In Richmond, the golden orange prothonotary warbler has been coming back from its Caribbean and South American wintering grounds a day earlier each year for nearly two decades as local temperatures have risen.
During the same period, Alaska's porcupine caribou herd has declined as climate changes have made it more difficult for the reindeer to feed and migrate during the spring.
The breeding range of the Baltimore oriole is projected to move so far north that it may no longer breed in Maryland.
(U.s. Fish & Wildlife Service)
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And warmer spring temperatures could dry up critical breeding habitat for waterfowl in the prairie pothole region, a stretch of land between northern Iowa and central Alberta.
These subtle shifts, documented in the first comprehensive assessment of climate change's impact on North American wildlife, indicate that warming has already altered migration routes, blooming cycles and breeding habits of animals and plants across the continent. The Wildlife Society's three-year study, being released today, adds a significant new dimension to the accumulating evidence that altered weather patterns, rising sea levels and hotter temperatures are already transforming regional ecosystems and having other observable effects.
"We are now looking at the consequences of warming on the areas where we recreate," said National Wildlife Federation senior science adviser Doug B. Inkley, a wildlife ecologist who supervised the eight scientists who wrote the report. "We are changing the environment and climate in which our wildlife live like never before. It is a huge experiment, of which the outcome is uncertain."
The 26-page assessment, which includes several species case studies as well as broad recommendations on how to accommodate changes in plant and animal behavior, comes from a nonpartisan group of wildlife experts. It follows a scientific study last month that found evidence that Arctic warming is threatening species in the northernmost latitudes. In another report yesterday, World Wildlife Fund researchers concluded that current climate change assessments probably underestimate the impact on many critical species.
The 9,000-member Wildlife Society, based in Bethesda, includes federal biologists, academics and wildlife refuge managers. It has yet to adopt a climate change policy, but it will vote in March on whether to endorse mandatory curbs on heat-trapping carbon dioxide emissions. The Bush administration opposes this approach, but some advocates of greenhouse gas restrictions, such as Sen. Joseph I. Lieberman (D-Conn.), said the report "imparts even greater urgency to our efforts to prevent the worst of climate change."
"After over 30 years of efforts to protect our planet's biodiversity by conserving their essential habitat, we are facing the very real threat that the warming earth could shift those habitats right out from under the species," Lieberman added in a statement. "Coupled with the continued fragmentation of wildlife habitat, global warming could create a deadly combination for the plants and animals that are a precious and critical part of our world."
Some climate change critics, such as Patrick J. Michaels, a climatologist and a senior fellow in environmental studies at the conservative Cato Institute, questioned the study. Although Michael Anderson, a waterfowl ecologist who directs Ducks Unlimited, Canada's institute for wetland and waterfowl research, suggested in the report that future warming and shrinking wetlands in the Great Plains and southern Canada could damage waterfowl breeding, Michaels said the overall increase in precipitation in the prairie pothole region more than compensated for any drying effects caused by recent temperature rise there.
"The balance will remain," said Michaels, who gets most of his research funding from public sources but accepts some money from the oil and coal industry. "People don't think to check the data before they make assertions."
Much of the debate over climate change has focused on what could happen in the future: The Wildlife Society's report charted both how species have been moving to cooler areas and adjusting their life cycles in recent decades, and how they might adapt to a predicted acceleration of warming in the next 100 years.
In some cases species have gone separate ways, disrupting a natural balance that existed for decades. Several types of warblers have been moving north near the U.S-Canada border, for example, leaving the spruce budworms they used to consume freer to attack local balsam firs. The World Wildlife Fund study found that rapid spread of the mountain pine beetle in North America and the oak processionary caterpillar's northward move in the Netherlands have eroded some forests.
"The thing of concern is the decoupling of communities that we know of today," said Terry L. Root, an ecologist and senior fellow at Stanford University's Institute for International Studies and one of the Wildlife Society study's authors. "Species shift differentially. It could cause a lot of trouble."
Not all species suffer as a result of warming, according to the report's contributors. Brad Griffith, a research wildlife biologist for the U.S. Geological Survey, said rising Arctic temperatures had hurt the porcupine caribou since 1989, but the populations of three other Alaskan herds had expanded.
"I find it fascinating to find this variability in response to climate change," said Griffith, who has worked in Fairbanks, Alaska, since 1991. "I relish it, but if I was a subsistence [caribou] hunter, then I might be less amused."
Thomas M. Franklin, the Wildlife Society's acting executive director, said he hoped wildlife professionals and state and local officials will accommodate these northward and inland population shifts by setting aside more land for conservation.
"What we need to do is interconnect habitats so there aren't huge gaps and barriers to overcome," Franklin said, adding that species could be in jeopardy if they're "stuck in areas from which they can't escape."
