Breeding ducks in the prairie pothole region of North America, which stretches from northern Iowa to central Alberta and includes northern Montana, could experience significant population declines from global warming, according to a new study.

The forecast for waterfowl in the prairie pothole region is one of the findings in a study released on Wednesday by the National Wildlife Federation and the Wildlife Society.

The report, titled ''Global Climate Change and Wildlife in North America," is the first comprehensive assessment of global warming's likely consequences for the continent's wildlife from wildlife professionals.

''We're concerned about the effects of global warming on wildlife in North America , and this assessment verifies that some species already are responding to climate change, said Tom Franklin, acting executive director of the Wildlife Society.

The report warns of possible major shifts in ranges and the restructuring of entire plant and animal communities and the disappearance of some forest types in the United States.

Douglas B. Inkley, NFW's senior science adviser and chair of a Wildlife Society committee that wrote the report, said, "Global warming presents a profound threat to wildlife as we know it in this country."

The study found that climate change already is affecting wildlife in North America and will continue to do so.

Glaciers in the prairie pothole region, which the study calls the "duck factory of North America," left millions of small ponds that are used by breeding waterfowl. Extensive drought has affected the wetlands and the reproductive rates of ducks, the report said.

"Most scenarios and models predicted significant declines in wetlands and thus declines in the abundance of breeding ducks in this region by the 2080s," according to the study.

Projected declines in duck breeding range from 9 percent to 69 percent.

The report also details the disruption of ecological processes, displacement or disappearance of coastal wetland species, significant loss of coastal marshes and disruption of Alpine and Arctic ecosystems.

In addition, the study reports direct threats to many species, including polar bears, migratory songbirds and waterfowl and alpine amphibians.

Based on the report, the Wildlife Society will consider adopting formal policy recommendations at its March meeting. Draft recommendations include such measures as a reduction of carbon-dioxide and other greenhouse-gas emissions and for state and federal wildlife agencies to consider climate change in developing long-range wildlife management plans.

The report is available on the Internet at www.nwf.org/news and at www.wildlife.org.