We hear a lot about bears being killed on roads and rails this spring. This message came across my computer screen in a flash of electromagnetic radiation and pixels…
UTM: E. 0560373 N. 5669757 Kootenay National Park, Hwy 93S
- 1.5 km south of Marble Canyon, southbound ditch.
Wolverine - Female with distinctive white patches on chest - Appeared in good health - Teeth may indicate it is a young adult - Weighed less than 10km, but the ravens had taken a lot out of the abdomen/thorax. - Cause of death was most likely from a vehicle on the road but that is an assumption
- Carcass was spotted and picked up by our law enforcement staff, complete with a UTM. It was found at approx. 1130am. By it’s appearance and amount of scavenging, it looks to have been dead less than 24hrs, probably the night before (?).
These were the details that we received on Monday May 21st. Wolverine mortality on highways is a pretty rare occurrence in the mountain parks. In the combined Banff, Kootenay and Yoho national parks, there have been only 3 recorded mortalities of wolverines on highways since record-keeping began over 30 years ago: 1981, one of unknown sex and age on the same Hwy 93 South (Kootenay Parkway) near Vermilion Pass; 1988, adult male on TCH (unmitigated section); 1989, adult male on TCH (unmitigated section).
Wolverines may interact with highways less than other large carnivores, may have a greater aversion to roads, which might result in fewer road-caused mortalities.
There is little information on how frequently wolverines cross highways. In John Kreb’s wolverine study near Revelstoke, a radio-marked male crossed the TCH regularly. Matt Austin found during two winters that wolverine tracks crossed the TCH near Kicking Horse Pass 50% (3 of 6) of the time they approached the highway. Extensive wolverine snow tracking in the early 2000′s found only a handful of wolverine crossings of the TCH between Lake Louise and the Lake O’Hara junction – believed to be the creme de la creme of wolverine habitat in the Canadian Rockies.
Highly localized species that live in isolated habitat patches (think pika, mountain goat, etc.) may rarely fall victim to traffic-related mortality. These species may rarely be present in valley bottom habitat, but might need to cross long expanses of unsuitable habitat such as the Bow Valley during important dispersal events that serve to connect populations within their larger “metapopulation”.
The same is true for wolverines. They are typically associated with high subalpine/alpine habitats far from areas of human activity, including highway corridors. But for their metapopulation to persist over the long term, they need to be able to migrate, successfully disperse, and carry their genes across these “matrices” of suboptimal (even deadly) habitat. For this “connectivity” to be fully functional, these dispersing individuals need to not only cross the highway, but they need to survive and reproduce in the new area they occupy.
We can imagine many scenarios that might have been playing out on or shortly before Victoria Day. The young female wolverine may have been dispersing from it’s maternal range, trying to locate a new territory for itself. It might have been traveling with a sibling, exploring areas away from the maternal range, and it was the unlucky one.
We’ll never know the what’s or why’s. But we do know that the loss of any individual in a population that is extremely low density and has one of the lowest reproductive rate of any terrestrial mammal, and especially the loss of a female, can have big demographic consequences and potentially genetic too.
That is the objective of our wolverine research – to determine the effects of transportation corridors on wolverine dispersal, gene flow and population connectivity. This female was killed within our study area. We had wolverine visits to our Tokumm Creek hair trap site 2 of the 3 sessions last winter. We had other sites down valley along Hwy 93 South visited by wolverines too. We have DNA samples (tissue and hair) from the Victoria Day victim, so will be able to determine who was this young female and possibly who she’s related to in our study area. Ultimately, with all the sampled genetic data from our 6000+Km2 study area, we will be able to better understand the effect these highways have on slicing habitats and populations into smaller, isolated, more threatened units, and what that means for wolverine conservation.