Warming is driving Southern butterflies further north; called 'canaries the coal mine of climate'

Butterflies from the Southern U.S. that were rare in the Northeast are now appearing there more frequently as a result of climate change, according to a Massachusetts Butterfly Club study published in the journal, Nature Climate Change. Subtropical and warm-climate butterflies showed the sharpest population shift. These species were rare or absent in the Northeast as recently as the 1980s, Julia Whitty of Mother Jones reports. (Wikipedia Commons photo by Thomas Bresson: Giant swallowtail butterfly)

While Southern butterflies are moving north, more than 75 percent of species north of Boston, are rapidly declining, the study found. Species that overwinter as eggs or larvae are disappearing fastest, which suggests warmer winters may be the cause, Whitty reports. "For most butterfly species, climate change seems to be a stronger change agent than habitat loss," lead study author Greg Breed said. Habitat protection is a major step in protecting butterflies, but Breed said that for many species, "Habitat protection will not mitigate the impacts of warming."

The Butterfly Club is a citizen scientist group that for the last 19 years has logged butterfly species and numbers during 20,000 expeditions through Massachusetts. "Their records fill a crucial gap in the scientific record," Whitty reports. "Butterflies are turning out to be the canaries in the coal mine of climate warming." (Read more)