WASHINGTON - It has to do with brown-headed cowbirds and clear-cut forests, lilacs and wildfires, vineyards in the Rhine Valley, marmots, dandelions, tadpoles, cherry trees around the Tidal Basin in Washington and musty old records stuffed in shoe boxes in people's closets and stacked on museum shelves.

Satellite photo composite: “Land surface phenologies across CONUS in 2000 revealed by hree AVHRR biweekly composites.” From USA National Phenology Network (USANPN) As scientists track global warming, they're using sometimes centuries-old data to assess its impact on plants, animals, insects, fish, reptiles and amphibians. Increasingly, they're discovering that it can take only one seemingly insignificant change to disrupt an entire ecosystem.

"People talk about a 1- or 2-degree rise in temperature and it's inconsequential to us. Who cares?" said Greg Jones, an environmental studies professor at Southern Oregon University who's been studying wine grapes. "But in an ecosystem it can have dramatic effects."

As the study of phenology, or life cycles, attracts growing attention, researchers are turning more and more to citizen scientists for help.

Since 1954, more than 1,000 people nationwide have monitored lilacs, recording when they first develop leaves, buds and blossoms in a program that started in Montana and is now part of the National Phenology Network. The data now can be submitted online.

Another 3,500 or so people are monitoring 4,500 different plants as part of Project BudBurst, another online program. Eventually those involved in the project would like to have 40,000 people tracking plants, shrubs and trees from kinnikinick to chokecherry and wheat to Western columbine.

"The biggest hit has been dandelions," said Jake Weltzin, a scientist with the U.S. Geological Survey who's the executive director of the National Phenology Network. "Everyone cares about dandelions."

Besides scientists and professional land managers, kindergartners, master gardeners, farmers, fishermen and bird, frog and butterfly watchers have participated. Weltzin said that every time he spoke with a garden club, about one in every five people who attended had detailed records tucked away on their plants, trees and shrubs.

Next year, the phenology network is launching a program to monitor wildlife and track such things as bird, fish and mammal migration.

"It's easy to observe when the plants in your garden flower or when the birds arrive at the feeder in your yard," said Abraham Miller-Rushing of the Wildlife Society.

Stored in cabinets at the University of Washington's Burke Museum are 12,000 file cards dating to 1955. The cards, according to curator Sievert Rohwer, provide a gold mine of information on the birds of the Pacific Northwest. The museum receives hundreds of cards a year from people who are tracking more than 100 species of birds. The museum unsuccessfully sought a National Science Foundation grant to organize the information online.

"It's a critical database that is enormously valuable," Rohwer said.

For instance, Rohwer said the records showed that brown-headed cowbirds were somewhat rare in the Northwest in the 1960s and 1970s because the region was too forested. "But now they are everywhere," he said.

Technically, phenology is the study of the seasonal timing of plant and animal life cycles, including such things as animal and bird migrations, emergence from hibernation and blooming, leafing and flowering. Over the past 10 years it's increasingly become a mainstay in the study of climate change, as life cycles are thought to be among the most sensitive to global warming.

Using data from official and unofficial sources, scientists say that spring, on average, is arriving roughly a week earlier than it did 50 years ago. That's caused ripple effects in natural ecosystems. For instance, if plants bloom earlier, insects and birds must adjust. Some species may respond better than others. Those that don't could disappear.

"It's clear changes in phenology are an early warning sign of climate change," said Daniel Schindler, an associate professor at the University of Washington's School of Aquatic and Fishery Sciences.

Using records dating to 1784, Southern Oregon University's Jones said that bud break for wine grapes in Europe's Rhine Valley was coming three weeks earlier than it did 50 years ago. Pests such as mites and aphids have to adjust to the new schedule, as do the ladybugs that eat them. Jones said the real problem, however, might be that the grapes were maturing earlier and had to be picked in the heat of late summer. That could affect quality. Wine grapes are best when they're harvested in fall temperatures.

Records for wine country in California, eastern Washington state and elsewhere in the United States are much sketchier. Even so, Jones said that the "same thing we are seeing in Europe we are seeing in the limited data here."

Perhaps the classic example of the impact of climate change on an ecological community is oak trees in the Netherlands, which are leafing out earlier. The winter moth caterpillars that feed on the leaves are coming out earlier. The pied flycatchers that eat winter moth caterpillars remain on the old schedule, however, as they migrate from central Africa to the Netherlands. In some areas, the populations of pied flycatchers have dropped 90 percent.

"There are similar stories everywhere," Miller-Rushing said.

The cherry trees in Washington, D.C., are flowering earlier, marmots in the Rocky Mountains are emerging earlier, butterflies are moving farther north and in some cases practically have become invasive species, and everything from prairie dogs to tadpoles and apples to peaches is being affected, Weltzin said.

Lilacs have been the star of the program so far, he said. They're a common plant, they grow almost everywhere and their life-cycle changes are easy to observe. As opposed to many plants, however, lilacs may be blooming later because of climate change. Weltzin said lilacs needed their winter sleep, and that the warmer and drier it was the later they woke up.

"It's very counterintuitive," he said.

In general, Weltzin said, if lilacs in the West bloom after May 20, it's going to be a major forest fire season.

"We need to know how all these organisms respond to climate change," Weltzin said. "We call it the pulse of our planet, or timing is everything."

ON THE WEB

National Phenology Network

Project BudBurst

Project BudBreak

U.S. Geological Survey

MORE FROM MCCLATCHY

Global warming blamed for tree death in West

Regulators ban fishing in Arctic as warming changes ocean ecosystem

Obama tells EPA to review rejection of state emissions standards