Worth Defending: Karner Blue

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All butterflies look dainty and delicate, but the strikingly beautiful and endangered Karner blue measures only an inch across — about the size of a postage stamp — and lives only about a week.

The beloved butterfly of novelist — and lepidopterist — Vladimir Nabokov, who “discovered” the species in 1862, Karner blues once covered the northern pine barrens and black oak savannas in clouds of blue from Maine to Minnesota. Now small, isolated populations persist only in Michigan, Minnesota, New York and Wisconsin — and in Indiana, New Hampshire and Ohio, where biologists reintroduced them after they went locally extinct.

Land development, fragmentation and fire suppression have made the Karner blue’s habitat some of the rarest in the world. In fact, the butterfly’s numbers dropped by 99 percent in the last century — with the majority of the decline in the last two decades.

Karner blues feed on the nectar of a variety of flowering plants, including rock cress, goldenrod and butterfly weed. As caterpillars, however, they dine solely on the leaves of the wild blue lupine, a perennial pea, which is endangered itself. Lupines thrive when wildfires burn away the trees and shrubs that shade open spaces. Today these fires are often supressed.

But thanks to protection under the Endangered Species Act, reintroduction of captive-bred Karner blues to the wild is proving successful in states where local governments and private landowners are working to improve habitat.

All this means the future is looking a little brighter for this brilliant blue butterfly.


Making a Difference
From wolves to butterflies, ranchers and farmers can play an important role in protecting wildlife — when they have the resources to help. Defenders consistently fights for species’ protection programs funded through the Farm Bill, which is the nation’s largest source of conservation funding. Some 70 percent of privately owned land in the country is used for ranching, forestry or agriculture, and nearly 40 percent of species needing ESA protection are found only on private lands.

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