Predation vs. Parasitism: A Case Study of Indigenous Co-Stewardship and Science Co-Production to Measure Temporal Shifts in Moose Mortality on Ancestral Lands of the Grand Portage Ojibwe

Maintaining subsistence species on hunting lands is essential to the food security and cultural preservation/flourishing of Indigenous peoples that rely on traditional foods. In northern North America, moose play a central role in subsistence, cultural, and stewardship practices but are declining in many parts of their range. Moose (Alces alces) in Minnesota are a threatened population that is integral to the lifeways of the Lake Superior Chippewa. This study, led by the Grand Portage Band, examines the shifting causes of adult moose mortality between 2010 and 2022 on the Grand Portage Indian Reservation and Voyageurs National Park. These efforts, rooted in principles of Indigenous sovereignty and co-stewardship, seek to sustain this vital species on ancestral lands. We observed that the relative importance of mortality causes varied over time, with Parelaphostrongylus tenuis and other health-related factors driving mortality during the initial decline period (2010–2014), while predation became a leading cause of mortality and quadrupled in probability during the stabilization period (2015–2022). Using a Bayesian framework, we integrated multiple contributing factors to accurately estimate cause-specific mortality probabilities and survival rates. The findings underscore the necessity for adaptive management strategies that address both parasitism and predation pressures to recover moose populations to pre-decline levels. Moreover, this study exemplifies how a long-term, Indigenous-led wildlife collaring and monitoring program is critical to capturing these dynamics and supporting the Grand Portage Band's ongoing stewardship. This research advances our understanding of moose mortality in a vulnerable population and reinforces the importance of Indigenous leadership in wildlife management and scientific co-production. By integrating traditional ecological knowledge found in Tribal-governmental planning documents with contemporary science led by their Natural Resources Management department, the Grand Portage Band is ensuring that moose remain a resilient and enduring part of their cultural and subsistence practices, thus contributing to the broader framework of Indigenous co-stewardship.