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Points North

Points North: Is the Moose Mystery a Matter of Habitat?

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Doctor Alan Ek wonders if Minnesota researchers are looking so hard at moose to find a reason for the animal’s precipitous decline that they are not paying adequate attention to the habitat changes occurring within state’s northeast moose range. Ek, head of the Department of Forest Resources at the University of Minnesota, and research fellow David C. Wilson published a paper in Minnesota Forestry Research Notes where they found recently disturbed and young forest habitat has declined within the moose range. Disturbances, primarily logging and fire, create prime moose habitat with an abundance saplings for browsing moose.

Ek and Wilson used data from the national Forest Inventory Analysis (FIA), which can be described as a census of America’s forests. The FIA gathers data from 1,258 permanent plots within the northeast Minnesota moose range on a five-year cycle, allowing forest managers to observe long-term trends and ongoing change occurring in the woods. Their data analysis found a steady decline in young forest acreage during the last 10 years. This isn’t surprising, because logging activity has decreased due to less demand from a recession-battered timber industry as well as a reduction in timber harvest on the Superior National Forest. Ek says the decline in young forest cover correlates with the decline in moose.

Dr. Alan Ek
Dr. Alan Ek

“I’m not surprised there are fewer moose,” he says. “The health of the moose herd wasn’t an issue when large areas of the forest were disturbed.”

He has a point. During the 1980s and 90s, Minnesota experienced a logging boom to meet the demand for building materials, paper and other forest products. At the time, it was common to see large, recent clear-cuts just about everywhere in the northern forest. It was also common to see moose—often in or near the openings created by the harvests. Arguably, this era was the height of moose abundance in northeast Minnesota.

Ek thinks it would be a good idea for researchers to look at 50 years of moose and habitat relationships, rather than the last five or 10 years. He suspects this may provide other insights about moose than the ongoing radio collar studies.

“I’m not sure tracking moose to death or near death will any background habitat patterns,” he said.

Ek has forwarded the FIA research notes to the DNR’s moose researchers, but is frustrated because he hasn’t yet received a reply. Northeastern Minnesota’s forest have continued to change throughout his lifetime, he says, from former small farms that gradually reverted to forest to periods of more logging activity. The Superior National Forest is moving toward timber harvest methods that will create less disturbance, which he thinks may mean fewer moose in the future.

Researchers say they are looking at various aspects of moose habitat amid a plethora of research projects. Ron Moen at the Natural Resources Research Institute in Duluth says researchers know there is less young forest habitat in the moose zone and are already looking into habitat issues with ongoing research projects. Some of the present habitat appears to be seeing increased use from moose. He’s heard moose hunters are reporting they see lots of moose in the vicinity of burned areas recovering from large wildfires that occurred in the past decade, such as the Cavity Lake, Ham Lake and Pagami Creek burns.

Moen’s work includes studying the use of available browse, as well as where the moose equipped with GPS-enhanced radio collars spend their time. Some research is also occurring under the auspices of a multi-organization habitat project funded by the Outdoor Heritage Fund, as well as another project to look at recent habitat changes in the Boundary Waters. A new research project by a PhD candidate will look at moose habitat restoration.

Mike Schrage, wildlife biologist for the Fond Du Lac Band of Lake Superior Chippewa, says wildlife managers have begun looking at how large wildfires are benefitting moose during the annual winter aerial population survey, as well as disturbances like prescribed (intentional) burns and logging sites. He said the large Little Indian Sioux Fire that occurred on the western side of the Boundary Waters in 1971 led to a significant increase in moose as the forest started to recover, but a study at the time found the same thing did not happen after a similar wildfire in Alaska. The conclusion was moose can respond to habitat improvement, but other conditions may prevent them from doing so. Today, those conditions may include the parasites, disease and predation that appear to be taking a toll on Minnesota moose.

“I’ve seen no evidence that habitat is driving our moose population on a landscape level,” Schrage says. “Doctor Ek’s paper hasn’t convinced me otherwise.”

Recent population surveys at Voyageur’s National Park, where no recent fires or logging has occurred, suggest the small moose population there has remained stable, Schrage says. And the 2013 North American Moose Conference was held in New England, where a state like Massachusetts has relatively abundant moose populations living in mature forests. He wonders if the link between moose and young forest habitat is “overdone,” because there may be other factors influencing moose abundance that we don’t understand.

Like Moen, Schrage can point to a handful of habitat-related ongoing research projects. He said moose numbers are generally high near the Cavity Lake and Ham Lake fires compared to many other areas. While moose are abundant in the burned area, researchers don’t have data about how many moose existed in the area before the fires and thus are reluctant to draw conclusions. The 2011 Pagami Creek Fire burned so hot that vegetation has yet to recover, so it has not yet led to an increase in moose.

It may take years for researchers to understand how moose relate to habitat, Schrage said. In a year or two, data from one of Ron Moen’s research projects will show how moose use habitat in a Lake County study area, but it may take five or 10 years to know how moose responded to the recent wildfires. Fond du Lac, the 1854 Treaty Authority, the Superior National Forest and the DNR have implemented a 20 year study as part of the annual moose survey to see how moose respond over time to recent fires and timber harvest.

Of course, every year that passes takes us one year further from the era of moose abundance in the 80s and 90s. In fact, scientists aren’t even using that abundance as a benchmark for the state’s moose population. Instead, they are using population data beginning in 2005, when the ongoing population collapse was well underway. This was the most recent time biologists tweaked the methods they use in the annual aerial population survey. Survey data from the 80s and 90s, when moose were numerous, is not considered to be directly comparable with current data.

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