctive patterns and processes in vulnerable coastal ecosystems. The overarching theme of FCE research is: In the coastal Everglades, climate change and resource management decisions interact to influence freshwater availability, ecosystem dynamics, and the value and utilization of ecosystem services by people. Because they are highly sensitive to the balance of freshwater and marine influences, coastal wetlands of the Florida Everglades provide an ideal system to examine how socio-ecological systems respond to and mitigate the effects of climate change and freshwater allocation decisions. The trans-disciplinary science conducted by the large FCE research team is revealing how estuary hydrodynamics and biogeochemistry may tilt on a fulcrum defined by the magnitude by which coastal pressures (SRL, storms) are mitigated by freshwater flows. We employ a socio-ecological framework to address how climate change interacts with political decisions to determine the sustainability of interconnected human-natural systems. In FCE I, we discovered how coastal nutrient supplies create an unusual “upside-down” productivity gradient in karstic estuaries. FCE II research used growing long-term datasets to reveal the sensitivity of this gradient to changes in hydrodynamics, nutrient availability, and salinity. In FCE III, we will use South Florida as an exemplary system for understanding how and why socio-ecological systems resist, adapt to, or mitigate the effects of climate change on ecosystem sustainability. We will examine how decisions about freshwater delivery to the Everglades influence -and are influenced by - the impact of SLR in this especially vulnerable landscape. Biophysical studies will focus on how this balance of fresh and marine sources influences biogeochemical cycling, primary production, organic matter dynamics, and trophic dynamics, to drive carbon gains and losses. We expand our spatio-temporal domain by employing powerful long-term datasets and experiments to determine legacies of past interactions, and to constrain models that will help guide a sustainable future for the FCE.

National Science Foundation under Grant # 9910514, #0620409 and DEB-1237517