North American red foxes originated from two separate genetic lineages that were isolated from each other by glaciers some half a million years ago, according to a U.S. Forest Service Pacific Northwest Research Station study.
The researchfeatured in the April/May 2011 issue of Science Findings, a monthly publication of the stationcan assist efforts aimed at conserving potentially imperiled montane populations of the species.
"When most people think of the red fox, they envision the ones that thrive in low-elevation, human-dominated landscapes," said Keith Aubry, a research wildlife biologist at the station who led the study. "But there are other extremely elusive and rarely seen populations that live only in isolated alpine and subalpine areas in the mountains of the Western United States."
The latter groupthe montane red foxesmay be imperiled by climate change and other contemporary pressures and were the focus of Aubry's doctoral work in the early 1980s. Contrary to prevailing theory at the time, Aubry hypothesized that native North American red foxes were descended from two distinct lineages, not one, that were isolated from each other in both northern and southern ice-free areas during the most recent Ice Age. Such an evolutionary history would help explain the unique ecological adaptations of the montane foxes, and why native red foxes in southern British Columbia are so much bigger than the montane foxes that occupy nearly adjacent areas in Washington's Cascade Range.
"If all of North America's foxes originated from a single lineage that had expanded its distribution in a wave across the continent, you'd expect to see a more or less continuous gradient in size," Aubry said. "But there was an abrupt discontinuity in size in that area, suggesting that the montane red foxes had evolved in isolation from the northern populations," Aubry said.
Only recently were Aubry and his colleagues able to test this h
|Contact: Yasmeen Sands|
USDA Forest Service, Pacific Northwest Research Station