Massachusetts: Changes at Walden Pond
by Frank Wolff
“It is astonishing how soon and unexpectedly flowers appear, when the fields are scarcely tinged with green. Yesterday, for instance, you observed only the radical leaves of some plants; to-day you pluck a flower.” -- Henry David Thoreau
Great Meadows National Wildlife Refuge is located in Concord, Massachusetts. The area was home to a dedicated naturalist in the mid-1800s. He built himself a house on 14 acres of woods on the bank of Walden Pond. He dutifully and diligently recorded the flowering times of hundreds of plants as well as the behavior of rabbits, red squirrels, mice, birds and other animals for six years.
Henry David Thoreau, 1856
Credit: Photo courtesy of The Thoreau Society Collection at the Thoreau Institute at Walden Woods
His name was Henry David Thoreau.
Thoreau provided an extensive array of data that has proven invaluable as a baseline for phenological research that continues today. Phenology is the study of events in nature that are influenced by climate and seasonal change.
A study conducted by Abraham J. Miller-Rushing and Richard B. Primack found that climate change is causing many plants to flower much earlier today than they did in the past. The two researchers used Thoreau’s observations, as well as the work of Alfred Hosmer, another naturalist who studied the ecosystem around Concord, as a comparison to their own modern-day observations. Their research concludes that in Concord, plants are now flowering seven days earlier on average than they did in Thoreau’s time.
But not all plants are equally impacted by climate changes. Some species have the ability to track seasonal temperature change and will flower earlier when temperatures are warmer. Other species don’t track temperatures as well, and will continue to flower at the same time every year—regardless of temperature variations. The ones that don’t track temperatures as well are more likely to suffer a decline in numbers; they also tend to be related to one another, so entire plant families are impacted.
Click "More" below to continue reading