Human Flower Project

Walden Pond as Megaphone

Climate change isn’t only affecting the Amazon rainforest and polar ice cap; it’s changing Thoreau’s woods.


Students of biologist Richard Primack keep track of plants’ flowering times in Concord, Mass.

Photo: Boston University

Among flowers (and who knows how many other forms of life) flexibility may be the key to the survival.

A newly published study led by Boston University’s Richard Primack has been tracking the phenology of Plymouth, Cambridge, and Concord, Massachusetts,  a region of the U.S. with a long (for this country) and distinguished paper trail. At Walden Pond in Concord, where literary naturalist Henry David Thoreau lived from 1845-1847, there’s been an unbroken record of bird migrations and plant colonies, invaluable for scientists who hope to chart species and climate change.

That’s just what Primack and his colleagues have been doing for the past four years. Trapping warblers, dating aster blooms, counting buttercups, they have been studying how the undeniable warming in the local climate is changing life here.

imageTemperatures in the vicinity of Boston have risen on average 5 degrees F. over the past 150 years

Chart: Boston University

Spring, they say, arrives a solid week earlier than in Thoreau’s time, and some plants have adjusted their flowering accordingly.

“Species whose flowering time are not responsive to changes in temperature are decreasing in abundance,” their study found. The plants that could track short-term temperature changes and whose flowers opened earlier over the long term “fared significantly better under recent warming trends,” meaning there were more of them.

Mustard and knotweeds have been among those plants that have adapted fastest to rising temperatures; some of the most beloved local wildflowers, “lilies, orchids, buttercups, violets, roses, dogwoods, and mints,” haven’t shown such flexibility, and their numbers are declining.

“Some 27 percent of all species Thoreau recorded in the mid-19th century are now locally extinct, and another 36 percent are so sparse that extinction may be imminent.”

imageBird’s foot violet, one of many vanishing wildflowers that hasn’t adjusted its flowering time to warmer temperatures

Photo: Boston University

As a human-flower project, Primack’s research is brilliantly designed. Not only has his team made good use of a detailed botanical archive, it also makes a powerful case that climate change – rather than habitat disruption or some other cause—explains the changes in wildlife patterns, because most of this area has been federally protected.

And as Walden Pond is about as close to a sacred place as one finds in the U.S., an aura of significance shudders about the Massachusetts research findings. These aren’t just any violets dying. They’re Thoreau’s violets.

Posted by .(JavaScript must be enabled to view this email address) on 10/28 at 04:18 PM


Glad you wrote about the NYT article (I did too -  Your essay title is smartly accurate.

Posted by Georgia on 10/29 at 10:39 AM
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