Points North: Seeking Answers To Moose Decline—Before It’s Too Late

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Gonzo journalism is when the journalist becomes a participant in the story. I'm not sure it applies to clipping samples of moose browse along the Gunflint Trail. Researcher Dr. Ron Moen gave me a pruning clipper and a handful of paper bags to collect twigs as we started into the woods. Behind me, I heard graduate student Amanda McGraw quietly whisper, “Yes!” Clearly, snipping twigs is not her favorite task.

It was April 12 and we were wearing snowshoes because the forest was still blanketed with three feet of snow. Last winter, a helicopter crew had captured several moose in the vicinity and fitted them with GPS tracking collars as part of Moen’s research project. Other area moose wear similar collars as part of research being conducted by the Grand Portage Ojibwe. Today, however, we weren't looking for the collared moose, because the snow conditions made it tough to travel in the woods. Measuring browse availability was something we could do without venturing far from a plowed road.

The previous evening, Minnesota DNR veterinarian Dr. Erika Butler and Moen, who works at the University of Minnesota, Duluth’s Natural Resources Research Institute, gave presentations of their ongoing moose research projects at a public meeting sponsored by the Minnesota Deer Hunters Association in Grand Marais. About 30 people attended the meeting, most of whom seemed concerned about the plight of moose in northeastern Minnesota, where the majestic animals have noticeably declined in abundance during the past decade.

The researchers are trying to learn more about moose and why their numbers are diminishing. Butler's research focuses on collecting biological samples from moose killed by hunters or animals that perished for other reasons and are recovered before they decompose. She is looking for diseases and parasites that may weaken or kill otherwise healthy moose.

What she’s finding is moose in the Arrowhead are exposed to a variety of diseases and parasites, including West Nile Virus, Eastern Equine Encephalitis, Lyme’s Disease, P. Tenuis (brain worm) and liver flukes. What role diseases and parasites may play in moose mortality is not well-understood, which is why Butler hopes to collect more necropsy samples. She acknowledges that increasing numbers of white-tailed deer—which serve as vectors for brain worm and some other illnesses—may play a role in the moose decline.

“A lot of people think brain worm is driving the decline and that very well could be,” she said.

While she often hears questions about the role wolf predation plays in moose survival, Butler says half of the radio-collared moose that have died and been recovered by biologists showed no signs of being scavenged by wolves. On those where wolves fed on the carcass, it was difficult to determine if they’d killed the animal.

However, researchers are not sure if predation plays a role in calf survival. What they know is that despite strong pregnancy and birth rates, a declining number of calves survive their first year. In fact, calf survival is now so low it may be difficult for the moose herd to recover. Moen hopes to learn more about what is happening to moose calves by monitoring the daily activities of their mother via GPS.

Moen's project is following collared moose in several locations across northeastern Minnesota and in Ontario's Quetico Provincial Park. The GPS collars allow biologists to closely follow the animals’ daily movements and learn how they respond to changes in air temperature. Cows with calves may suddenly change their daily habits if they lose the calf, hopefully allowing researchers to follow up on the ground and learn what happened to the calf. Additionally researchers want to learn more about the habitat preferred by moose through the seasons of the year—information that could be used to guide forest management decisions.

So far, the data collected since this winter shows when the snow is deep, moose spend most of their time in one general area, presumably where they find ample browse and sufficient cover. When he's walked into places being used by collared moose, Moen has noticed evidence of heavy browsing. He'd like to learn more about how much woody browse is available for hungry moose.

My instructions were simple. Snowshoe through the woods and look for stubby twigs where moose had been feeding at sometime last winter. Clip a few of the stubs and put them in a paper bag marked with the name of the tree species. Next, clip a few unbrowsed twigs of the same diameter and put them in another bag. Then go find some more.

I quickly discovered the best way to accomplish this task was to think like a moose wandering through the woods looking for something to eat. We started out in a mature aspen forest with surprisingly little browse. I found where a moose munched on aspen saplings and hazel brush. Next, we walked along a gentle slope where white spruce were planted many years ago. Shrubs of several species grew in a series of small openings among the conifers.

As a shed antler hunter, I knew this was a wintering area. I clipped a few browse samples from hazel, willow and aspen. A couple of times, I found twigs that looked like they'd been clipped with pruning shears—or the sharp teeth of a snowshoe hare. The blunt teeth of moose crush and tear the twigs.

While there was plenty of evidence of browsing in years past—many shrubs had a gnarled, bonsai appearance from past years of repeated browsing. Some of the balsams growing along the clearing edges had bare trunks extending nine or 10 feet up from the ground because foraging moose once ate all of the lower boughs. None of the balsams had been browsed last winter.

We turned back when the morning sun began to soften the snow, making it difficult to walk even with snowshoes. While we collected some samples of browsing from last winter, looking at the damage to trees and shrubs evident from past winters, I couldn’t shake the feeling that we just walked through the forest equivalent of a moose ghost town. Hopefully, we’ll learn what we need to know to stem the population decline before the only moose in Minnesota are ghosts.

Airdate: April 22, 2011

Photo courtesy of Jonathan Brennecke via Flickr.

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