EVALUATING THE IMPACTS OF ENVIRONMENTAL CHANGE ON PLAYA FORM AND FUNCTION

Playa wetlands are ubiquitous features of arid and semi-arid regions and are particularly abundant on the High Plains of Kansas, Colorado, Oklahoma, New Mexico, and Texas in the central United States. In the State of Kansas alone, there are more than 22,000 playas, with the majority distributed throughout the High Plains region of western Kansas. Playas represent the most significant wetland resource for much of the High Plains and provide a host of essential functions including habitat, groundwater recharge, surface water storage, and water quality improvements.

Playas occupy the lowest elevational position within internally-drained watersheds, so water and wind- and water-transported material accumulates within playas. Playa function or health is directly related to sedimentation rates; if sedimentation rates are accelerated above geologic norms, sediment deposited within playas can reduce pore space and infiltration rates and decrease playa storage capacity and hydroperiod. This can result in reduced vegetative cover and habitat value, and, in extreme cases, completely fill-in playas. Linking sedimentation rates and processes to landscape-scale variables, such as land use, vegetation cover, and climate is essential to provide a robust model to examine and assess playa functions. While there is a growing body of research concerning the role of land use on sedimentation within playas, the impacts of climate change on playa sedimentation rates and processes have often been overlooked.

This research project establishes essential benchmark information about natural playa sedimentation processes and rates and determines how these processes and rates have responded to changes in land use, vegetative cover, and climate. Research directly assesses several questions related to sedimentation within playas, with emphasis placed on evaluating impacts to playa hydrological and ecological functions. By evaluating multiple playas that have undergone a range of land use changes, including efforts to protect and improve playa functions, the effectiveness of grassed buffers as a sediment management technique is directly assessed. By taking a landscape-scale approach, research also addresses questions related to habitat and landscape functions and conditions for both playas and the surrounding uplands.