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Mammals threatened by climate change

February 10, 2016

Many Pennsylvanians remain blissfully unaware that every decade for the past 40 years has been warmer than the previous decade. And 2015 was the hottest year since recorded weather history began.

So it’s no coincidence that almost every day we witness vivid news reports about destructive and costly hurricanes, tornadoes, floods, forest fires and droughts here in the United States and around the globe.

While humans may have the ability to adapt to the adverse effects of a warming climate, many wildlife species don’t have that luxury. Climate change is quickly altering critical habitats for native wildlife species that have survived for millennia.

The latest report from the National Wildlife Federation, titled “Big Climate Challenges Facing Small Mammals” documents how a warming world is harming even the smallest of critters all across America.

For example, the snowshoe hare is uniquely adapted to survive by altering the color of its fur coat from brown to white as summer sun gives way to winter snows. Unfortunately for the hare, this biannual wardrobe change is linked to the amount of daylight, not by the amount of snowfall. So as the number of days with snow cover decreases, their vulnerability to predation increases.

The snowshoe hare is listed as a “Species of Concern” in PA. Due to its declining numbers, the state game commission reduced the daily bag limit for hares in recent years. If these population trends continue, wildlife biologists fear the snowshoe hare’s range will retreat north out of Pennsylvania.

But the snowshoe hare is not the only species in trouble. Our state bird—the ruffed grouse, our state fish—the brook trout, and our state tree—the eastern hemlock are predicted to largely disappear from PA by the turn of the century.

Brook trout are so closely dependent on the cooling shade provided by streamside hemlock trees that at one time they were called hemlock trout. Sadly, an invasive insect known as the wooly adelgid is slowly but surely killing our majestic hemlocks.

In the past, cold winters kept the adelgid confined to the southern U.S. Today, this destructive pest has spread all the way to New England. As the hemlocks disappear, so do our priceless cold water streams.