Spring keeps coming earlier for birds, bees, trees|
By Seth Borenstein, AP Science Writer
WASHINGTON — The capital's famous cherry trees are primed to
burst out in a perfect pink peak about the end of this month. Thirty
years ago, the trees usually waited to bloom till around April 5.
In central California, the first of the field skipper sachem, a
drab little butterfly, was fluttering about on March 12. Just 25 years
ago, that creature predictably emerged there anywhere from mid-April
How was your winter?
Climate change, weather research
And sneezes are coming earlier in Philadelphia. On March 9, when
allergist Dr. Donald Dvorin set up his monitor, maple pollen was
already heavy in the air. Less than two decades ago, that pollen
couldn't be measured until late April.
Pollen is bursting. Critters are stirring. Buds are swelling.
Biologists are worrying.
"The alarm clock that all the plants and animals are listening to
is running too fast," Stanford University biologist Terry Root said.
Blame global warming.
The fingerprints of man-made climate change are evident in seasonal
timing changes for thousands of species on Earth, according to dozens
of studies and last year's authoritative report by the Nobel Prize-winning
international climate scientists. More than 30 scientists told The
Associated Press how global warming is affecting plants and animals at
springtime across the country, in nearly every state.
What's happening is so noticeable that scientists can track it from
space. Satellites measuring when land turns green found that spring
"green-up" is arriving eight hours earlier every year on average since
1982 north of the Mason-Dixon line. In much of Florida and southern
Texas and Louisiana, the satellites show spring coming a tad later,
and bizarrely, in a complicated way, global warming can explain that
too, the scientists said.
Biological timing is called phenology. Biological spring, which
this year begins at 1:48 a.m. ET Thursday, is based on the tilt of the
Earth as it circles the sun. The federal government and some university
scientists are so alarmed by the changes that last fall they created a
National Phenology Network at the U.S. Geological Survey to monitor
The idea, said biologist and network director Jake Weltzin, is "to
better understand the changes, and more important what do they mean?
How does it affect humankind?"
There are winners, losers and lots of unknowns when global warming
messes with natural timing. People may appreciate the smaller heating
bills from shorter winters, the longer growing season and maybe even
better tasting wines from some early grape harvests. But biologists
also foresee big problems.
The changes could push some species to extinction. That's because
certain plants and animals are dependent on each other for food and
shelter. If the plants bloom or bear fruit before animals return or
surface from hibernation, the critters could starve. Also, plants that
bud too early can still be whacked by a late freeze.
The young of tree swallows — which in upstate New York are
laying eggs nine days earlier than in the 1960s — often starve
in those last gasp cold snaps because insects stop flying in the cold,
ornithologists said. University of Maryland biology professor David
Inouye noticed an unusually early February robin in his neighborhood
this year and noted, "Sometimes the early bird is the one that's
killed by the winter storm."
The checkerspot butterfly disappeared from Stanford's Jasper Ridge
preserve because shifts in rainfall patterns changed the timing of
plants on which it develops. When the plant dries out too early, the
caterpillars die, said Notre Dame biology professor Jessica Hellmann.
"It's an early warning sign in that it's an additional onslaught
that a lot of our threatened species can't handle," Hellmann said.
It's not easy on some people either. A controlled federal field
study shows that warmer temperatures and increased carbon dioxide
cause earlier, longer and stronger allergy seasons.
"For wind-pollinated plants, it's probably the strongest signal we
have yet of climate change," said University of Massachusetts professor
of aerobiology Christine Rogers. "It's a huge health impact. Seventeen
percent of the American population is allergic to pollen."
While some plants and animals use the amount of sunlight to figure
out when it is spring, others base it on heat building in their
tissues, much like a roasting turkey with a pop-up thermometer. Around
the world, those internal thermometers are going to "pop" earlier than
they once did.
This past winter's weather could send a mixed message. Globally, it
was the coolest December through February since 2001 and a year of
heavy snowfall. Despite that, it was still warmer than average for the
Phenology data go back to the 14th century for harvest of wine
grapes in France. There is a change in the timing of fall, but the
change is biggest in spring. In the 1980s there was a sudden, big leap
forward in spring blooming, scientists noticed. And spring keeps
coming earlier at an accelerating rate.
Unlike sea ice in the Arctic, the way climate change is tinkering
with the natural timing of day-to-day life is concrete and local.
People can experience it with all five senses:
• You can see the trees and bushes blooming earlier. A photo
of Lowell Cemetery, in Lowell, Mass., taken May 30, 1868, shows bare
limbs. But the same scene photographed May 30, 2005, by Boston
University biology professor Richard Primack shows them in full spring
• You can smell the lilacs and honeysuckle. In the West they
are coming out two to four days earlier each decade over more than
half a century, according to a 2001 study.
• You can hear it in the birds. Scientists in Gothic, Colo.,
have watched the first robin of spring arrive earlier each year in
that mountain ghost town, marching forward from April 9 in 1981 to
March 14 last year. This year, heavy snows may keep the birds away
• You can feel it in your nose from increased allergies.
Spring airborne pollen is being released about 20 hours earlier every
year, according to a Swiss study that looked at common allergies since
• You can even taste it in the honey. Bees, which sample many
plants, are producing their peak amount of honey weeks earlier. The
nectar is coming from different plants now, which means noticeably
different honey — at least in Highland, Md., where Wayne Esaias
has been monitoring honey production since 1992. Instead of the rich,
red, earthy tulip poplar honey that used to be prevalent, bees are
producing lighter, fruitier black locust honey. Esaias, a NASA
oceanographer as well as beekeeper, says global warming is a factor.
In Washington, seven of the last 20 Cherry Blossom Festivals have
started after peak bloom. This year will be close, the National Park
Service predicts. Last year, Knoxville's dogwood blooms came and went
before the city's dogwood festival started. Boston's Arnold Arboretum
permanently rescheduled Lilac Sunday to a May date eight days earlier
than it once was.
Even western wildfires have a timing connection to global warming
and are coming earlier. An early spring generally means the plants
that fuel fires are drier, producing nastier fire seasons, said
University of Arizona geology professor Steve Yool. It's such a good
correlation that Weltzin, the phenology network director, is talking
about using real-time lilac data to predict upcoming fire seasons.
Lilacs, which are found in most parts of the country, offer some of
the broadest climate overview data going back to the 1950s.
This year, though, it's the early red maple that's creating buzz,
as well as sniffles. A New Jersey conservationist posted an urgent
message on a biology listserv on Feb. 1 about the early blooming. A
2001 study found that since 1970, that tree is blossoming on average
at least 19 days earlier in Washington, D.C.
Such changes have "implications for the animals that are dependent
on this plant," Weltzin said, as he stood beneath a blooming red maple
in late February. By the time the animals arrive, "the flowers may
already be done for the year." The animals may have to find a new food
"It's all a part of life," Weltzin said. "Timing is everything."
Original article: USA Today
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