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
  • EXECUTIVE DIRECTOR
    Forever Our Rivers Foundation is searching for a driven and creative leader to build a movement, conserving and restoring America's rivers by helping customers find...
  • DEPUTY DIRECTOR
    Friends of Cedar Mesa is hiring a Deputy Director/COO who will have the overall responsibilities of general program management, staff management, financial & budget management,...
  • CUSTOMER SERVICE ASSISTANT - (PART-TIME)
    High Country News, an award-winning media organization covering the communities and environment of the Western United States, seeks a part-time Customer Service Assistant, based at...
  • RURAL ACREAGE OUTSIDE SILVER CITY, NM
    Country living just minutes from town! 20 acres with great views makes a perfect spot for your custom home. Nice oaks and juniper. Cassie Carver,...
  • COMMUNICATIONS AND OUTREACH ASSOCIATE
    Communications and Outreach Associate Position Opening: www.westernlaw.org/communications-outreach-associate ************************************************* Location: Western U.S., ideally in one of WELC's existing office locations (Santa Fe or Taos, NM, Helena,...
  • OFFICE ADMINISTRATOR AND BOOKKEEPER
    Posted: July 19, 2021 Application deadline: August 27 or until position is filled. Western Colorado Alliance for Community Action is seeking a fulltime Office Administrator...
  • COMMUNITY ORGANIZER
    Posted: July 15, 2021 Application deadline: August 21, 2021 or until position is filled Western Colorado Alliance for Community Action is seeking three full time...
  • A FIVE STAR FOREST SETTING WITH SECLUSION AND SEPARATENESS
    This home is for a discerning buyer in search of a forest setting of premier seclusion & separateness. Surrounded on all sides by USFS land...
  • CARPENTER WANTED
    CARPENTER WANTED. Come to Ketchikan and check out the Rainforest on the coast, HIke the shorelines, hug the big trees, watch deer in the muskeg...
  • AUDIENCE ENGAGEMENT EDITOR
    High Country News (HCN) seeks an audience editor to attract and acquire new audiences and deepen engagement with them - in our newsletters, on our...
  • COMMUNITY MARKETER
    High Country News (HCN) is looking for a Community Marketer to build and strengthen relationships between HCN and other organizations and individuals, with the aim...
  • FINANCE & OPERATIONS MANAGER
    Job Announcement: Finance and Operations Manager Announcement date: July 16, 2021 Applications will be reviewed on an ongoing basis and first review will begin: August...
  • DEVELOPMENT DIRECTOR
    Job Announcement: Development Director Announcement date: July 16, 2021 Applications will be reviewed on an ongoing basis and first review will begin: August 9, 2021...
  • HECHO POLICY AND ADVOCACY MANAGER
    Hispanics Enjoying Camping, Hunting, and the Outdoors (HECHO) was created in 2013 to help fulfill our duty to conserve and protect our public lands for...
  • HECHO NEW MEXICO SENIOR FIELD COORDINATOR
    Hispanics Enjoying Camping, Hunting, and the Outdoors (HECHO) was created in 2013 to help fulfill our duty to conserve and protect our public lands for...
  • IDAHO STATE DIRECTOR
    The Wilderness Society is seeking a full time Idaho State Director who will preferably be based in Boise, Idaho. This position is part of our...
  • CAUCASIAN OVCHARKA PUPPIES
    Strong loyal companions. Ready to protect your family and property. Proven against wolves and grizzlies. Imported bloodlines. Well socialized.
  • DEPUTY DIRECTOR
    The Nature Conservancy in Alaska is dedicated to saving the lands and waters on which all life depends. For more than 30 years, TNC has...
  • STAFF ATTORNEY, CLIMATE AND ENERGY PROGRAM
    STAFF ATTORNEY POSITION OPENING https://westernlaw.org/career-opportunity-climate-energy-staff-attorney/ ************************************************** Position Title: Climate and Energy Program Staff Attorney Reports to: Climate and Energy Program Director Location: Helena, Montana; other...
  • STAFF ATTORNEY, WILDLANDS AND WILDLIFE PROGRAM
    STAFF ATTORNEY POSITION OPENING https://westernlaw.org/career-opportunity-wildlands-staff-attorney/ ************************************************** Position Title: Wildlands and Wildlife Program Staff Attorney Reports to: Wildlands and Wildlife Program Director Location: Portland or Eugene,...