Butterflies Not Coping Well With Double Whammy of Climate Change and Habitat Loss

dead butterfly photo

Photo via quijonido via Flickr CC

Butterflies are having a rough time of things thanks to climate change. That isn't necessarily news. But in the most comprehensive analysis to date of the factors impacting butterflies, UC Davis butterfly expert Arthur Shapiro found that habitat loss is providing a fatal punch to butterfly diversity. And surprisingly, it's the "junk" species (the pigeons of the butterfly world) that are getting hit the hardest.

Science Daily reports that the latest analysis on butterflies takes information from a 35-year database of butterfly observations made semi-monthly at 10 sites in north-central California. The database includes data on over 150 species, with habitats ranging from sea level to tree line.

After analysing the data, Shapiro and his team found that butterfly diversity is falling fast at sea level and is declining slowly or holding just stead at higher elevations. But when we hit the tree line, the diversity is actually going up as species move into higher elevations to escape the warming temperatures lower down. In other words, global warming is pushing butterflies higher. But for those species adapted to cold climates, global warming is taking its toll. For them, as Shapiro states, "There is nowhere to go except heaven."

"Butterflies are not only charismatic to the public, but also widely used as indicators of the health of the environment worldwide," said Shapiro, a professor of evolution and ecology. "We found many lowland species are being hit hard by the combination of warmer temperatures and habitat loss."

Those lowland species include "weedy" butterflies, and they're actually getting hit the hardest as more habitat is turned into cities and suburban developments. Even though they're more mobile in habitat than "non-weedy" butterflies, they're declining more rapidly.

"Some of the 'weedy' species have been touted as great success stories, in which native butterflies had successfully adapted to the changed conditions created by European colonization of California. That was the case for many decades, but habitat loss has apparently caught up with them now."

Butterflies are important pollinators. A decline in bee numbers is already an issue of serious concern, so to loose butterflies as well is especially disconcerting.

The online butterfly portal run by Dr. Shapiro states, "As of the end of 2006, Dr. Shapiro has logged 5476 site-visits and tallied approximately 83,000 individual records of 159 butterfly species and subspecies. This major effort is continuing and represents the world's largest dataset of intensive site-specific data on butterfly populations collected by one person under a strict protocol."

On this site you can click through and read specific information about the sites, species, weather data and so forth.

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