Using a vegetation index to assess wetland condition in the Prairie Pothole Region of North America
Wetlands deliver a suite of ecosystem services to society, such as providing habitat for a variety of flora and fauna, improving downstream water quality, mitigating floods, supporting outdoor recreation, and storing carbon. Anthropogenic activities, such as wetland drainage for agriculture and urban development, have resulted in considerable wetland loss and degradation, diminishing the intrinsic value of wetland ecosystems worldwide. Protecting remaining wetlands and restoring degraded wetlands are common management practices to preserve and reclaim wetland benefits to society. Accordingly, methods for monitoring and assessing wetlands are required to evaluate their ecologic condition and the outcomes of restoration activities. Wetland plant communities reflect the ecologic condition of wetland systems; thus, plant community composition can be used to develop biotic indices for assessing wetland condition. Here, we present a novel methodology for conducting vegetation-based assessments, and provide a case study describing a wetland condition assessment of temporarily- and seasonally-ponded wetlands in the Prairie Pothole Region of the North American Great Plains. First, we describe a method for selecting wetlands to sample across broad geographic distributions using a spatially balanced statistical design. We then describe site assessment protocols, including vegetation survey methods, and how field data were applied to a vegetation index that categorized wetlands according to ecologic condition.