RENEE MONTAGNE, HOST:
Those royally beautiful creatures, monarch butterflies, are declining in numbers, partly because a certain weed is disappearing, especially across the American Midwest. The monarch butterfly caterpillar depends on milkweed to survive. And that's something you can help with by planting milkweed, which is really a pretty flower in your garden. I know. I have lots of milkweed in mine and lots of monarchs. From member station KBIA, Sara Shahriari has more.
SARA SHAHRIARI, BYLINE: A late summer breeze is blowing across the lawns of suburban Jefferson City, Mo., and over a small garden next to an elementary school.
CAROL DAVIT: We're standing here next to this swamp milkweed, which is very robust, about 4 feet tall. And I'm seeing a small monarch caterpillar on the underside of one of the leaves.
SHAHRIARI: That's Carol Davit of Missouri Prairie Foundation. She helped create this native plant garden. The caterpillar is stuffing itself. Monarch butterfly caterpillars need milkweed. It's the only food they eat, and in less than two weeks, they grow to 2,000 times their original mass. Caterpillars hatched in the late summer and early fall are the longest-lived monarch generation. If they're born east of the Rocky Mountains and make it to adulthood, the deep orange and black butterflies take off along the monarch flyways that stretch for thousands of miles from Canada down through the U.S. and into Mexico, where they winter in the Sierra Madre Mountains. 2013 saw the lowest butterfly count there since recording began in the '90s. Conservation groups are now focusing on the lack of milkweed and its impact on monarch populations.
CHIP TAYLOR: One-point-five billion - we need that many stems out there. And that's going to take about 20 million acres of habitat restoration, which would - if we accomplish that - be the biggest restoration program that has ever been attempted.
SHAHRIARI: Ecologist Chip Taylor heads Monarch Watch at the University of Kansas in Lawrence. His offices are filled with hundreds of little plastic containers of monarch caterpillars snacking on a leaf paste and breeding butterflies batting their wings in net cages. Taylor says it used to be that farm fields were a great source of milkweed, but in the past decade or so, more targeted use of herbicides, edge-to-edge row crops and development resulted in dramatic milkweed loss. The Missouri Prairie Foundation is trying to stem that, as is Kansas-based Monarch Watch. It plans to distribute 300,000 milkweed plants next year.
In Iowa, the Tallgrass Prairie Center is encouraging farmers and large landowners to plant milkweed and other native prairie plants. Karen Oberhauser is with the conservation umbrella group Monarch Joint Venture. She says that while she doesn't see monarch extinction as an imminent threat, the shrinking population puts the butterflies' spectacular migration at risk.
KAREN OBERHAUSER: The eastern North American migration could disappear to the point that it's not really noticeable. I mean, there might still be some monarchs doing it, but it would disappear as an incredible natural phenomenon.
SHAHRIARI: The need for diverse native plant landscapes was highlighted this year when the federal government released a national strategy to promote the health of honeybees and other pollinators. People looking to plant milkweed can turn to local native plant nurseries or conservation groups for help. It's uncertain, though, whether enough milkweed and other native plants can be planted to reverse monarch population loss and preserve the butterflies migration for future generations. For NPR News, I'm Sara Shahriari in Columbia. Transcript provided by NPR, Copyright NPR.