Post-glacial colonization of northwestern North America by the forest-associated American marten (Martes americana, Mammalia: Carnivora: Mustelidae)

Authors

  • Karen D. Stone,

    Corresponding author
    1. University of Alaska Museum, 907 Yukon Drive, Fairbanks, Alaska 99775, USA,
    2. Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska, Fairbanks, Alaska 99775, USA,
    Search for more papers by this author
  • Rodney W. Flynn,

    1. Alaska Department of Fish and Game, PO Box 240020, Douglas, Alaska 99824, USA
    Search for more papers by this author
  • Joseph A. Cook

    1. University of Alaska Museum, 907 Yukon Drive, Fairbanks, Alaska 99775, USA,
    2. Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska, Fairbanks, Alaska 99775, USA,
    Search for more papers by this author
    • Present address: Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209–8007, USA.


Karen Stone. Present address: Department of Biology, Southern Oregon University, 1250 Siskiyou Blvd., Ashland, OR 97520–5071 USA. Fax: (541) 552 6415; E-mail: stonek@sou.edu

Abstract

Phylogeographic patterns were used to assess intraspecific diversification of American martens (Martes americana). Within martens, two morphological groups (americana and caurina) have been recognized, though the level of distinction between them has been debated. We examined mitochondrial cytochrome b gene haplotypes from 680 martens to explore the colonization history of the Pacific Northwest and found two clades that correspond to the morphological groups. The widespread americana clade extends from interior Alaska south to Montana and eastward to Newfoundland and New England (i.e. northwestern, north-central and northeastern North America). The caurina clade occurs in western North America, minimally extending from Admiralty Island (southeastern Alaska) south to Oregon and Wyoming. Our data indicated two colonization events for the Pacific Northwest (one by members of each clade) and were consistent with the persistence of populations throughout past glacial periods in eastern and western refugia. Due to vegetational and geological history following the past deglaciation, we hypothesize that martens of the caurina clade spread along the North Pacific Coast, and into southeastern Alaska, earlier than martens of the americana clade. Mismatch distributions for the americana clade were indicative of populations that recently experienced demographic expansion, while mismatch distributions for the caurina clade suggested that populations were at equilibrium. These clades are reciprocally monophyletic and distinctive (interclade divergence ranged from 2.5 to 3.0% (uncorrected p), whereas, intraclade divergence was < 0.7%), and two regions of sympatry have been identified. Genetic signatures of past admixture in hybrid zones may have been extinguished during subsequent glacial periods when ranges contracted. This recurrent pattern of relatively restricted western, or Pacific coastal, lineages and more widespread eastern, or interior continental, lineages exists across broad taxonomic groups and suggests a shared biogeographical history.

Ancillary