MARQUETTE (AP) - The Upper Peninsula moose population is growing more slowly than before, possibly because of conditions related to a warming climate, scientists say.
The Michigan Department of natural Resources said moose numbers grew at a rate of 10 percent annually between 1997 and 2007. The increase has dropped since then to 2 percent, for an estimated total of 451 moose this year.
"As temperatures have increased, we're seeing some association with these declining populations," said Dean Beyer, a DNR wildlife research biologist based in Marquette.
This 2011 file photo shows a young bull moose at Presque Isle Park in Marquette. The Michigan Department of Natural Resources reports the growth rate of the Upper Peninsula moose herd has slowed in recent years, possibly due to climate change. (Journal file photo by Dave Schneider)
Moose are struggling more in some places than others. Minnesota canceled its hunting season for the iconic symbol of the northwoods because the population had fallen 35 percent over the past year and 52 percent from 2010.
New England has a much larger moose population and the range there may be expanding, although numbers may be declining in some northeastern states.
In North Dakota, the population appears to be holding its own or growing. But some Rocky Mountain states are experiencing declines. While Canada's moose population remains large, it's been falling across the border in Ontario.
Researchers are considering factors including disease and nutrition as possible explanations for declines.
One theory in Michigan is that rising temperatures have increased the number of whitetail deer, which carry the parasitic brainworm that is lethal to moose. Another possible culprit is loss of trees that often provide cover for the animals from natural predators.
Biologists have ruled out attacks from the U.P.'s gray wolves as a significant contributor, Beyer said. The area of the northwestern U.P. where moose are concentrated has not drawn wolf packs thus far.
Officials translocated moose to the area from Ontario in the mid-1980s in hopes of boosting their presence. Their numbers have remained too low to allow a hunting season.