Those of us in the chilly Northeast might be cranking up the heat and praying for bursts of spring green, but for many plants in the eastern United States, spring is coming a little too soon.
Exceptionally warm weather in recent years has caused plants to flower earlier than usual. In fact they're flowering sooner than they have at any point in the last 150 years, according to a study published this week in PLOS ONE.
Researchers identified plants in Massachusetts and Wisconsin that bloomed three weeks earlier than they did when they were first observed, with some species of plants flowering up to six weeks earlier.
These early bloomers have a predictable culprit. In his interview with TakePart, Charles Davis, professor of organismic and evolutionary biology at Harvard and the study’s senior author says, “Early flowering times, as far as we can tell, are due to climate change.”
For now, many plants appear to be adapting to the rise in temperature. But botanists are questioning how long it will be before plants can no longer adjust to increasingly early spring temperatures. “Even things that are benefitting are shifting so much out of their normal schedule that they are missing common associations that they would have in nature, like primary insect pollinations, or primary dispersers that move their fruits and seeds around,” Davis says.
To conduct the study, Davis and his colleagues used—how cool is this?—data sets from Henry David Thoreau, poet and philosopher of Walden Pond, who recorded flowering times across Concord, Mass., in the mid 1800s, as well as information collected by environmentalist Aldo Leopold on flowers in central Wisconsin in the mid 1930s.
They compared these records to flowering times in 2010 and 2012, two recent years with unusually warm springs, and found a dramatic shift. Thoreau saw highbush blueberry flower in the middle of May, while Davis observed the same plant flower on April 1st 150 years later.
Other researchers are seeing similar patterns in other areas of the country.
“Two thousands twelve was a record early flowering event in the Rocky Mountains,” says David Inouye, a biology professor at the University of Maryland who studies how climate change affects plants living at high altitudes. “We are seeing warm spells in early to mid spring that trigger plants to develop buds or flower, but then a hard freeze comes along and plants are lost.”
Some intrepid farmers and gardeners have begun mitigating frost damage with smudge pots, windmills, and even electric heaters to keep their crops from freezing during “false springs.” In the future, Inouye said, there may be a kind of assisted migration, in which people move seeds and plants northward as the temperature warms so that plants can continue to grow in the climate zone to which they are adapted. But for wildflowers in a place like Colorado, he said, there is not much we can do in the short term.
Charles Davis hopes that early flowers will help people realize how climate change is affecting our planet in ways that hit a little closer to home.
“In New England we are seeing this right outside our doors. It’s brought the problem home to us in ways we have never seen before,” Davis tells TakePart. “We’ve heard about polar bears and melting ice caps for years. But these are places and plants that we know and love.”
Have you noticed this change in your the areas around your own home? Let us know in the Comments.