Ecologically Based Integrated Weed Management to Restore Plant Diversity

Project Overview

Project Type: Research and Education
Funds awarded in 2003: $121,750.00
Projected End Date: 12/31/2007
Matching Non-Federal Funds: $15,000.00
Region: Western
State: Montana
Principal Investigator:
James Jacobs
Montana State University

Annual Reports


  • Agronomic: corn, potatoes, grass (misc. perennial), hay
  • Animals: bovine, goats, sheep


  • Animal Production: grazing - multispecies, pasture renovation, range improvement, feed/forage
  • Crop Production: application rate management
  • Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research
  • Farm Business Management: whole farm planning, budgets/cost and returns
  • Natural Resources/Environment: biodiversity, habitat enhancement
  • Pest Management: biological control, competition, field monitoring/scouting, weed ecology
  • Sustainable Communities: partnerships, public participation, sustainability measures


    Management treatments for spotted knapweed were evaluated on two ranches in Montana from 2003-2006. Treatments assessed were sheep grazing, biocontrol, native seeding and tillage. Spotted knapweed and cheatgrass densities, and occurrence of all native and non-native species was recorded. Grazing by sheep showed the largest decrease in spotted knapweed densities. Surprisingly, densities of spotted knapweed did not decrease after the release of the weevil Cyphocleonus achate. Seeding of native grasses and forbs was not successful when broadcast without disturbance, or with light disturbance provided by sheep, but it was successful after shallow tillage where blue-bunch wheatgrass densities increased significantly and cheatgrass densities remained similar.

    Project objectives:

    Objective 1) Integrate weed management strategies on spotted knapweed infested rangeland to address the three causes of succession based on site conditions, whole-ranch management objectives, and available ranch resources.

    Objective 2) Conduct rangeland ecoassessments to determine the effects of ecologically based management on controlling spotted knapweed and restoring native plant communities.

    Objective 3) Determine the economic implications of incorporating ecologically based weed management into ranching systems.

    Objective 4) Conduct educational programs for ranchers and agency personnel on ecologically based whole ranch management and disseminate the results through field tours, the popular press, and the scientific literature.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.