A caribou bull amidst the trees in Jasper National Park in March 2015. N. Verrier/ Parks Canada
Work to restore declining caribou populations in the mountain parks continues despite the loss of a critical research partner late last year.
In November 2014, the Calgary Zoo pulled out of hosting a captive breeding program that would help supply caribou, classified as threatened under the Species at Risk Act, to the dwindling herds in the mountain parks.
Considered abundant in south Jasper prior to the 1970s, caribou are struggling in the mountain parks. In Banff they are deemed to be non-existent.
The partnership between the zoo, Parks Canada and the B.C. government, originally announced in 2011, would have seen approximately 20 caribou moved from wild herds in B.C. to the Calgary Zoo’s ranch facility south of Calgary. By the third year, first yearlings from the conservation herd would be introduced into the wild with the goal of supplying caribou to four to six sub-populations within the mountain parks over a 10- to 20-year period.
Now that the zoo has pulled out of the project, Parks Canada is working with its partners to determine the best approach to implement the captive breeding program.
“We’re really trying to determine what is the best location, what are the best approaches to do captive breeding and how it’s going to work,” said Jean-François Bissaillon, caribou conservation project manager. “Planning is a really key component to the project to make sure we start on the right foot.”
Bissaillon said that while there are no concrete timelines at the moment, Parks Canada is hoping to get started as soon as possible.
“One thing that is really important to consider is that captive breeding is only one tool of the toolbox to recover caribou in the mountain parks,” said Bissaillon.
There are five major threats to caribou populations identified under SARA’s recovery strategy released in June: predator-prey dynamics, predator access, direct human disturbance, habitat destruction and small population effects. Captive breeding addresses the latter.
Part of the challenge to restoring caribou is that conservationists are working with overly small populations that they need to make more robust.
“At one point the herd becomes so small that it’s not self-sustaining and that’s why captive breeding is really important at that point. The idea is to supplement existing small herds with animals over time to help rebuild that critical number and get them past that threshold where the herd will become self-sustaining over time. Also, over time it might be possible to introduce herds that are extirpated,” said Bissaillon, referring to plans to restore the species to Banff National Park, which lost its last five caribou in a 2009 avalanche north of Lake Louise.
But the biggest threat to southern mountain caribou are predator-prey dynamics, with approximately 50% of caribou mortalities in the Rockies caused by wolves.
In Banff, research to understand the effects of wolf predation was planned to begin this spring. Parks staff were set to collar wolves with GPS trackers in March, but the project was delayed until next year due to poor snow tracking conditions. The plan is to monitor the wolves for the next three years in order to gain insight on their movements throughout caribou range, among other things.
“We want to release caribou where they’ll have the greatest conservation value because there are so few animals to release and so many places in need. We want to make sure that when we release them, the caribou are going to have survival rates and do really well and one of the main factors affecting caribou is wolf predation,” said Jesse Whittington, a Parks Canada wildlife biologist for Banff National Park.
Caribou aren’t typically a prey species for wolves, which prefer to hunt animals like deer, moose and elk. They also tend to isolate themselves from these other ungulates in order to avoid predation.
But historically high elk populations, caused by decades of predator control, led to increased wolf densities once the carnivores were allowed to return to the area.
“Incidentally, they killed caribou. That’s when our numbers really started to tank,” said Whittington, who explained that caribou thrive when there are less than three wolves per 1,000 square kilometres.
Now that elk populations have declined — and as a result so have wolf densities — conditions should be favourable towards caribou. Except for the fact that radio collar data collected in 2010-12 showed wolves spending more and more time in caribou range.
“But conditions are always changing so we want to see if the amount of time wolves are spending in caribou range is changing over time,” said Whittington.
The wolf-monitoring project is expected to resume next spring depending on snow tracking conditions. It will inform Parks Canada on how the animals interact with other prey animals like mountain goats, and how they are using the seasonal nighttime Bow Valley Parkway closures, as well as different wildlife corridors.