New research published: Apostle Islands play key role in regional spread of American marten populations

Consider yourself fortunate if you’ve seen an American marten on the Apostle Islands. These small, fur-bearing mammals are hard to spot but fun to watch. The slender-bodied, state-endangered weasels are also the subject of ongoing research by scientists at the University of Wisconsin. Their work was the subject of a session at the 50th Anniversary Research Stewardship Symposium. It’s also the basis for a new scientific paper.

The researchers used DNA from hair samples to estimate how many animals are in the park and where their relatives live. They published the results of that work in late July, 2021. In it, they said they examined the unique genetic sequences of 483 individual martens, 43 of which inhabited the Apostle Islands.

“Our findings suggest that the Apostle Islands were naturally recolonized by progeny of translocated individuals and now act as a source back to the reintroduction sites on the mainland. We suggest that the Apostle Islands, given its protection from disturbance, complex forest structure, and reduced carnivore competition, will act as a potential refuge for marten along their trailing range boundary and a central node for regional recovery.”

The research, led by Matt Smith and Dr. Jon Pauli, found that many of the animals on the islands are related. Interestingly, one island marten was traced to a first-order relative 50 miles away on the mainland. First-order means sibling, parent or child.


Indirect gene flow between subpopulation pairs of American marten (Martes americana) within a regional recovery network: Apostle Islands (WI-AI), Chequamegon National Forest, Wisconsin, United States (WI-CF), Nicolet National Forest, Wisconsin, United States (WI-NF), central Upper Michigan (MI-Central), eastern Upper Michigan (MI-Eastern), and western Upper Michigan (MI-Western).

Marten study map
Map and description above it are from the publication

American martens eat both plants and animals including voles; their diet varies by season. They live alone except during the mid-summer breeding season. Litters of 1 to 5 kits are born the following spring.

American martens were heavily trapped at the peak of the north American fur trade. Populations peaked in 1820 and fell off dramatically until the turn of the century. Their habitat includes northern parts of the midwest and northeastern United States as well as Canada and Alaska. It’s great to know that the Apostle Islands are a safe haven for these fascinating animals.

Read the published scientific paper here. (Adobe Acrobat Reader required)