Statesman

Issue date: 10/28/09 Section: Outdoors

Media Credit: Ron Moen/SUBMITTED

Media Credit: Ron Moen/SUBMITTED Adult female moose cow with a young calf.

Studies of the moose, one of the most iconic and gentle creatures in Minnesota's repertoire of animal wildlife, indicate their populations are on the forefront of creatures most susceptible to global warming.

Over the past 20 years, moose populations of Northwestern Minnesota have declined from at least 4,000 moose to fewer than 100. A new study to be conducted in part by UMD will indicate if this same fate is beginning to effect the moose populations in Northeastern Minnesota as well.

UMD Ph.D. Biologist Ron Moen was a member of the Moose Advisory Committee (MAC), which diagnosed the problem and is instituting the new study this winter to better understand what has made moose mortality rates rise so abruptly.

"The decline was found to be correlated with warmer summer and winter temperatures," Moen said. "Moose are known to be vulnerable to high temperatures; our new study will help us to more specifically understand the relationship between moose behavior and temperature."

The MAC, formed by the Minnesota DNR, is a collection of moose biologists, land and wildlife managers and public representatives charged to make recommendations to the MN DNR on managing moose populations in Minnesota.

The new study incorporates GPS technology that enables moose to be tracked more efficiently than the radiocollars used in the past. "With the radiocollars it was necessary to fly over to determine if a moose was still alive," Moen said.

Using radiotelemetry flights to find dead moose is too slow to enable biologists to determine the cause of death in many cases, "60 percent of dead moose found by radio telemetry deemed the reason for moose mortality cause unknown," Moen said.

This coming winter, about 20 of the moose in Northeastern Minnesota will be collared with GPS devices that allow researchers to pinpoint moose locations within three to five yards every 15 minutes. "We hope to find out a moose is dead and be at the body within 48 hours of death to determine the cause of death," Moen said.

UMD Integrated Biological Sciences graduate student Amanda McGraw may also be able to utilize information from the GPS study with an eye to an important element of the population density problem, calving sites.

"What we are trying to do is determine what is unique about the northern Minnesota calving sites and better understand how the moose use their landscape," McGraw said.

McGraw said moose generally stick around where they have given birth for two weeks, and that there have not been conclusive studies about why or where moose choose to give birth in their home range. The calving location analysis she is conducting will allow McGraw to see what cover types -trees, what kind, deciduous or coniferous -are important to a moose when it comes time to give birth.

One theory for the declining population is that because of the moose's susceptibility to heat-stress, their eating patterns change when it is too warm to feed, at which point the moose will seek cover. This can cause feeding to switch to night-time, when it is harder to find leaves and twigs to eat.

The other suspected culprits for falling moose numbers are brainworm, liverfluke and winter tick parasites carried by white-tailed deer in the northern forest. According to Moen, when there are warmer temperatures, you have more deer. Although the deer are nearly unaffected by these parasites, the same cannot be said for the moose.

But an unlikely cause for moose decline is the overhunting of moose, which is limited to less than 2 percent of the population. The rationale for which is that only the bulls are to be hunted, and the amount of moose taken does not negatively affect reproduction.

The famous Wolf and Moose Study of Isle Royale is the longest running large predator study of its kind, and in its 50th year it is beginning to see some contentious results. In 2007, the moose population was the lowest it has been since the study began; "It's not simply just predator-prey," Moen said. "The goal of our research is to tell us why."

The boreal forest of Northeastern Minnesota is an ecosystem unique enough to hold many northern species, such as the gray wolf, the Canada lynx, and moose. Currently, the moose population in northeastern Minnesota may be declining. Ideally the research of Moen, McGraw and the MAC will provide us with a link, allowing the moose to be preserved in the wild rather than in history.

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