Metapopulation viability analyses of woodland caribou in the Lake Superior range

Abstract

Woodland caribou populations in the Lake Superior range have deteriorated. The caribou’s decline follows industry growth since the 1900s. Islands like those in Slate Islands Provincial Park, Michipicoten Island and Caribou Island offer periods of escape from wolves, the main predators of caribou. Minute mainland populations exist because of translocations conducted in the early 1980s and late 2010s with A.T. Bergerud, and later Gord Eason at the head. Together with the island populations, the safest and most common areas of translocations, the mainland connects what can be considered a metapopulation. Population viability analyses (PVAs), run on Vortex10, were conducted to determine ways of creating a stable metapopulation with consideration given to future arrivals of wolves and future translocations to the Lake Superior islands. The probability of icing events for caribou dispersion were factored into the PVAs. Wolf appearance on islands has been the chronic limiting factor of caribou abundance. Allowing no translocations created a high probability of functional extinction. Specific translocation starting in the present and continuing until 10 years created the highest likelihood of persistence of the metapopulation. The Slate, Michipicoten, and Caribou islands are crucial to metapopulation persistence. Further recovery of the woodland caribou populations in the Lake Superior range should view translocations as a beneficial management approach.