Some Butterflies Doomed, Others Thrive, with Climate Change

The endangered butterfly has become an ideal  insect for scientists measuring the damage of climate change

A new study published in Ecological Entomology shows some species of butterflies adapt much better than others to warming temperatures, especially in mountain landscapes.

Which are most at risk? It appears butterfly species which emerge later in the year or fly higher in the different elevations of a mountain range in central Spain have evolved to reproduce in a shorter window of time, and as a result, may fare worse than those that emerge over a longer period of time.

“We’re already expecting localized extinctions of about one third of butterfly species, so we need to understand how climate change will affect those that survive,” says Javier G. Illan, with the Department of Forest Ecosystems and Society at Oregon State University.

Illan’s group of researchers working at Rey Juan Carlos University in Madrid studied flight patterns of 32 butterfly species for five years at different elevations in a Mediterranean mountain range. They noted the delays in flight dates that occurred as a result of elevation change.

Butterflies are ultra sensitive to climate change and therefore good models for understanding the broader scope of ecological effects linked to insects in terms of pollination and herbivory. In fact, their flight dates are said to be good indicators of future responses to climate change .

Meanwhile, the Brown Argus has defied the odds. The rare British butterfly with orange and white spots near its wingtips is thriving rather than disappearing as a result of extreme temperatures as predicted.

As reported by Scientific American, the insects are on the move and expanding their range northwards some 40 miles, according to the UK Butterfly Monitoring Scheme. This means they are no longer solely dependent upon a single plant species, the Rockrose, which grows on south-facing slopes and absorbs the warmth the butterfly’s caterpillars require.

The Rockrose plant’s choice is cool weather, hosting caterpillars on the underside of leaves on south-facing hillsides, but balmier summer conditions has prompted the butterfly to warm up to new plants such as the Dove’s Foot Cranesbill.

This ability to adapt and expand north shows promise for some species. But according to ecologists, large range retractions in the south cannot be counterbalanced by the expansions in the north. In fact, About ten percent of all of Europe’s butterflies face extinction due to climate change, along with loss of grassland habitat from intensive farming and abandonment of traditional farming in Europe, forest fires and the expansion of tourism.

The same culprits threaten 14% of dragonflies and 11% of saprophytic beetles, according to the European Red List report for the European commission. Among the species listed as critically endangered – the striking Madeiran large white butterfly not spotted on the island of Madeira in twenty years; and the Macedonian Grayling which has suffered habitat loss due to quarrying.

Recently, Richard Pearson, a scientist at the American Museum of Natural History, cited the Red List in a New York Times Opinion page, warning us that a mass extinction is afoot. Some 20,000 species of animals and plants around the globe are deemed high risks and such a rapid loss of so many has only occurred five times in the past 540 million years. Around 65 million years ago, the last mass extinction wiped out the dinosaurs.

Writing about the pending loss of life on the planet, Pearson, who is the author of Driven to Extinction: The Impact of Climate Change on Biodiversity, suggested “this should keep us awake at night.”

He also urged us to invest in ecosystem services considered public goods. “We need to put a realistic value on nature, and we need effective environmental legislation that protects entire ecosystems.”

Luanne Bradley

Luanne Sanders Bradley is the West coast Editor at EcoSalon and currently resides in San Francisco, California.