Potential distribution and connectivity for recolonizing cougars in the Great Lakes region, USA

Abstract

Cougars (Puma concolor) have lost substantial portions of their historical range yet increased sightings suggest potential for re-establishment in some regions; greater understanding of potential distribution and connectivity is necessary to make sound management and policy decisions. Specifically, the Great Lakes region of the USA will likely be an important area for cougar range expansion into the Midwest and Eastern USA. We used verified cougar observations to model and predict potential distribution and connectivity in the Great Lakes region. We compiled all confirmed observations of cougars from Michigan, Minnesota, and Wisconsin (2010–2020); which resulted in 180 reports (154 images/videos, 20 signs, 6 mortalities). We developed an ensemble distribution model (1 km res) based on three machine learning methods. We used weighted cost-distances to identify linkages between core areas and circuit theory to model overall connectivity potential. We calculated selection ratios for land covers (30 m res) at fine and coarse scales. The ensemble distribution model had good performance (ROC of 0.94). Suitability was positively associated with increasing vegetation structure, lower distance to natural cover, and mid-high terrain ruggedness. Forest covers were always selected for regardless of scale, and human development was avoided only at the coarser scale. We identified 191 core patches and 362 linkages connecting them; only 50.1% of them were located within legally protected areas. We identified high regional connectivity in a generally west-east direction. Successful conservation of large carnivores like cougars will depend on conserving not only habitat patches and linkages but also efforts to facilitate long-term coexistence.