Just four of 19 caribou transplanted into the Purcell Mountains west of Cranbrook are still alive, less than one year after the transplant.
Since the animals were brought to the area from northern B.C. last March to boost a dwindling herd, most have been killed by cougars or wolves, according to Steve Gordon, project manager of the Purcells South Mountain Caribou Herd Augmentation.
“This is an unfortunate result. We are quite disappointed,” said Gordon. “Obviously this isn’t the success we had hoped for, but we are learning a lot from this that will inform how we proceed on other transplants and management of other herds in southern B.C.”
The endangered animals were brought from Dease Lake in northern B.C. in March in an attempt by the provincial government to revive a dwindling herd in the backcountry between the East and West Kootenay.
There are less than 1,700 mountain caribou in existence. The Purcells South herd had around 14 animals before the transplant.
To boost the local herd, 20 mountain caribou (17 females, three males) were taken from a healthy herd on the Tahltan First Nation, fitted with GPS radio collars then brought down to the Kootenays in specially designed animal trailers. One female caribou died en route.
Unfortunately, the transplanted animals could not be dropped in the same draw as the resident herd because of poor weather conditions. Perhaps as a result, the transplanted caribou began to explore the area, with some heading out of their alpine habitat above 1,400 metres or 4,500 feet to the valley bottom around Cranbrook and Creston.
“When they are wandering, they are at high risk. One of the things we are looking at to improve the chances of success of future transplants is: how can we reduce that wandering?” said Steve Gordon.
Some made it as far as the United States. Four of the 15 caribou that have died were in the U.S.: three in Montana and one in Washington.
“These are remarkable animals. They have made some extensive movements,” said Gordon.
The other caribou have remained in B.C., though some have swum across Kootenay Lake, while others wandered into the Rocky Mountains.
According to Gordon, five caribou have been killed by cougars and three by wolves.
“One important thing to note is that with only one exception, which is the most recent mortality, all of the predation mortalities have occurred when the caribou have wandered into low elevation areas,” he said.
Three of the transplanted caribou died in accidents: one fell through ice into a stream and couldn’t get out; one fell off a cliff; and one broke its leg and was subsequently preyed upon by a cougar.
Four died of unknown causes, and their bodies have been sent to the University of Calgary’s Faculty of Veterinary Medicine to determine cause of death.
March’s caribou transfer was to be the first in a two-part relocation project, a last ditch attempt to save the endangered herd in the Kootenays. The efforts are mandated under the federal Species At Risk Act. Gordon said the cost of capture, transport, release and incidental costs of the March relocation was $134,000. That amount doesn’t include the GPS collars, which can be reused, and research.
The transplant isn’t the only effort the team has undergone to save the endangered Purcells South herd, Gordon added.
“Transplants are always risky. It’s certainly not the desired way to manage caribou,” he said. “It’s only one of the management tools and a lot of the other management tools have been used in this area, including very significant habitat protection and management of human activities in that area. There has been a lot of cooperation from the forest industry and snowmobile clubs and associations that we want to acknowledge. This is a critical intervention. It’s not something we embark on without serious reflection.”
Gordon said it has not yet been determined whether another transplant will take place.
“It’s safe to say we certainly wouldn’t be proceeding exactly as we did on this one. We would be applying what we have learnt through this transplant.
“As unfortunate as these results are, we are learning a lot from it. It is hopefully going to benefit mountain caribou in the long run.”