sexta-feira, 18 de janeiro de 2019

A caribou that was part of the Southern Selkirks herd, which once traversed the U.S.-Canada border. Biologists captured the last member of the herd this week.
David Moskowitz

The contiguous United States just lost its last wild caribou

The last caribou known to inhabit the contiguous United States has been removed from the wild. This week, a team of biologists working for the Canadian province of British Columbia captured the caribou—a female—in the Selkirk Mountains just north of the U.S.-Canada border. They then moved it to a captive rearing pen near Revelstoke as part of a controversial, last-ditch effort to preserve highly endangered herds. The female caribou is believed to be the last member of the last herd to regularly cross into the lower 48 states from Canada.

The 14 January capture of the caribou was “like losing a piece of the tribe in some way,” says Bart George, a wildlife biologist for the Kalispel tribe in Usk, Washington. It is one of two indigenous nations in the United States that have been pushing governments to maintain the cross-border caribou herd and protect its habitat.

In about a month, the British Columbia biologists plan to release the caribou—along with two other animals from another endangered herd—back into the wild, into a larger and more stable Canadian herd. The ultimate fate of these animals, however, is unclear. They are mountain caribou, a distinct ecotype of caribou found only in a forested swath of northwestern North America, which have become endangered because of habitat loss and other factors. Conservation efforts have failed to reverse population declines or prevent the complete extirpation of some herds at the southern end of the mountain caribou’s range, where they inhabit inland temperate rainforests. And biologists can’t say whether any caribou will again inhabit the continental United States. (There are herds of other types of caribou in Alaska.)

Battles over mountain caribou recovery have spanned decades. George, along with many conservationists, believes officials in British Columbia are looking for a way out of having to protect dwindling southern populations. Province officials dispute that idea. But critics note they have failed to develop management strategies for some southern herds, despite direction from the Canadian government calling for their restoration under the federal Species at Risk Act.

Conservationists also fear removing caribou from the wild will ultimately lead to the lifting of protections for its habitat, especially if the animals never return. Both British Columbia and the United States have identified and protected large areas of “core habitat” for mountain caribou. But adjacent lands, especially in British Columbia, have continued to be heavily logged, contributing to caribou declines.

It works like this: The disturbance benefits populations of other hoofed animals, such as moose and deer, which in turn attract predators such as wolves and mountain lions. The predators then spill over into the remaining patches of protected habitat, where they feed on caribou. Because of that dynamic, it is not clear whether “it will be possible to recover some of those herds,” says wildlife biologist Aaron Reid of British Columbia’s forests ministry in Penticton, which is responsible for caribou conservation. “The habitat may be too far gone.”

Provincial officials say they have no current plans to remove caribou habitat protections for the southern herds. But, “It’s hard to believe that,” says Candace Batycki, a program director at the Yellowstone to Yukon Conservation Initiative in Nelson, Canada. That’s because the province has lifted protections in the past after other caribou herds became extirpated and officials deemed it impossible to restore them.

What hangs in the balance, observers say, is not just the survival of a unique caribou population, but also the ecological integrity of the entire inland temperate rainforest. “The protections on core habitat for caribou are an umbrella, huge umbrella, that protect so many other species,” Reid says. “That’s the big story.”

Correction, 17 January 2019, 6:00 p.m.: The headline and story incorrectly characterized the caribou as the last in the continental United States. It was the last in the contiguous United States.
Posted in:
doi:10.1126/science.aaw7110

David Moskovitz

David Moskovitz is a photographer and journalist based in Winthrop, Washington. He is the author of Caribou Rainforest: From Heartbreak to Hope (Mountaineers Books/Braided River, 2018).

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