For millennia, Indigenous people created more productive, healthy ecosystems by modifying them with fire, and by altering the movements of important wildlife species such as bison (Bison bison), as part of Traditional Ecological Knowledge (TEK). Since 2006, I have been partnering with Tribal Nations and federal managers in Canada and the US on the Northern Great Plains to measure grassland ecological responses to prescribed fires and other adaptive management actions based on TEK. I will discuss how our collaboration is informing federal and Tribal management of grasslands and advancing sovereignty rights for Tribes.