Coastal Wetland Hydrologic Resilience to Climatic Disturbances: Concept, Quantification, and Threshold Response

Climate change, the rising air temperature and changes in the intensity and frequency of rainfall, and sea level rise (SLR), represents one of the most important threats to coastal wetlands that have numerous ecosystem services from erosion and water quality control to wildlife habitat. Climate change-induced disturbances affect the sustainability of coastal wetland ecosystems mainly through altering their hydrologic functions. However, how to assess wetland hydrological resilience, the ability of wetland hydrology to recover from climate disturbances remain challenging. This chapter first summarizes current knowledge of the coastal hydrologic cycle and the influence of climate change on the coastal hydrologic cycle. Then, we define hydrologic resilience, identify the hydrologic conditions, and quantify the hydrologic resilience. Last, we present a case study on bottomland hardwood forests along the Atlantic coast. We applied a physically based watershed-scale wetland hydrological model (PIHM-Wetland) to the coastal wetland system and quantified the hydrologic resilience in response to climate extreme events during the recent 20 years using a distributed-system approach. The case study shows that the metrics to quantify hydrologic resilience to drought, extreme rainfall events, and sea level rise are effective and may be appliable to other similar regions.