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Tagging monarchs helps understand miracle of migration

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Anna Marie Lux
September 15, 2013

WHITEWATER--You can hear the excitement in their voices as Larry and Emily Scheunemann describe the fluttering crowd of monarchs in their clover field.

“We're really lucky,” Larry said. “We've heard how no one is seeing any monarchs this year, but we've had a good year for them.”

Earlier this month, the retired Janesville teachers netted and tagged 50 of the bright orange and black butterflies with adhesive dots, each the size of a baby's thumbnail.

Then they released the monarchs, insects drawn by some invisible force to the mountains of central Mexico in one of nature's unexplained miracles.

No butterflies anywhere on the planet migrate like the monarchs of North America. They are the only ones to travel 3,000 to 4,000 miles to get out of the cold to hibernate and to return north in spring.

Scientists still are trying to understand how monarchs wing their ways to winter roosts without ever having been there. The roosts among high-elevation fir trees are the same ones used by generations before them.

Tagging by the Scheunemanns and other citizen scientists helps researchers understand the timing and pace of the migration as the butterflies move south to southwest across the continent.

Each tag contains contact information, including a toll-free telephone number. Emily and Larry record when and where they tag the insects and file the information with Monarch Watch, a monarch conservation and research program based at the University of Kansas.

Six monarchs they tagged in the last four years have been recovered in Mexico.

“You think that no one will ever find one of our butterflies in the million or so that go to Mexico,” Emily said. “But they do.”

“The thought of a butterfly traveling all that way is overwhelming,” Larry said. “Just think of the tremendous distance they cover, fluttering here and there.”

Monarch numbers are down dramatically across the country but not at the Scheunemann home.

Their 30-acre oasis is lush with nectar-producing native plants, including New England asters, purple coneflowers and butterfly weed. Since moving to their rural Whitewater farm in 1988, Emily and Larry have learned what to plant to attract a healthy menagerie of insects and wildlife.

“We've gotten much better at it,” Emily said. “The plants are not just for monarchs but for all butterflies. If everyone planted something in their yard of value to the insects, they could help monarchs and other butterflies.”

In the future, what home gardeners such as the Scheunemanns plant may be critical to the monarch's survival.

Chip Taylor is a professor of ecology and evolutionary biology at the University of Kansas. He started Monarch Watch and has tracked monarch populations for more than 20 years.

“This will probably be the smallest migration we have ever recorded since 1992,” he said. “In turn, it will probably lead to the smallest overwintering population in Mexico ever on record.”

A perfect storm of events has caused the dangerous decline.

The summer drought of 2012 and excessive heat resulted in low monarch reproduction in the United States. As a result, the overwintering population in Mexico dropped by 80 percent. When the butterflies migrated into southern states this spring, they ran into low temperatures, which caused the first generation to develop slowly. The monarch cycles through three to five generations during the breeding season. By the time they reached the Midwest, they experienced a cooler than normal summer, which limited reproduction of the generation that migrates to Mexico.

In addition to the weather, Taylor said new agricultural practices are taking a toll on monarchs and beneficial insects that share the same habitat.

Historically, the U.S. Corn Belt produced half of the monarchs that migrate to Mexico. But milkweed, upon which monarch caterpillars feed, is disappearing from corn and soybean fields because of increased use of herbicides on herbicide-tolerant crops. The use of Roundup-ready soybeans, genetically engineered to resist the herbicide glyphosate, has resulted in the loss of at least 100 million acres of monarch habitat in agricultural fields since 1997, Taylor said. Also, increased demand for bio-fuels has prompted farmers to put about 25 million acres of marginal land into production, often eliminating habitats filled with milkweeds and nectar plants.

Frequent mowing of roadside ditches destroys the plants monarchs need to survive, as well, Taylor said.

In Mexico, the monarchs face more threats. Illegal logging may deplete their wintering forests, and unregulated ecotourism is disturbing their winter refuge.

But Taylor is worried about more than the monarchs.

“I am concerned about the pollinators that share the same habitat with the monarchs,” he said. “About 70 percent of our vegetation out there requires pollination for fruits and berries. We lose all the bees, beetles and flies at our peril. It is serious to lose monarch butterflies because it tells us we are losing a lot of other things as well.”

The Midwest is “under enormous pressure to convert land for human purposes,” Taylor said. “We have to recognize that our cities, towns and little communities need to become refuges for wildlife. We have to repurpose our gardens for wildlife.”

Even in a bad year, Emily and Larry show that if you plant it they will come.

They are members of the Wild Ones, a group that stresses the value of planting native flowers and forbs for beneficial insects and wildlife. Last weekend, they invited the public to be part of their monarch-tagging program. They hope they inspired a few visitors.

“People were so excited about what they were seeing,” Emily said. “I wouldn't be surprised if they went home and figured out how to plant things around their homes so they can have monarchs, too.”

Taylor hopes the monarch migration does not become a memory.

“The real question is how many years will it take for the monarchs to come back,” he said. “That's where it gets real iffy. We are doing what we can to get the message out.”

Anna Marie Lux is a columnist for The Gazette. Her columns run Sundays, Tuesdays and Thursdays. Call her with ideas or comments at 608-755-8264, or email amarielux@gazettextra.com.



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