By Seth Koenig
Bangor Daily News column
In 2011, the journal Science published a groundbreaking study that tracked the recent habitat shifts of nearly 1,400 animals, plants and insects, and the results were striking.
Researchers found that the species were moving away from the equator and into higher elevations two to three times as fast as they were just eight years earlier. Essentially, as the Earth’s climate changes and becomes, on average, warmer, each species’ climate sweet spot drifts incrementally north (for those species north of the equator).
The nearly 1,400 species studied were found to be following cooler climates at a rate of nearly 15 feet per day — a pace that adds up quickly.
The National Oceanographic and Atmospheric Administration and National Aeronautic and Space Administration called 2014 the Earth’s hottest year on record, continuing a warming trend that has seen 13 of the 15 hottest years recorded since 2000.
“These changes are equivalent to animals and plants shifting away from the equator at around 20 centimeters per hour, for every hour of the day, for every day of the year,” project leader Chris Thomas, a biology professor at England’s University of York, told Discovery News.
“We were able to calculate how far species might have been expected to move so that the temperatures they experience today are the same as the ones they used to experience, before global warming kicked in,” Ralf Ohlemüller, a researcher at Durham University in the United Kingdom, told the Christian Science Monitor. “Remarkably, species have on average moved towards the poles as rapidly as expected.”
In Maine, the steady migration of species north has brought us creatures such as the Virginia opossum, North America’s lone marsupial and an animal that was an extreme rarity in Maine prior to the last two decades.
Oh, and deer ticks. Today’s hikers and outdoor children must religiously check their bodies for the ubiquitous disease-carrying pests, but we sometimes forget that their parents and grandparents had no such burden. The first deer ticks were seen in southern Maine in the 1980s.
But species for which Maine is actually the southern end of their habitat range are gradually getting their passports stamped at the Canadian border. And some species are disappearing from Maine for more dire reasons: Their environment is changing faster than they can get away from it, and they’re dying off.
While many species in Maine are being affected in one way or another by these changes, here are six that may surprise people by leaving the state:
6. and 5. The American marten and the Canada lynx
From the 2009 University of Maine report titled “Maine’s Climate Future“:
“Both the American marten and Canada lynx travel easily in the snow. Martens hunt beneath the snow, and the lynx’s long legs allow for movement through soft, deep snows. Both species occur in northwestern Maine, the part of the state with the greatest average annual snowfall. Wildlife biologists expect that once annual snowfall declines below some estimated threshold — 270 centimeters [106 inches] per year for lynx and 192 centimeters [76 inches] per year for marten — these two species will decline and eventually disappear from the state, and will be replaced with two closely related but less snow-adapted species, the bobcat and the fisher.”
While some northeastern locations were hammered by snowstorms, the Allagash area of northwestern Maine received about 60 inches of snowfall this past winter.
4. The Atlantic halibut
This popular food fish was described by the University of Maine report as one of the “northern species that are at the southern end of their range in Maine.”
“The Gulf of Maine’s waters are warming — faster than almost any ocean waters on earth, scientists say — and fish are voting with their fins for cooler places to live,” reported the New York Times in December. “That is upending an ecosystem and the fishing industry that depends on it.”
Regulators have responded by shutting down the Maine shrimp fishery for two straight years, while black sea bass and blue crabs are among the formerly southern-dwelling ocean creatures starting to take up residence off the state’s rocky coast.
But the halibut’s gradual northern drift isn’t the only factor in its disappearance from Maine waters. The Atlantic halibut is classified as an endangered species after years of overfishing, and is considered a high risk of extinction in the wild.
3. The balsam fir tree
This popular Christmas tree species could be among those displaced by trees moving into Maine in greater abundance from the south.
Wrote R.G. Wagner of the University of Maine’s School of Forest Resources:
“If the past is any indication, projected global warming over the coming century will likely alter the growth and species composition of Maine’s forest. Predicting the nature of these changes, however, is a challenging task. … The largest potential influence and the one most difficult to predict is how climate change will alter the composition of tree species. Because Maine’s forests are in a transition zone between the eastern temperate forest to the south and boreal forest to the north, any climate induced changes to our forest are likely to occur quicker and be more pronounced here than in other places. In a warming climate it seems reasonable to expect that tree species currently at the northern edge of their distribution (e.g., eastern white pine, red maple, and sugar maple) will likely be favored over those species that are now at the southern end of their distribution (e.g., balsam fir, trembling aspen, and white birch).”
2. The common loon
The haunting call of the lake- and pond-dwelling loon is one of Maine’s signature sounds, and it’s hard to imagine the state without it. But this distinct black-and-white bird is among those described as likely to migrate north as the climate gets warmer.
Although the common loon has no known direct reliance on the tree species, a U.S. Department of Agriculture report found a strong correlation between the appearance of loons and certain trees Maine is expected to see fewer and fewer of in the coming years.
Even though the species aren’t tied to each other in a direct way, they favor the same climate conditions and seem to respond very similarly to ecological pressures.
“Because paper birch and balsam fir are projected to migrate northward, our model projects a major contraction in the loon’s range,” the Department of Agriculture report reads, in part.
Complicating matters for Maine’s loons are rising levels of mercury found by scientists in the birds’ blood.
A comprehensive study by Dr. David Evers, executive director of the Gorham-based BioDiversity Research Institute, found mercury levels in adult Maine and New Hampshire loons ranging from 1.3 parts per million to 10.8 ppm. The levels were also climbing, creeping up by 8.4 percent per year over the 18 years of research included.
In a previous interview with the Bangor Daily News, biology instructor Camilla Fecteau of St. Joseph’s College in Standish said a mercury level of 3 ppm in the blood of loons is the threshold at which the birds begin to struggle in their reproductive cycles.
Fecteau and others have attributed the increasing mercury levels to the fact that Maine is meteorologically “downwind” from most of America’s pollutant-producing coal-fired power plants, a place U.S. Sen. Susan Collins, R-Maine, described as “at the end of our nation’s air pollution tailpipe.”
1. The black-capped chickadee
Say it ain’t so. While studies indicate we’re likely a long way from losing the Maine State Bird outright, many researchers believe Mainers can expect to see less and less of this iconic little bird in the coming decades as it moves northward.
From the report, “Maine’s Climate Future”:
“Depending on the magnitude of climate change, the black-capped chickadee could become less widespread and less common in southern Maine, or could disappear from most areas except for western and northern Maine.”
Agreed the Department of Agriculture study:
“Both [moderate and severe climate change models] project a decrease in abundance [of black-capped chickadees] and contraction in range northward in response to the projected shift in January temperatures and the projected decrease in the abundance of yellow birch.”
Honorable mention: The moose
Like the chickadees and loons, moose are among the wildlife almost synonymous with Maine.
The University of Maine report made repeated mention of the moose’s steady climb northward and the pressures applied to its population by disease-carrying ticks, but the moose’s habitat range still extends all the way south to Massachusetts.
Even if the moose is migrating northward at the rate of 15 feet a day calculated for many species in the Science study cited above, some back-of-the-napkin math suggests it would take about 350 years for the lumbering creatures to clear Maine entirely — although it would obviously take much less time for them to disappear from southernmost places like York and Cumberland counties.
And environmental pressures like disease could exacerbate their disappearance.
“In the worst case scenario, for species confined to Maine or a small portion of our region, extinction here could mean global extinction,” the University of Maine report reads, in part. “Fortunately for most species, a decline in Maine may still leave them reasonably widespread and common in Canada, although having moose and loons in Quebec and not in Maine would be small consolation for Mainers.”