A precipitous drop in wolf viewing opportunities for Denali National Park visitors is being attributed to increased hunting of the predators on lands next to the park, though Park Service personnel haven't publicly voiced that connection.

“We are just beginning to learn about the factors, such as pack disruption, that play a role in magnifying the impacts of individual wolf losses on viewability,” Dr. Philip Hooge, the park's assistant superintendent for resources, science, and learning, said when the park released data on the visibility of wolves along the Denali Park Road.

But Public Employees For Environmental Responsibility pointed to the state of Alaska's 2010 decision to do away with a buffer zone that had banned hunting and trapping of wolves in a 122-square-mile area of land due west of Healy, Alaska, that follows the Stampede Trail as the cause behind the reduced wolf sightings.

According to the park's wolf viewing report, this past summer marked the third consecutive year that researchers "found that visitors traveling in buses on the Denali Park Road have had significantly declining opportunities to see wolves. In a random sample of 80 bus trips this summer, wolves were seen on three occasions, or about 4 percent of the trips. By contrast, in the three previous years the percentages were 12 percent (2012), 21 percent (2011) and 44 percent (2010)."

In 2010, the Park Service had asked the Alaska Board of Game to expand the buffer zone, which would have prohibited hunting and trapping in additional areas where many of the most-viewed wolves winter. But the board not only declined the request, but voted to entirely eliminate the buffer along the park’s northeast boundary.

With the buffer no longer intact, wolves that leave the park and follow caribou to wintering grounds on this landscape are subject to hunting and trapping in some places. But Game Board officials say the alleged connection between hunting and trapping and fewer wolf sightings is wrong. Rather, said Ted Spraker, the board's chairman, a reduction in prey is behind the drop in wolves in the area.

According to park data, Denali's wolf population north of the Alaska Range has declined from 116 wolves in 2006 to just 55 in spring 2013 – a drop by more than half in just six years, and the lowest level documented since the counts were started in 1986. Dr. Hooge said that while this low number has impacts on the visitor experience and may have ecosystem effects, the wolf population remains viable.

Park research also shows that the decline of wolf numbers has not translated to larger numbers of viewed prey species. "The proportion of bus trips where bears, moose, caribou and sheep were seen varies by year, but none show the steady decline found with wolves," a park release said.

At PEER, experts said the decision in 2010 by Alaska to do away with the buffer zone was short-sighted.

“This precipitous decline in wildlife viewing success appears to be unprecedented in the history of the national park system,” said Rick Steiner, a retired University of Alaska professor and PEER board member who has led efforts to persuade the State of Alaska to restore the buffer. “The State of Alaska should understand the simple economics of this. In places like Denali, wolves are worth far more alive than dead. Removing the buffer benefits two or three trappers, but costs thousands of park visitors the opportunity to watch wolves in the wild, and thus costs the Alaskan economy.”

The National Park Service and state of Alaska in recent years have had a tenuous relationship over wildlife management. A month after the Game Board voted 4-3 in 2010 to do away with the buffer zone, Park Service officials moved to institute hunting and trapping bans to protect wolves and bears in their preserves in the state.

Alaska's approach to wildlife management has been described by critics as designed to reduce predator populations so there will be more game animals, such as caribou and moose, for hunters.

Earlier in 2010, a four-member wolf pack from Yukon-Charley Rivers National Preserve was killed by state predator control agents. The state also adopted a regulation over Park Service objections that allows black bear hunters to use artificial lighting in hunting sows and cubs at den sites inside national preserves. (Note: While hunting generally is prohibited within national parks, national preserves often are open to hunting and, in some cases, even energy development.)

In its response, the Park Service temporarily closed Yukon-Charley Rivers to the taking of wolves. At the same time, a ban on taking of black bear sows and cubs in Gates of the Arctic National Preserve and in Denali National Park and Preserve cubs at a den site while using artificial light wwas implemented by the agency.

The Park Service explained that the temporary closures were necessary due to a significant drop in Yukon-Charley Rivers' wolf population and to support the agency's responsibility for managing "naturally functioning ecosystems."

(Following an investigation into the killing of the Yukon-Charley Rivers wolf pack, Park Service officials said an honest mistake led to the shootings. Specifically, they said the Fish and Game agents who shot the wolves had not been given the correct radio frequencies assigned to collars two of the four wolves were wearing.)

At PEER, Executive Director Jeff Ruch said Alaska's approach to wildlife management will translate into reduced tourism.

“Why would tourists shell out hundreds of dollars to travel long distances to a crown jewel nature park where the most iconic wildlife is missing?” he said in a prepared statement. “Alaska loses big time if its incomparable national parks cease to remain robust tourist magnets.”

Denali has an annual visitation of more than 400,000, and roughly half that number ride on shuttle buses to Toklat (Mile 53) or beyond each year.