Prince of Wales Island wolf population plummets
JUNEAU — Prince of Wales Island’s population of wolves declined 60 percent in just one year, according to a recent U.S. Forest Service briefing paper, leaving only 60 wolves on the island and 89 in the larger game management area — and that’s before last season’s known harvest of 29 wolves.
The decline, says the Forest Service briefing paper, “potentially increases the probability of ESA (Endangered Species Act) listing and will almost certainly become a factor in ongoing litigation against timber sales critical to the Tongass Young-growth Transition Strategy (e.g., Big Thorne).”
The percentage of female wolves in the area has also declined significantly, from 50 percent in 2013 to 25 percent in 2014’s sample population.
Regional Supervisor for the Alaska Department of Fish and Game Division of Wildlife Conservation Ryan Scott said ADF&G, which is partnering with the USFS on the study, is discussing the estimate’s implications and its impact on the harvest season, but has not yet made any decisions.
Scott pointed out that the population estimate was arrived at by using hair traps to DNA sample a northern area of POW. Those estimates were then extrapolated to the rest of the island.
“When we do that, there’s the assumption that everything — the density — is the same, and that’s probably not true. Things are different,” he said.
USFS biologist and Tongass Wildlife Program Manager Brian Logan said the project itself, which used both the 2013 and 2014 estimates, was aimed at establishing a way to estimate wolf population numbers. In that, he said, it was a success.
“In a dense rainforest, it can be difficult to count wolves,” he said. “Looking at this hair-snaring technique — we feel really good about the results of that.”
Just the same, he said he would call the fall in population estimates an “apparent decline.”
Though 89 wolves is the estimate, the range of wolves estimated is between 50 and 159. The population in 1994 was estimated at 356, and in 2003 at 345, using other population measurement techniques.
In 2013, the wolves were estimated to have a population of 221, with a range between 130 and 378.
“Now we have a high end (159 in 2014) that’s barely larger than the low end (130 in 2013),” Larry Edwards, of Greenpeace’s Sitka Field Office, said. “Fifty — in terms of genetics, that’s a bottleneck.”
Greenpeace, the Center for Biological Diversity, and their partners have petitioned for an endangered species listing for the wolves on POW and its nearby islands, saying the population is genetically distinct from other Alexander Archipelago wolves, “which are themselves a subspecies of gray wolves.” Both matters are debated — geneticist Matt Cronin has said Southeast Alaska’s wolves are not genetically distinct; other geneticists look at the same data and say they are.
Last year, the Board of Game reduced the quota in GMU2 from 30 percent of the estimated population to 20 percent.
“There’s already been a fairly significant reduction there,” Scott said.
“Nothing is off the table” as far as the harvest season, Scott said, but added that he does think there is enough of a population to allow some form of harvest.
At the moment, Greenpeace and its partners are unsure what action they’ll be taking, but will likely be requesting that ADF&G Commissioner Sam Cotten stop the season via an emergency order, Edwards said. They’ll also be acting on a federal level.
The federal subsistence harvest season starts Sept. 1; the state season starts Dec. 1. “The vast majority” of those hunting and trapping wolves in that management area are federally qualified to do so, the briefing paper states. Both seasons end March 31.
Cause of decline
Scott said researchers are unsure what’s caused the decline.
“The bottom line is we don’t know what it is right now,” he said.
He mentioned disease and a reduction of prey as potential causes, but added there’s no sign the wolves are suffering from disease, and deer numbers are high. Natural factors leading to death “are not indicated in the observed wolf population decline,” the briefing paper states.
Illegal take on POW has at times been estimated to be very high.
“Illegal take may at times equal the legal harvest (on POW),” wrote retired ADF&G biologist Dave Person and fellow scientist Todd J. Brinkman in a 2013 publication. Person was then the lead biologist studying POW’s wolves.
“I don’t know that it is or that it isn’t,” Scott said when asked if illegal trapping and hunting was a potential cause for the decline. “In previous studies, it’s been indicated as a significant concern. I like to think that it’s not, but I can’t say for sure one way or another.”
Edwards said the cause, to him, is clear — “human caused mortality.”
“It’s directly related to the density of logging roads on the island,” he said. “The mortality is both from the regulated season that Fish and Game conducts, as well as illegal take.”
The question of why the wolves’ population has declined, Logan said, is what researchers will tackle next.
“We do know that a number of factors affect wildlife populations. Wolves, like any other animal, are affected by trapping, natural mortality, nutritional requirements and weather,” he said. “Can I point my finger at any specific cause? No, I can’t. Over the years, there can be varying levels of trapping pressure, especially in areas we have roaded access, but that’s not what this project is intended to answer. Those kinds of questions are what I would consider to be the next step.”
“Even with 89 wolves, I think we can provide some harvest opportunity there,” Scott said, adding that he thinks of POW’s wolves as not genetically distinct from others in Southeast Alaska. “There’s multiple user groups — not just sport users. There are subsistence users for wolves, as well. Is (the estimate) going to be part of the conversation? Absolutely.”