In his book Walden, Henry David Thoreau chronicled, among other things, the plant species surrounding Walden Pond near Concord, Mass. Now his data is being used to show that many of those plants are no longer growing at Walden.
The decline in plant species doesn’t appear to be linked to modern development, as much of the land surrounding the pond has been left undeveloped, according to an Associated Press article. To explain why 27 percent of the plant species Thoreau documented are now gone and another 36 percent are in stark decline, researchers are pointing to warming temperatures—a 4.3 degrees Fahrenheit hike over the past century.
The plants having the hardest time surviving are those that can’t alter their blooming time, such as lilies and roses, or respond to temperature changes, such as orchids, dogwoods, buttercups, asters, violets and campanulas.