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Early Bloomers
Audubon, March/April 2009
When naturalist Henry David Thoreau recorded his observations on the environment in Concord, Massachusetts, he probably never imagined his work would help scientists 150 years later understand their changing climate. Boston University botanist Richard Primack and Abraham Miller-Rushing, an ecologist with the USA National Phenology Network, deciphered Thoreau's scrawled notes of the first flowering dates during the 1850s. They also obtained the dates in Concord at the turn of the 20th century, and followed up with their own record keeping earlier this decade. Their data, published in the journal Ecology, show that the mean first flowering date for 43 plants moved up by a week: from May 14 in Thoreau's time, to May 10 in the 1890s, and to May 7 in recent years. Some species are blooming much earlier, such as the highbush blueberry (21 days) and the yellow wood sorrel (32 days). "The study almost certainly underestimates the change," Miller-Rushing says, because Thoreau recorded unusually warm years and because the study's final years were especially cold. Changing bloom dates will likely alter the interactions between flowering plants and pollinators like bees, potentially throwing the plants and animals out of sync and hindering their survival. "Climate change is not just affecting species in Canada or northern Europe," Primack says. "It's already affecting species in the eastern United States, and in Concord, one of the most central places in American consciousness."
View the article on the Audubon Magazine Web site.
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