Wolverine density surprise in southern B.C. woodland
Wolverines are thought of as shadowy solitary carnivores, few and far between as they wander B.C.’s cold and unyielding northern boreal forests.
A new study based in the temperate forests of southwestern B.C., however, has discovered them in unexpectedly high numbers — and has photographs to prove it.
Ecofish Research conducted the study across 225 square kilometres as part of environmental research for the Innergex run-ofriver project in the upper Lillooet River drainage basin, northwest of Pemberton.
Researchers used remote cameras as well DNA hair samples obtained from barbed wire located beneath beaver meat placed up trees at five locations.
Aerial and snow-track surveys were also conducted.
They obtained evidence of at least four females and two male wolverines, and suggested they may have photographed a seventh wolverine, but had no DNA evidence to be certain.
The animal had a gruesome gash around its neck, suggesting it had escaped a trapper’s wire snare.
“This is a surprisingly large number,” confirmed researcher Heidi Regehr. “The results are really interesting to us.”
Others photos showed wolverines scaling the trees for the free meat, and one depicted two wolverines in the same shot, although any relationship between the two is unknown.
Based on provincial modelling, high-quality habitat is thought to yield about six wolverines per 1,000 square kilometres, compared with two individuals in lowquality habitat.
The upper Lillooet study involved about one-quarter of that expanse and had been rated low to moderate habitat, yielding perhaps one wolverine, said Regehr’s colleague, Deborah Lacroix.
The high numbers discovered in the upper Lillooet could be related to availability of a variety of food sources, including beaver, porcupine, snowshoe hare and salmon.
The ruggedness of the area may also represent good denning habitat, as well as scavenging for larger animals killed in snow avalanches.
The wolverine is the largest terrestrial member of the weasel family and is a species of concern in B.C. A subspecies that once existed on Vancouver Island has not been seen since 1992.
Males can have home ranges of about 1,000 square kilometres compared with about 300 square kilometres for females, Lacroix said.
Wolverines are trapped for their valuable fur, which is resistant to the buildup of frost and has long been used as trim on parkas.
The animal is also in demand for taxidermy.
Lacroix and Regehr presented their findings to a biology conference in Richmond. Their study can also be found in the journal Northwestern Naturalist.