Monarchs need better pit stops on their epic journeys
by Susan Cosier
Last spring, ecologist Mary Galea got her hands dirty in a narrow clearing under some power lines in Youngstown, Ohio. She planted violet asters, golden Alexanders, and magenta bee balm, a few native, commonly found flowers. The plants added a burst of color to the green, grassy stretch, but that was just a bonus. The real draw, Galea hoped, would be the plants’ nectar. Over the summer, field researchers watched the garden of wildflowers and noted the pollinators — particularly monarch butterflies — that came for a visit.
In the past 25 years, monarch numbers have taken a nosedive, plummeting more than 90 percent due primarily to habitat destruction. The butterflies migrate back and forth across North America, fluttering south to Mexico for the winter and north as far as Canada in spring and summer. The round-trip journey spans three butterfly generations or more, and to make it, they need plants: those that provide nectar to fuel them and those that help them make more monarchs. Milkweed is the only plant on which monarchs lay eggs and is crucial to the species’s survival.
Galea’s efforts are part of an experiment called Monarch Wings Across Ohio, which aims to identify the flowers monarchs prefer to feast on. Last year, Galea and volunteers tried out 20 types of flowers and some milkweed on 16 different plot types, including public parks, a farm, and a former golf course. In coming years, the data generated from monitoring these study sites will help inform Ohio’s backyard gardeners and land managers about which types of vegetation give butterflies their biggest boost on the midwestern leg of their trip.
Galea’s project, part of the Pollinator Partnership, is just one of many looking at how we can revive monarch populations across the United States. The plants Galea and others are growing could prove critical to monarch populations in Ohio. Real success, however, won’t rely only on the greenery in our backyards, parks, and roadsides; we’ll also have to address what chemicals we spray on farm crops.
Once upon a time, milkweed grew naturally on farms, between fields of corn and soybeans. But farmers, under pressure to increase their yields, plowed fallow fields and started growing genetically modified crops designed to resist the powerful herbicide glyphosate (marketed as Roundup). Knowing these “Roundup ready” crops could withstand widespread application of the herbicide, farmers would spray entire fields with the chemical instead of targeting their crops directly. Now, native plants, such as milkweed, die right along with the unwanted weeds.
As the milkweed went, so went the monarchs. By some estimates, the amount of milkweed along the monarchs’ midwestern path fell nearly 60 percent between 1999 and 2010. And we’re still losing one to two million acres of habitat a year, thanks to development, over-mowing, and pesticides, says Chip Taylor, a prominent monarch researcher at the University of Kansas and head of Monarch Watch.
“We’re in a position now where we have to run twice as fast as we possibly can just to keep up with habitat loss,” says Taylor. In the case of the butterflies, “running” means planting as much habitat as possible — and preventing its destruction.
To that end, myriad entities have stepped in to help. States and the federal government, nonprofits, and academics have formed several groups focused on saving the butterflies. Monarch Joint Venture, for example, has helped fund Galea’s work as well as a citizen science monitoring project in Texas, research into exotic milkweeds and the spread of disease in monarchs, and more than a dozen other initiatives. Last year, with financial backing from the National Fish and Wildlife Foundation and Monsanto (the company that produces Roundup), the U.S. government launched the Monarch Butterfly Conservation Fund, which aims to protect and increase monarch habitat. For its part, NRDC (onEarth’s publisher) is working with the Illinois Tollway Authority to plant milkweed along 280 miles of highway in the state.
Anyone who plants milkweed in their backyard is going to help, too, says Sylvia Fallon, director of NRDC’s wildlife conservation project, but we also need to get more milkweed on larger tracts of land and around farmers’ fields.
Current efforts to improve farm soil health and reduce runoff may do just that. Lisa Schulte-Moore, an ecologist at Iowa State University, and other scientists began testing the benefits of strategically planting prairie strips — areas of restored prairie — nearly a decade ago. When they converted as little as 10 percent of row-cropped field to perennial prairie, they reduced the amount of soil loss by 95 percent, phosphorus loss by 90 percent, and nitrogen loss by 85 percent, compared with land kept completely in row crops. These strips of wildflowers, legumes, sedges, and native grasses also coax pollinators — including many a monarch — to drop in. Schulte-Moore and her team have introduced 150 acres of prairie strips to date, and farmers are keen to add more, all of which bodes well for butterflies.
How those prairie strips will hold up amid high levels of pesticides is still unknown. In order for programs like Schulte-Moore’s to help monarchs, the government has to do its part to address rampant pesticide use on farms, says Fallon. The feds have yet to limit pesticide use on fields or even to encourage farmers to go easy on how much they administer, so in February 2015, NRDC sued the U.S. Environmental Protection Agency for its lack of action in tackling the glyphosate threat.
Of course, glyphosate isn’t the only problem pesticide out there. While glyphosate is a very effective weed killer (and milkweed killer), some weeds have developed a resistance to it. To get rid of those pesky survivors, farmers also spray 2,4-D or atrazine, which aren’t good for butterflies or their caterpillars either.
Schulte-Moore’s team is now working on 25 commercial farms and with landowners who apply various pesticides to varying degrees to see how prairie strips fare under different conditions and whether they’ll provide high-quality habitat for monarchs.
Agricultural lands cover a lot of ground in the middle of the country, and prairie strips can give a little back to monarchs and other native pollinators, much like Galea’s work could provide hospitable hangouts on smaller plots. And that’s what we need: the best pit stops possible so these black and orange beauties can rest, eat, lay some eggs and get back on their way.
Originally published at www.nrdc.org/onearth on April 27, 2016.