Modeling the potential impacts of climate change on the water table level of selected forested wetlands in the southeastern United States
The southeastern United States hosts extensive forested wetlands, providing ecosystem services including carbon sequestration, water quality improvement, ground- water recharge, and wildlife habitat. However, these wet- land ecosystems are dependent on local climate and hydrol- ogy, and are therefore at risk due to climate and land use change. This study develops site-specific empirical hydro- logic models for five forested wetlands with different char- acteristics by analyzing long-term observed meteorological and hydrological data. These wetlands represent typical cy- press ponds/swamps, Carolina bays, pine flatwoods, drained pocosins, and natural bottomland hardwood ecosystems. The validated empirical models are then applied at each wetland to predict future water table changes using climate projec- tions from 20 general circulation models (GCMs) participat- ing in Coupled Model Inter-comparison Project 5 (CMIP5) under the Representative Concentration Pathways (RCPs) 4.5 and 8.5 scenarios. We show that combined future changes in precipitation and potential evapotranspiration would sig- nificantly alter wetland hydrology including groundwater dy- namics by the end of the 21st century. Compared to the his- torical period, all five wetlands are predicted to become drier over time. The mean water table depth is predicted to drop by 4 to 22 cm in response to the decrease in water availabil- ity (i.e., precipitation minus potential evapotranspiration) by the year 2100. Among the five examined wetlands, the de- pressional wetland in hot and humid Florida appears to be most vulnerable to future climate change. This study pro- vides quantitative information on the potential magnitude of wetland hydrological response to future climate change in typical forested wetlands in the southeastern US.
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