The Butterfly Effect: Global Warming Changes Butterfly Habitat and Behavior

Saturday, June 12, 2010 by: M.Thornley
Tags: global warming, butterflies, health news

(NewsTarget) Butterflies inhabit every continent except Antarctica. Flitting from flower to flower, they assist in pollination. People are awed by their fragile beauty but more importantly, butterflies indicate the health of the environment. Cold-blooded, butterflies are dependent upon temperature, just as are rodents, birds, frogs and other insects. Measuring butterfly response to warming temperature helps researchers all over the world gauge the effect of climate change, and researchers are finding that butterflies are seeking new habitat to find the temperatures they need.

In an article titled, "Butterflies Across Europe Face Crisis as Climate Change Looms," researchers warn that Europe will lose much of its biodiversity due to global warming as indicated by a study of butterfly distribution conducted by the Climatic Risk Atlas of European Butterflies, which involves hundreds of European scientists. One of the authors of the study, Dr Josef Settele, said: "The Atlas shows for the first time how the majority of European butterflies might respond to climate change. Most species will have to shift their distribution radically."

In Great Britain, declines in butterflies led researchers to consider saving the butterflies by moving them to cooler areas. Researchers at Durham University caught Marbled White and Small Skipper butterflies in North Yorkshire, and transplanted them to County Durham and Northumberland where, eight years later, the species were found to be thriving. Professor Brian Huntley of Durham University hailed this experiment in "assisted colonisation" as a possible role in wildlife conservation.
This idea is also being pondered among conservation biologists in the United States. Known as "assisted migration" moving a butterfly to a more congenial place presents many problems. Will a butterfly fit in the new home? What about the plants it depends on or other aspects of its habitat? Which butterflies should be moved?

At UC Davis, California, Arthur Shapiro, professor of evolution and ecology for 35 years, monitored fixed routes for butterfly populations twice a month at ten sites from Suisun Bay to the Sierra Nevada in central California, accumulating data on over 150 species of butterflies. On April 18, 2005, Shapiro counted 21 species and 378 individual butterflies in Gates Canyon near Vacaville.
On April 18 of the following year, 2006, Shapiro counted just 10 species and 43 individual butterflies. "Butterflies," Shapiro notes in 2010, "are being hit hard by the combination of lower temperatures and habitat loss."

"I used to be able to walk 15 minutes from my lab and find common sootywing larvae. Now I know of only one permanent colony in the whole county," Shapiro says. "Butterflies that were once considered utterly common, including willow hairstreak, large marble and West Coast lady, are going into a tailspin."

Shapiro reported three major findings: Butterfly diversity is being lost at sea level but is increasing at tree line as butterflies migrate to cooler areas. High elevation butterflies are being lost since they cannot move higher. When an area changes from rural to urban or suburban, the greatest butterfly losses occur.

At the University of Melbourne, Australia, butterflies are found to be emerging 10 days earlier than they did 65 years ago. This led researchers to establish, for the first time, a causal link between "increasing greenhouse gases, regional warming, and the change in timing of a natural event." Researchers found that air temperature around the city of Melbourne has been increasing incrementally every decade, and, over the 65 year period, the Common Brown butterfly (Heteronympha merope) has shifted its emergence date 1.6 days earlier per decade.

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About the author

M. Thornley enjoys walking, writing and pursuing a raw vegan diet and lifestyle.