St. Paul — Wolves may be playing a larger role in the decline of Minnesota’s northeast moose population than previously believed, according to a recently published research paper.
The decline of the northeast Minnesota moose population that began around 2003 coincides with an increase in the wolf population in a portion of the moose range, the paper said.
The same research paper also refuted a previously published paper by the Minnesota DNR that asserted that climate change was contributing to the decline of the northeast Minnesota moose herd.
That paper also discounted the role wolves are playing, because it noted that wolf numbers in the state had remained steady before and after the moose population began its decline.
But this latest paper, authored by wolf expert Dave Mech and statistician John Fieberg, of the University of Minnesota, noted that the DNR’s study used statewide wolf population estimates, which suggested that while wolf numbers remained steady on a statewide level, the wolf population was actually increasing in at least a portion of the northeast Minnesota moose range.
Mech’s own research and monitoring of the wolf population, which included about 20 percent of the northeast Minnesota moose range, showed a rising wolf population in that area.
Mech is a noted wolf expert, a senior scientist with the U.S. Geological Survey, and founder of Ely’s International Wolf Center. He also was involved in the long-term study of the relationship between wolves and moose on Isle Royale, the national park that sits offshore of Minnesota’s Arrowhead region in Lake Superior.
Mech said he thought something was off in a pair of DNR research papers authored by Mark Lenarz in 2009 and 2010, which said climate change was playing a role in moose decline.
“I had an inkling that something was wrong, but I’m not a statistician,” he said.
So he reached out to Fieberg, who is a statistician, and is more familiar with the technique that DNR used.
“Our paper showed that those statistics were invalid,” Mech said, noting that it was still possible that climate change is playing a role in the decline of moose.
“Right now, I don’t think there is enough evidence to say that,” he said.
Mech’s paper was published a few months ago in The Journal of Wildlife Management and was titled, “Re-Evaluating the Northeastern Minnesota Moose Decline and the Role of Wolves.”
Mech said Lenarz, now retired, reviewed the paper before it was published but did not rebut the paper, he said.
“This is not an adversarial type of thing,” Mech said, noting that all of the researchers know each other. “Science is self-correcting. When one of us makes a mistake, we expect somebody else to correct it.”
As for the role wolves may be having on moose in northeast Minnesota, Mech said, from 1983 to 2003, the wolf population did not appear to be reducing the moose population.
“But starting at roughly 2003/2004, as the wolf population increases, there is a corresponding decrease in the calf/cow ratio,” he said. “We don’t want to say that correlation is necessarily causation, but when the main food source is moose, it allows you to add that factor. That probably is evidence of the effect of wolves on moose.”
Mech was careful to point out that his wolf study and wolf population estimates, northeast of Ely, only include about 20 percent of the northeast Minneota moose range.
In that area, there was almost a doubling of wolf numbers from 2003 to 2012.
“Our studies are done annually, and done locally in an area that overlaps the moose area,” he said. “This is still at least more likely to represent the wolf population than the entire state.”