Moose population boom, linked to climate change, inspires some hunting changes

A large bull moose stands in a stream
A bull moose stands in Nunavaugaluk Lake, October of 1997. The moose population in the nearby Togiak National Wildlife Refuge has boomed over the past three decades. (Photo by Andy Aderman/U.S. Fish and Wildlife Service)

In southwestern Alaska, where there is a mix of tundra, mountains, forests and river-crossed terrain, there has been a rapid transformation in the wildlife.

In the Togiak National Wildlife Refuge specifically, the moose population has increased a whopping 400-fold since the early 1990s, from just a handful a few decades ago to about 2,000 animals now.

The reason appears clear: climate change. Milder winters and the proliferation of vegetation correlate directly with the moose population boom, according to ongoing research by Sebastian Zavoico, a graduate student at the University of Alaska Fairbanks.

The strongest part of the trend seems to be in river-crossed areas on the western side of the refuge, where woody shrubs have spread into areas that used to be more tundra-dominated, said Zavoico, who has used mathematical analysis to compare climate and vegetation changes with moose population changes.

The Togiak moose changes are part of a global pattern, Zavoico said. “We know that species are shifting their distribution all over the world,” he said. “It definitely fits the mold, that’s for sure.”

‘Tundra Be Dammed’

In Alaska, the shifting populations include moose and snowshoe hares moving farther north onto territory that used to be strictly tundra but now has woody plants, such as the North Slope. It also includes beavers, which have become fixtures in some Arctic areas where they were rare only a few decades ago. Beavers not only take advantage of the new shrubby conditions but, through engineering their dams and lodges, are hastening permafrost thaw and other ecological changes, as described in a UAF-led study appropriately titled: “Tundra Be Dammed: Beaver Colonization of the Arctic.”

While the changes have been good for some species, including moose in the Togiak refuge, they mean trouble for others. Among the highest-profile losers in the transformation are caribou, which depend on tundra vegetation like lichen and moss.

Scientists working in western Greenland, for example, found a “trophic mismatch” that is bad for caribou calf survival. The plants are emerging earlier, thanks to warming temperatures, but the daylight-regulated calving season has not changed accordingly, meaning the animals are missing out on the most nutritious greenery when they need it most, the scientists found.

As in some other regions, the caribou and moose trends have gone in opposite directions around the Togiak National Wildlife Refuge. The region’s Mulchatna Caribou Herd, which numbered about 200,000 animals in the late 1990s, is now down to about 12,850, said Andy Aderman, a U.S. Fish and Wildlife Service biologist working at the Togiak National Wildlife Refuge. The low population count triggered an emergency hunting closure last year.

Hunting changes

For people who have traditionally relied on caribou meat, a shift to moose hunting is logical, Aderman said. “The need doesn’t go away,” he said.

In sharp contrast to the situation with caribou, moose-hunting seasons in the area are liberal, appropriate to the science about moose populations. There is even a concern about the moose population getting too big too quickly, devouring the plants and overwhelming the region’s carrying capacity. “Something we’d like to not see is starving moose,” Aderman said.

Around Alaska and the wider Arctic, the rapidly changing climate has sometimes created mismatches with hunting and fishing seasons. Sometimes the regulatory calendar, which can be difficult to adjust, misses the altered arrival of the fish and game the hunting and fishing rules target. Sometimes the designated seasons no longer match conditions for safe travel over the tundra, snow or ice.  Sometimes, hunting practices adjust.

In Kotzebue, for example, subsistence hunters are coping with a compressed season for their spring hunts of bearded seals. The ice floes that the seals rest on melt away earlier, so hunters make more frequent boat trips over a shorter time period, a change detailed in recently published research.

Six moose, seen from above, browsing in low willows
Six moose feed on willows in March of 2007 along Land Otter Creek in the Togiak National Wildlife Refuge, March 2007.
The refuge’s moose population has boomed over the past three decades. (Photo by Andy Aderman/U.S. Fish and Wildlife Service)

While seal-hunting success rates have been maintained, local people are having less success with the beavers that have proliferated in the Kotzebue region, said Alex Whiting, environmental specialist for the Native Village of Kotzebue.

Overall, beaver trapping is a lot of work for little reward, as “the fleshing and putting up of beaver is the most labor intensive of all the fur, especially for novices,” Whiting said by email, referring to the region’s fur-bearing animals.

Fur prices are low in the commercial markets, and fur from animals like sea otters is generally preferred, Whiting said by email. Harvesting beavers “is more complicated trapping than most, because most of the sign is underwater and the trap sites are covered in ice and snow,” he said, and working on the ice can be unsafe.

Around the Togiak refuge, the switch from caribou to moose hunting hasn’t always been easy, either. “I think some people prefer caribou over moose for flavor,” Aderman said. A single moose generally weighs about 120 pounds more than a single caribou, meaning some logistical challenges for hunters, he added. “One person can usually handle a caribou by themself,” he said.

Both people and bears adjust

While people are adjusting, so apparently are bears. They are famously reliant on the region’s rich salmon runs, but they are also learning to prey on the young moose calves available each spring.

Aderman said he has even seen bears lying in wait nearby when pregnant cow moose are bedded down and preparing to give birth.

In recent years, Zavoico said, the region’s staggeringly high rate of calf survival has dipped, potentially a sign of bear predation. “It seems like the story that I’ve heard is the bears are starting to take advantage of this new resource that they’ve never had before,” he said.

Alaska Beacon

Alaska Beacon is part of States Newsroom, a network of news bureaus supported by grants and a coalition of donors as a 501c(3) public charity. Alaska Beacon maintains editorial independence. Contact Editor Andrew Kitchenman for questions: info@alaskabeacon.com. Follow Alaska Beacon on Facebook and Twitter.

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