Grasshopper plagues: agricultural nightmare or ecological boon?

 

In early June, meteorologists at the National Weather Service in Albuquerque, New Mexico, were puzzled: There was a big splotch on the radar that didn’t look like any weather system they’d ever seen. Maybe their software had a bug?

Turns out, the dark green blob hovering over Albuquerque wasn’t a software glitch at all but a giant swarm of grasshoppers. John Garlisch, an agricultural extension agent at New Mexico State University, told Modern Farmer that the state’s dry winter allowed more grasshopper eggs than usual to hatch this spring, and the ongoing drought has caused a dearth of fresh growth on rural rangeland, forcing the swarm to take flight in search of greener pastures. The well-watered gardens of Albuquerque must’ve looked mighty appealing.

By now, the grasshoppers have mostly died of natural causes or been eaten by cats, says forecaster Brent Wachter of the National Weather Service. But this summer’s incident raises the question: As climate change continues to impact weather patterns across the West, will grasshopper swarms big enough to show up on Doppler radar become a more regular concern? And if so, how concerned should we be?

To find out, I called population ecologist Gary Belovsky, who’s been studying grasshoppers in western Montana for 37 years. He's currently researching how climate change affects grasshopper outbreaks. If you’re looking for a simple, straightforward answer, though – something along the lines of “climate change causes drought and drought causes more grasshoppers” – look elsewhere. While drought can indeed increase grasshopper populations for the short term, the picture Belovsky paints over the long run is far more complex.

In the National Bison Range where he conducts his research, summers have grown consistently drier and hotter over the last century. Yet the month of June has gotten cooler and wetter – and since that’s when most plant growth happens, overall plant production has increased. That gives grasshoppers more food to eat, which in turn increases their numbers.

But under the withering heat of summer, plants also turn brown more quickly, so without fresh leaves to nosh on, grasshoppers can thrive for a period but ultimately don’t live as long. “We’re trying to figure out the ecological impact of that,” Belovsky says. “If they don’t live as long, do they lay as many eggs? If they don’t lay as many eggs, can they keep up their populations?"

Did he just say keep up grasshopper populations? Surely we don’t want more grasshoppers?

IMG_0735.JPG
A grasshopper in the author's backyard in Paonia, Colorado. Photograph by the author.

Well, it depends. Our understanding of the pests has come a long way since 1874, when an outbreak of Rocky Mountain locusts ate their way through the West, devouring crops, clothing, horse harnesses – “everything but the mortgage,” farmers griped. Grasshoppers’ dead bodies were so thick their guts clogged railroad tracks and stopped the trains.

Just 30 years later, the Rocky Mountain locust apparently went extinct. No one knows exactly why or what the biological consequences were, but generally, the loss was counted as a win. Since then, smaller outbreaks of other grasshopper species have continued to periodically devastate Western rangelands, and we've deployed ample pesticides to keep them in check.

Now, Belovsky’s research indicates that grasshoppers may actually be essential in certain ecosystems. “No doubt there are times when grasshoppers become a serious economic threat to ranchers, but we’ve also found there’s particular grasslands where the grasshoppers are absolutely crucial to maintaining the nitrogen cycle,” he explains.

Grasshopper outbreaks may help some Western ecosystems the same way wildfire does: by knocking them back to an earlier developmental stage and allowing new growth. In the short term, a huge swarm of grasshoppers mowing down fields is detrimental to cattle, sheep and wildlife. “But if you take a longer perspective, heavy consumption by grasshoppers may change the plant community and bring in new species that are more nutritious to wildlife and livestock,” Belovsky says. That leaves rangeland managers with a conundrum: to spray, or not to spray?

It's a question they may soon have to face. Though it won't be this year, West is due for the kind of big, multi-state outbreak we haven’t seen in decades. “It’s a repeating event,” Belovsky says. “And it’s going to happen again.”

Krista Langlois is an editorial fellow at High Country News. She tweets @KristaLanglois2.

High Country News Classifieds
  • PART-TIME EXECUTIVE DIRECTOR
    Mitchell Museum of the American Indian Location: Evanston, IL Salary Range: $45,000 @ 24 hours per week. send resume: [email protected] www.mitchellmuseum.org
  • OUTDOOR PROGRAM - ASSISTANT DIRECTOR
    St. Lawrence University seeks to fill the position of Assistant Director in the Outdoor Program. To view the complete position description, including minimum qualifications required,...
  • PUBLIC LANDS DIRECTOR
    Job Announcement Conserve Southwest Utah is seeking a dedicated advocate for conservation and public lands Public Lands Director a "make a difference" position Conserve Southwest...
  • FOR SALE
    Yellowstone Llamas Successful Yellowstone NP concession Flexible packages
  • DIRECTOR OF DEVELOPMENT & MARKETING
    Grand Staircase Escalante Partners is seeking a full-time Director of Development & Marketing. This is a senior position responsible for the development of all marketing...
  • LEGAL DIRECTOR
    The Legal Director will work closely with the Executive Director in cultivating a renewed vision at NMELC that integrates diversity, equity, and justice. Black, Indigenous,...
  • VICE PRESIDENT, LANDSCAPE CONSERVATION
    The Vice President for Landscape Conservation leads Defenders' work to promote landscape-scale wildlife conservation, focusing on four program areas: federal public lands management; private lands...
  • NOVA SCOTIA OCEAN FRONT
    Camp or Build on 2+ acres in Guysborough. FSBO. $36,000 US firm. Laurie's phone: 585-226-2993 EST.
  • COMMUNITY FORESTER
    The Clearwater Resource Council located in Seeley Lake, Montana is seeking a full-time community forester with experience in both fuels mitigation and landscape restoration. Resumes...
  • GUNNISON BASIN ROUNDTABLE
    The Gunnison Basin Roundtable is currently accepting letters of interest for ten elected seats. Five of the elected members must have relevant experience in the...
  • PCTA TRAIL CREW TECHNICAL ADVISORS IN WASHINGTON'S NORTH CASCADES
    Seasonal Positions: June 17th to September 16th (14 weeks) - 3 positions to be filled The mission of the Pacific Crest Trail Association is to...
  • WE'RE LOOKING FOR LEADERS!
    As we celebrate 50 years of great Western journalism, High Country News is looking for a few new board members to help set a course...
  • MEMBERSHIP DIRECTOR
    Job Announcement Job Title: Membership Director Supervisor: Executive Director Salary: Up to $65,000/year DOE Benefits: Generous benefits package — health insurance, Simple IRA and unlimited...
  • UTAH PUBLIC LANDS MANAGER
    Who we are: Since 1985, the Grand Canyon Trust has been a leading voice in regional conservation on the Colorado Plateau. From protecting the Grand...
  • EXECUTIVE DIRECTOR
    Executive Director Walker Basin Conservancy Reno & Yerington, NV Background The Walker Basin Conservancy (Conservancy) leads the effort to restore and maintain Walker Lake while...
  • WIND RIVER WRITERS AND PHOTOGRAPHERS RETREAT BY THE NATIONAL BIGHORN SHEEP CENTER
    Enhance your writing or photography skills with world-class instructors in the beautiful Wind River Mountains. All skill levels welcome. Continuing education credits available.
  • EARTH CRUISER FX FOR SALE
    Overland Vehicle for travel on or off road. Fully self contained. Less than 41,000 miles. Recently fully serviced Located in Redmond, OR $215'000.
  • ENVIRONMENTAL GEOPHYSICS
    identifies suspect buried trash, tanks, drums &/or utilities and conducts custom-designed subsurface investigations that support post-damage litigation.
  • SMALL FARM AT BASE OF MOUNT SHASTA, CALIF.
    Certified organic fruit/berry/veggie/flower farm. Small home, 2 barns (one has an apartment), and more. Approx. two acres just in the City limits. Famously pure air...
  • TAOS HORNO ADVENTURES
    A Multicultural Culinary Memoir Informed by History and Horticulture. Richard and Annette Rubin. At nighthawkpress.com/titles and Amazon.