Health assessment of two reintroduced populations of American martens (Martes americana) in Michigan

The American marten (Martes americana) was extirpated from Michigan during the early-20th century due to loss of vast areas of mature conifer forest and unregulated trapping. The species was reintroduced into the Upper Peninsula (UP) and Northern Lower Peninsula (NLP) during the mid-20th century. While the American marten population in the UP has grown and is doing well, the population in the NLP has been less successful. The reasons for the limited success of the NLP population are unknown, but may include lack of suitable habitat, limited reproductive success, poor genetic diversity, disease, or negative environmental impacts. American marten were live-trapped from 2011-2015 in the Manistee National Forest (NLP) and the Hiawatha National Forest (UP) of Michigan concurrent with a large-scale habitat and genetic study to evaluate the health of these two reintroduced populations. Parameters assessed included blood chemistry and complete blood counts, fecal parasite exams, hair stable isotope ratios, and serological evidence of disease. In addition, carcasses from trapper-harvested American marten in the UP were collected during 2012-2014 for hair stable isotope ratios and Toxoplasma serology. This is the first report of an assessment of general health and exposure to pathogens in American marten in Michigan and will be used to inform future management decisions including additional reintroductions of the species to the NLP.