UM Research Identifies Cross-Boundary Solutions to Invasive Weeds

April 11, 2019

MISSOULA – Weeds don’t stop at fence lines and neither should solutions, according to research published this week in Nature Plants by an international team of 15 researchers, including the University of Montana’s Alex Metcalf.

Around the world, invasive plants spread and escalate management costs, despite exhaustive efforts by researchers, extension personnel and land managers. To address this growing challenge, Metcalf joined the team, which includes both natural and social scientists, to examine weed control through a cross-boundary lens.

Management techniques for invasive weeds primarily have been developed for individual landowners, but practices rarely look at how control from a collective perspective would improve overall weed management outcomes. The new paper is a call to action for scholars and practitioners to broaden their conceptualization and approaches to weed management, beginning by evaluating the “public good” characteristics of specific challenges and adopting solutions properly tailored to their social context.

“Traditional approaches to weed control have often ignored the scale, complexity and collective nature of the problem,” said Metcalf, an assistant professor in UM’s W.A. Franke College of Forestry and Conservation. “What we show with this work is that solutions will be more effective when guided by landscape-scale design principles that encourage cross-boundary cooperation.”

The study, published April 8, frames weed control as a social dilemma, where individual and collective interests do not always align.

“Social dilemmas often take on very different configurations,” Metcalf said. “For example, weed control is almost a classic ‘public good’ problem and requires very different approaches. Correctly classifying the world’s worst weed management challenges helps identify the right type of solution and give people the best chance at achieving their goals.”

The team applied a transdisciplinary approach to four pressing international weed management challenges: plant biosecurity (the protection of plant resources from alien pests through quarantine, port inspections and bulk treatment), weed seed contamination (crop seed sources that can contain weed seeds), herbicide susceptibility (resistant weeds) and biological weed control (classic efforts to deploy host-specific arthropods or pathogens).

“Solutions to these collective problems should be guided by four overarching principles,” Metcalf said. “Stakeholders must share common goals and commitments to contribute to control efforts, values must be shared or good working relationships must be established, individual contributions must be transparent, and resources must be pooled to support those least able to contribute.”

The team of researchers was led by Muthu Bagavathiannan, a Texas A&M University weed scientist, and Sonia Graham, a social scientist at the University of New South Wales, Australia, currently visiting the Autonomous University of Barcelona, Spain. The group plans to continue collaborations to advance weed management solutions in Montana and around the world.

Contributors include Bagavathiannan; Graham; Metcalf; Zhao Ma, Purdue University; Jacob Barney, Virginia Tech; Shaun Coutts, University of Sheffield, England; Ana Caicedo, the University of Massachusetts; Rosemarie De Clerck-Floate, Agriculture and Agri-Food Canada, Canada; Natalie West, the United States Department of Agriculture–Agricultural Research Service, Montana; Lior Blank, Agricultural Research Organization, Volcani Center, Israel; Myrtille Lacoste, The University of Western Australia and Curtin University, Australia; Carlo Moreno, The College of Wooster, Ohio; Jeffrey Evans, USDA-ARS, Illinois, now at Farmscape Analytics, New Hampshire; Ian Burke, Washington State University; Hugh Beckie, Agriculture and Agri-Food Canada, now with University of Western Australia.

Read “Considering Weed Management as a Social Dilemma Bridges Individual and Collective Interests” in Nature Plants online at


Contact: Alex Metcalf, assistant professor, W.A. Franke College of Forestry and Conservation, 814-574-6128,