Monarch butterfly disappearance is a new canary in the coal mine

Derrick Jackson

Thursday, Oct. 10, 2013 | 2 a.m.

Andrew MacBlane has never taken monarch butterflies for granted. When he was 7, he spied an odd object hanging down from a plant in his grandmother’s garden outside of Pittsburgh. He did not know it was a chrysalis until one day when a monarch floated around the flowers.

“We caught it, my grandmother read to me from Peterson Field Guides and then we let it go,” MacBlane said. “I’ve been fascinated with other butterflies, bees, lightning bugs, anything I could get my hands on ever since.”

MacBlane, now 33 and a Mass Audubon naturalist at the Boston Nature Center in Mattapan, is certainly not taking monarchs for granted this summer. The butterfly garden in front of the center, which is swarmed by up to a dozen monarchs in a normal year, has been almost completely unvisited. It is part of the worst year for the butterfly in the 20 years that records have been kept. From Mattapan to Minnesota and up through Maine and Canada, scientists and volunteers are recording record low numbers.

The monarch is the only North American butterfly known to migrate. Its journey and metamorphosis are among the most amazing in the world, as no individual butterfly makes the whole round trip. In the spring, butterflies depart from Mexico for Texas, where they breed and die. Successors begin fanning out over the United States east of the Rockies, repeating the reproductive cycle several times along the way. A late-summer monarch in New England may represent the third or fourth generation that year.

But today, an assault awaits the butterfly at almost every stop. Its only food, milkweed, has disappeared as Midwestern grasslands become food and biofuel farmland and agricultural fields are essentially sterilized for corn and soybean crops that are genetically modified to resist pesticides. Suburban development and the increasingly extreme weather accompanying climate change, particularly heat and drought, are taking a further toll.

The combo adds up to a wintering monarch population that has crashed from an average of 350 million to 60 million. They congregate in one forest in Mexico. Their colonies once occupied up to 52 acres but are now down to 2.94 acres, according to the Mexican government and a consortium of environmental groups, including the WWF. Monarch researchers fear that if the acreage falls below 2.5, it may be difficult for the butterfly to recover to previous populations.

Some environmental groups are urging people to plant milkweed where they can. Researchers are beginning to question more loudly the carpet-bombing of commercial agricultural fields with pesticides. International efforts to halt logging are ongoing. But major efforts to save the butterfly probably will not take off until the average person realizes what is disappearing.

The monarch’s place in the natural world can be likened to that of other creatures whose plight has increased public support for preservation, such as bald eagles, osprey or polar bears. “You could maybe call them the bald eagles of butterflies,” MacBlane said. Perhaps if we think of them that way, mere awe of the majestic monarch will metamorphose into an effort to save it.

Derrick Jackson is a columnist for The New York Times.