Using historical data collected by famous naturalists and authors Henry David Thoreau and Aldo Leopold, scientists have linked early flower blooms to warm springs. This is the first time researchers have analyzed patterns in these two sets of data together. ?Enlarge
The warmest springs on record caused flowers to bloom at their earliest dates in decades at two historic sites, according to new research.Skip to next paragraph
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The findings, published online today (Jan. 16) in the journal PLoS ONE, show just how much climate change has altered ecosystems throughout the temperate areas of the United States. The study used 161-year-old data on flowering times from Henry David Thoreau's notebooks, as well as nearly 80-year-old data from the famous naturalist Aldo Leopold.
Scientists had previously described the Thoreau records but they hadn't combined the two naturalists' findings until now.
"Record warm temperatures (in 2010 and 2012) have resulted in record early flowering times," said study researcher Elizabeth Ellwood of Boston University. [8 Ways Global Warming Is Already Changing the World]
Henry David Thoreau was one of the most iconic figures of the 19th century. The famous naturalist and poet wrote the book "Walden" about his years living at idyllic Walden Pond in Concord, Mass. Starting in 1852 and at different points throughout his life, he also created the first "spreadsheets of flowering dates" for many well-known?flowers, including the wild columbine, the pink-lady slipper orchid and the marsh marigold, Ellwood said.
Similarly, the naturalist Leopold took detailed records of first flowering times at a site called "The Shack" in?wilderness near the Wisconsin River, starting in 1935.
"It's the iconic equivalent to Walden Pond for Wisconsinites," Ellwood told LiveScience.
While scholars knew of these flowering observations, many were scattered in different libraries and archives, and no one had systematically analyzed their patterns, she said.
Hotter springs, earlier blooms
To do so, Ellwood and her colleagues gathered all of?Thoreau's flowering records?from several archives. They then compared flowering dates with spring temperatures for 32 different flowering plants.