Last April, conservationists were alarmed to discover that the South Selkirk caribou herd, the only surviving population that ranges into the contiguous United States, had been reduced to just three individuals. In the following months, one of the caribou was killed by a cougar, and another disappeared from researchers’ radar due to a tracking collar malfunction. So, in a final-hour effort to keep the herd alive, conservationists have moved the last known South Selkirk caribou into a captive breeding pen, as David Moskovitz reports for Science.
The herd once migrated from British Columbia to the mountains of Idaho and Washington, and the relocation means no wild caribou roam the lower 48 states. The sole surviving South Selkirk caribou—a female—and two male caribou recently captured from another herd are now living in a 20-acre enclosure near the city of Revelstoke, British Columbia. In around a month’s time, biologists plan to release the caribou into a more stable herd. But their future, and the fate of other mountain caribou, remain precarious.
Mountain caribou make up a unique ecotype, which feed on the slow-growing lichen of centuries-old trees. The animals have thus been hard-hit by logging development, and they are also threatened by habitat loss and predation by wolves and other carnivores. Jim Robbins of the New York Times reported in April that southern mountain caribou in Canada had dropped from 4,500 to 3,800 individuals in a single year. Small sub-populations like the South Selkirk herd are particularly vulnerable; a single avalanche or harsh winter could wipe them out completely.
According to the CBC’s Bob Keating, a team of Canadian and American experts has been working for decades to salvage the South Selkirk herd. They tried bolstering the population with individuals from other herds, banned logging and snowmobiling in much of the herd’s range, and even implemented a controversial wolf culling program to protect the caribou from predation. The Kalispel Tribe in Washington state raised money to build a “maternity pen” for vulnerable herd members. But these efforts did little to help the population recover.
“We’ve really jeopardised their habitat over the last 30 to 40 years through unsustainable rates of logging,” Mark Hebblewhite, a Canadian wildlife biologist at the University of Montana, told Ashifa Kassam of the Guardian. “It’s all about habitat. You can do everything you want; you can kill wolves, you can kill invasive predators, you can kill species like moose … but without habitat what you’re doing is just buying time.”
Some experts have raised concerns that, with the South Selkirk caribou gone, protective measures will be lifted from their habitat. “There are a lot of pressures to reopen that landscape to logging again,” Candace Batycki, a program director at the Yellowstone to Yukon Conservation Initiative, told Eli Francovich of the Spokesman-Review. Snowmobiling permits are indeed now being issued for the Selkirk mountains, Francovich reports, but there are currently no plans to remove the logging ban.
Even if the last South Selkirk caribou fares well upon her release into a new herd, scientists don’t know if wild caribou will even again inhabit the contiguous United States. Caribou could one day be transplanted back to southern British Columbia, the CBC reports—but only if conservation efforts succeeded in reversing the fate of flailing herds.