Phylogeography of four species of boreal-adapted rodents in the central Rocky Mountain region (Tamiasciurus hudsonicus, Marmota flaviventrus, Clethrionomys gapperi, Microtus montanus, Colorado, Wyoming). [Phylogéographie de quatre espèces de rongeurs boréaux dans la région de Central Rocky Mountains].

Résumé

Scope and method of study. DNA sequence data and restriction fragment length polymorphism (RFLP) analysis of segments of the mitochondrial (mtDNA) genome were studied to examine the phylogeographic structure of the red squirrel (Tamiasciurus hudsonicus), yellow-bellied marmot (Marmota flaviventris), red-backed vole (Clethrionomys gapperi), and montane vole (Microtus montanus) in the central Rocky Mountain region. Findings and conclusions. Short-grass prairie, intermontane basins, and arid river valleys serve as ecological obstacles for gene flow for these 4 species throughout the central Rocky Mountain region. Phylogeographic structure appears to be the result of an interaction between each species, affinity for boreal habitat and habitat patchiness at the landscape level. Climatic oscillations and shifts in vegetational zones that occurred during and following the Pleistocene had a profound impact on the phylogeographic structure of these 4 species, particularly for mountain ranges in eastern Wyoming and on either side of the Green River Canyon and Wyoming Basin. Tamiasciurus hudsonicus probably resided in northern and southern refugial populations during the Pleistocene as a result of the presence of montane glaciers in central Colorado.