Changes in prairie pothole region wetland plant communities and wetland conditions after fifty years
Many investigations into the effects of land management on wetland systems and their plant communities rely on contemporary data and relatively short periods of change. Historical data on wetland vegetation and water chemistry collected by Robert Stewart Sr. and Harold Kantrud in the Prairie Pothole Region (PPR) offer a unique opportunity to evaluate wetland changes after 50 years. They surveyed 136 wetlands in 3 areas (Mt. Moriah, Cottonwood Lake, and Crystal Springs) in Stutsman County, North Dakota during 1961–1966. Those data served as the foundation for the Stewart and Kantrud (1971) wetland classification system for glaciated prairie region. Since the 1960s, the PPR has experienced substantial intensification of agriculture and extreme climatic episodes, including a severe drought in 1989–1993. In 2013-2014, Ryann Cressey, graduate student at South Dakota State University, revisited 80 of those wetlands. Objectives of the study were to 1) assess and quantify changes in wetland plant communities, including assessment of changes in the on dominance and occurrence of invasive plant species (e.g.
Typha x glauca, Phalaris arundinacea); 2) assess and quantify temporal changes in wetland conditions (i.e., specific conductivity, water depth, wetland size, and cover type); and 3) evaluate the potential associations of land use practices, climate change, invasive plant species, and position of wetlands within study areas with changes in wetland plant communities and conditions. Ryann conducted early and late season vegetation surveys in each available wetland zone (e.g., wet meadow, shallow marsh) and measured water depths and specific conductivity in May, July, and September each year. Analyses and development of the final report are underway.