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Spring comes earlier in U.S. for birds, bees and trees

WASHINGTON: Washington’s famous Japanese 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 to mid-May.

And sneezes are coming earlier. On March 9, when allergist Dr. Donald Dvorin set up his monitor in Philadelphia, Pennsylvania, maple pollen already was 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. Thursday is the first day of spring in the United States, the warm, easygoing few months before the summer hot season.

“The alarm clock that all the plants and animals are listening to is running too fast,” said Stanford University biologist Terry Root.

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-awarded 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 almost every state.

What is 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 in the northeastern United States. In much of Florida and southern Texas and Louisiana, the country’s extreme southern areas, the satellites show spring coming a tad later; 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. EDT 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 late last year they created a National Phenology Network at the U.S. Geological Survey to monitor the 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 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 creatures could starve.

Also, plants that bud too early can still be destroyed 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 neighbourhood 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 University of Notre Dame biology professor Jessica Hellmann. — AP

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