Salmon and butterflies. Lilacs and honeysuckle. Marmots and robins. All of them are showing up earlier in the American West.
The region is full of examples of how global warming has triggered changes to the seasonal timing of plants and animals, especially in the spring, scientists say.
Up the Columbia River, salmon swim upstream earlier — more than 11 days since 1939 — to beat encroaching warmer waters. But that means they go hungry longer when they arrive, said Lisa Crozier, a research ecologist at the federal government’s Northwest Fisheries Science Center.
At the University of California at Davis, butterfly researcher Art Shapiro is watching all sorts of butterflies arrive earlier and earlier. And it has him a bit nervous because they may go dormant earlier in the fall and then starve, he said.
A Colorado mountain research preserve has tracked both robin and marmot emergence in the spring. Yellow-bellied marmots, which are related to the famed weather-predicting groundhog, are coming out of hibernation a month earlier than in the early 1970s; the birds appear a couple of weeks earlier on average.
Researchers in Alaska, where spring temperatures rose 4 degrees from 1970 to 2000, are seeing buds of birch, willow and aspen trees bursting 10 days earlier than they did in the late 1990s.
Pollen is bursting. Critters are stirring. Buds are swelling.
Biologists are worrying.
“Alarm clock running too fast”
“The alarm clock that all the plants and animals are listening to is running too fast,” Stanford University biologist Terry Root said.
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.
Biological timing is called phenology. Biological spring, which this year began at 11:48 p.m. MDT Wednesday, 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 these changes.
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.
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.”
Heat building in tissues earlier
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 20th century.
Lilacs in Montana, Idaho, Utah and elsewhere are blooming a couple days earlier per decade. The rate is even faster for shrubs in Arizona and wine grapes in California. Pears in Oregon are coming two weeks earlier than in the 1940s.
Even the West’s yearly summer wildfire season is coming earlier because plants are getting dry earlier. 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 source. “It’s all a part of life,” Weltzin said. “Timing is everything.”
Have say in what you see
The National Phenology Network is enlisting volunteers to help track early spring blooms and eventually changes in animals caused by global warming. When Project BudBurst debuted last year, thousands of people participated in 26 states. “All people can contribute to it by tracking the timing of flowering events or leaf-out events for plants and animals in their backyard,” said Phenology Network director Jake Weltzin.
The website gives directions on what to look for in different parts of the country.
The Associated Press
