Butterflies on the Move

Caught in the Winds of Climate Change

by Michael J. Caduto


Summer arrives on sheer, silent wings that move with a flutter of color and lightness of being. Greeks once believed that a human soul came into the world whenever a butterfly emerged from its chrysalis. In parts of Asia, butterflies symbolize happiness and joy. Once, while traveling as a storyteller in the Highlands of Scotland, I learned the Celtic belief that the Wee Folk, the “Tuatha de Danaan,” can change into a butterfly to avoid being discovered by people. If anyone harms a butterfly, that person hurts one of the Wee Folk, an act that brings bad luck.


Back in the 1970s, the Butterfly Effect spun off from the concept of Chaos Theory, which attempted to reconcile the apparent randomness of the universe. The Butterfly Effect holds that the faintest movement of air caused when a butterfly flaps its wings in, say, Massachusetts, begins a series of interconnected events that can ultimately cause a hurricane in some distant place like Cuernavaca.


We now seem to be experiencing a reverse butterfly effect: If climate change heats up the Gulf Stream and contributes to warmer weather, and if it generates a greater number of hurricanes in the Gulf of Mexico, will butterflies stop flapping their wings in parts of New England? The answer is yes, and no.


In 2012 Elizabeth Crone, Ph.D. and Associate Professor at Tufts University—along with Dr. Greg Breed and Dr. Sharon Stichter—co-authored “Climate-driven Changes in Northeastern US Butterfly Communities,” which was published in Nature Climate Change.


“Climate is getting warmer,” says Crone. “Mobile species move to new areas that suit their climate needs, if there is no other limiting factor. Species from the south are becoming more abundant, and species from the north are less abundant, on average. Many are increasing their range northward, but some species may not be able to move north due to habitat needs and geographic boundaries.”


Between 1992 and 2010, shifts in population numbers and geographic ranges have been observed in 100 of the 116 species of butterflies studied. Those species for which climate has demarked the southern extreme of their range are shifting northward, especially in the warmest regions. Those living at higher elevations are more stable, but species found in the lowlands are decreasing rapidly. Research shows that these responses are specifically related to climate.


Frequent hurricanes and severe tropical storms associated with climate change are impacting Monarch butterflies, the only species that migrates long-distance to New England. Monarchs from eastern North America overwinter in the mountains of southern Mexico. Each spring they journey north, laying eggs on milkweed along the way. These eggs produce the next generation, which continues the migration north. Several generations are born before monarchs reach New England.


In recent years, Monarch populations have been about 1/18th of what they were less than 20 years ago. Says Crone, “Sometime around World War II when pesticides, herbicides and other chemicals became so prevalent, we may have started a shift in butterfly numbers overall.”


Whether or not you ascribe to the Zuni belief that butterflies can predict the weather, they are harbingers of how our environment will evolve in an era of climate change. In Buddhism, butterfly metamorphosis symbolizes the human capacity for transformation—to transcend self-centeredness and be guided by a sense of oneness with all beings. The myriad decisions we make each day determine the fate of these ephemeral denizens of the air.


SIDEBAR: What You Can Do


  • Visit the Vermont Center for Ecostudies online “Vermont Butterfly Survey” to report a sighting: val.vtecostudies.org/projects/vermont-butterfly-survey/
  • Make energy-use and lifestyle choices that reduce carbon emissions and slow climate change.
  • Create a butterfly garden of native plants for food and places to lay eggs, such as milkweed for monarchs.
  • Don’t use pesticides, herbicides and other chemicals that harm butterflies, bees, and other beneficial insects.
  • Maintain open spaces for butterflies to feed, rest and breed. Join Monarch Watch and plant a Monarch Waystation habitat: monarchwatch.org/waystations/
  • Get involved in land conservation to preserve critical areas and prevent butterfly habitat loss. Support conservation groups working toward these ends.
  • Inform others about what is happening with butterfly populations and encourage them to track butterflies and work for positive change.


DO JUST ONE THING: Pick one way you’re going to help Monarch butterflies.

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