Modeling current and historic habitat for Canada lynx ( Lynx canadensis) in the Upper Peninsula of Michigan

In the ruling to list Canada lynx (Lynx canadensis ) as a federally threatened species, the US Fish and Wildlife Service identified the Great Lakes region as an area of concern. While there is no current evidence of a resident population in the Upper Peninsula (UP) of Michigan, trapping and track records over the past century suggest the area was periodically invaded by lynx during population eruptions in Canada. My objectives were to quantify past and present forest conditions in the UP for lynx habitat potential, and estimate changes in habitat connectivity between Canada and the UP. I used a spatially explicit, landscape-level habitat model that required multiple layers of spatial data compiled in a GIS to describe lynx habitat components. Forest inventory plots were used to provide detailed stand attribute information. The historical range of variability in presettlement forest conditions was simulated with the landscape age-class demographics simulator (LADS). Outputs from the model indicated that potential habitat has become more widespread under current conditions than that which existed during the presettlement era. Foraging quality has increased in many areas across the UP, but remains low throughout. Non-habitat interspersion is limiting under current conditions and has increased dramatically from that of presettlement in the eastern UP. This increase has resulted in lower habitat quality and decreased connectivity of habitat in the eastern UP. The establishment of a resident lynx population in the UP is questionable.