Minnesota's game animals struggle as climate changes

We Minnesotans have always gotten a thrill at seeing a hulking moose moving through our swamps or forests, or an agile whitetail deer leaping through the woods. Not to mention a black bear crossing the road in front of our cars or one visiting our campsites.

But the survival of many of America's big game species is not assured, warns a National Wildlife Federation report, "Nowhere to Run: Big Game Wildlife in a Warming World." Some of America's most treasured big game animals are at risk because of climate change.

Heat-trapping gases are warming the planet and transforming the habitats on which big game depend, including here in the land of 10,000 lakes.

Climate change may be upsetting nature's timing. For example, it is linked to earlier spring vegetation. The timing of food supplies may not coincide with the usual timing of animals' reproductive cycles and thereby threatens the survival of their young. Mismatches like this can be tragic.

More-frequent droughts may be forcing black bears to move out of traditional habitats in search of food and into areas of human habitation. Some bears are becoming more active than usual during times when they normally hibernate because of warmer fall and winter temperatures.

Moose, which are especially sensitive to temperature changes, can become heat-stressed in summer when temperatures rise above 60 to 70 degrees. Summer heat stress leads to lower weights, declining pregnancy rates, and increased vulnerability to predators and disease. In fact, moose are facing a triple threat — rising temperatures, changing forest species and increased mortality from parasites.

Whitetail deer are susceptible to hemorrhagic disease (HD) caused by viruses transmitted by insects called biting midges. Midges are killed by freezing temperatures. HD is most common in the late summer and early fall; the disease typically subsides after the first autumn frost. Longer summers can expose deer to more disease-carrying midges. Currently, HD has not been found in Minnesota, but it has been found in cows in Iowa.

Climate solutions are not a secret. We need to reduce carbon pollution, transition to less-polluting forms of energy, and preserve and restore the ability of farms, forests and other natural lands to absorb and store carbon. We also have to manage our natural resources in new ways. The state Department of Natural Resources has accepted a warming planet and state as fact and is already working to deal with the changes.

We know what to do. We need the political will to do it. Minnesota's congressional delegation needs to support President Obama and the Environmental Protection Agency in efforts to tackle climate change. We urge Minnesotans to talk to their representatives about the changing outdoors.