Characterizing the Climate-Driven Collapses and Expansions of Wetland Habitats with a Fully Integrated Surface–Subsurface Hydrologic Model

Links between climatic forcing and wetland habitats can be conceptualized using a graph-theoretical approach, which treats wetlands as nodes to map habitat connectivity and to define habitat networks for ecological analysis. The first and most crucial step in creating a network model, however, is to characterize the dynamic behaviors of the nodes, i.e., the occurrence of wetlands with ponded water, or water bodies. For the first time, this study applies a 3-D, fully integrated surface and subsurface flow model, HydroGeoSphere (HGS), to simulate the hydrologic dynamics of wetlands in the Prairie Pothole Region (PPR) and to characterize the resulting habitat networks as a function of climate variability. Results show HGS is able to simulate water movement in both surface and subsurface domains and capture “fill-spill” and coalescence/disaggregation behaviors of wetlands as they respond to wet and dry climatic conditions. Our simulations for a small representative subarea of the PPR show wetland networks in the PPR could easily shrink, degrade, or even collapse when the climate becomes drier. This study demonstrates the potential in applying sophisticated hydrologic models to solve critical ecological problems and the practical implications for water-resources management, conservation planning and decision-making in the PPR.