The Prairie Pothole Region (PPR) spans ~170 million acres in the northern Great Plains. The region is characterized by mixed-grass and tallgrass prairies, composed of native cool- season (C3) and warm-season (C4) grasses, interspersed with abundant wetlands or “potholes.” To safeguard biodiversity and maintain wildlife habitat, grassland conservation is a management priority on the nearly 1 million acres of National Wildlife Refuge System lands in the region.