When you think of global warming and its impacts on fish and wildlife, species like elk, mule deer, antelope and moose aren’t the ones that always come to mind.
 But natural-resource officials say America’s beloved big-game species are acutely at-risk in what wildlife professionals from numerous agencies and organizations say is a changing global environment.
Milder winters, drier summers, fewer snowfalls, fiercer storms—all, officials say, point to a warming climate that is badly in need of attention. The big question—is global warming a natural cycle bound to correct itself, or is it caused by human activities that require a public policy remedy?
Although our knowledge of global warming is growing but still incomplete, wildlife officials say it’s too risky—and too much is at stake—to bet on it correcting itself. Simply put, action needs to be taken to reduce greenhouse gases that they say are warming the earth.
For big game—and I’m a passionate big-game hunter—the threats of globing warming are “real, persistent…and about to get much worse.”
 “You’d think that a warmer climate would take some stress off the big game populations,” says Mark Van Deusen (an avid deer hunter from Prescott Valley, Arizona) in Season’s End: Global Warming’s Threat to Hunting and Fishing, a sizeable report released recently by the Bipartisan Policy Center in Washington D.C., in conjunction with several leading conservation organizations.  “But it appears to me just the opposite is going to happen.”
Deusen’s opinion is shared by many big-game biologists across the country. In other words, he’s not alone. According to the report,
projections show that “global warming will expand the range of disease-carrying insects, accelerate the impact of crippling parasites and reduce the big game forage base—a scary trifecta of problems.
“Cold temperatures are a barrier that limit the spread of potentially devastating outbreaks of disease in our northern big game herds,” says Jim deVos, retired chief of research for the Arizona Game and Fish Department. “If that barrier comes down, big game will die from those diseases at a steadily increasing rate.”
         Wildlife professionals are also worried about what global warming can do to the intricate food web needed by our big-game species. They say higher levels of carbon dioxide likely mean reduced nutritional value of forage. “The leafy portions of plants will become more fibrous and tough and will contain concentrations of substances that diminish the ability to digest food,” says Dr. Ted McKinney, a research biologist for the Arizona Game and Fish Department. “As a consequence, big game will weaken andeventually die from malnutrition.”
Elevated levels of carbon dioxide could also reduce vital big game habitat. Wildlife officials say carbon dioxide levels will allow trees to out-compete other kinds of vegetation and reduce critical forage such as shrubs and forbs.
The stress on big game populations could reveal itself in several ways, according to the report:
• Big game health will decline and mortality will rise as infestations of parasites, pests and disease-carrying insects, no longer held in check by cold, increase in severity and geographic range.
• Across the continent, deer, elk and other big game populations will shrink as high levels of greenhouse gases make the plants they eat less nourishing and tougher to digest.
• Desert shrub zones, pinyon-juniper woodlands and numerous other big game ecosystems will be increasingly at risk from wildfires, which will burn with greater intensity and frequency as invasive species replace less fire-prone native plants.
• Pronghorn, elk and mule deer will lose vital habitat in many regions of the American West as rising temperatures allow trees and shrubs to overwhelm sagebrush ecosystems.
 • Rising temperatures will allow forests to climb to higher elevations, severely limiting the alpine habitats that support bighorn and other mountain sheep.
• As temperatures rise, moose, which are accustomed and uniquely suited to cold weather, will continue to experience declining pregnancy rates and suffer poor individual health, due largely to increased winter tick infestations. Populations will shrink and drift northward, eventually disappearing from the upper Midwest. That appears to be happening in my home state of Minnesota right now.
• As fragmentation and loss of winter ranges continue, mule deer and elk will dwindle in number in the Rocky Mountain states, the Intermountain West and the Northern Boreal Forest. In some locations, over time both species will disappear entirely.
If you’re worried about global warming and looking for lawmakers to act, you’ll have to wait until 2009, because Congress effectively punted climate legislation until after the presidential election. Indeed, the new President—either Sen. John McCain of Arizona or Sen. Barack Obama of Illinois—will have to take the lead on this pressing issue. Both men say they will. Here’s hoping they do.
Stay tuned.
Babe Winkelman is a nationally-known outdoorsman who has taught people to
fish and hunt for more than 25 years. Watch the award-winning “Good Fishing”
and “Outdoor Secrets” television shows on Versus (formerly OLN), Fox Sports
Net, Comcast Southeast, WILD TV and many local networks. Visit
www.winkelman.com <http://www.winkelman.com>  for air times where you live.
  Editor’s note: This column is one in an occasional series about how natural resource professionals say fish and wildlife could be impacted by global climate change.