In 1851, Henry David Thoreau started recording when plants flowered in Concord, Massachusetts, the scene of his Walden. Now, notes from more than 200 years ago are serving as the basis for a complex inquiry into climate change and evolutionary biology.
The New York Times reports that researchers from Boston and Harvard Universities used Thoreau’s detailed notes, which were the result of hours spent tracking 500 species, to map which plant species still exist. They could now find seven of the 21 types of orchids Thoreau documented.
In total, the researchers concluded that 27 percent of the species Thoreau documented have vanished, and 36 percent are found in such small numbers that they probably will not survive.
Data on Concord is leading to conclusions about the ecology of New England, and climate change more broadly. As Charles Davis, an evolutionary biologist at Harvard is quoted as saying, “Certain branches of the tree of life are being lopped off.”