Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies

In response to the decline of critical pollinators, including butterflies, a presidential memorandum entitled, “Creating a Federal Strategy to Promote the Health of Honey Bees and Other Pollinators,” established the Pollinator Health Task Force, of which the U.S. Department of Transportation is a member. The monarch butterfly is found throughout the lower 48 states, Hawaii, southern Canada, and northern South America. Because of its large bright orange and black-patterned wings and its migration path spanning much of the northwestern hemisphere, its decline has been more noticeable than most other pollinators. This butterfly has experienced a precipitous population decline. Thus, it is under review by the U.S. Fish and Wildlife Service for listing as a threatened species (a decision is anticipated by June 30, 2019). The reasons for its decline listed in scientific and popular science literature include: habitat and food source loss, invasive plant species that outcompete milkweed, pesticide use, and illegal logging in its very limited overwintering grounds. There is a need to study the relationship between roadside habitat and the various life stages of monarch butterflies as one of the proactive conservation strategies for the species. The objective of this research is to develop and validate a methodology for transportation practitioners to determine if roadway corridors are sources or sinks (beneficial or detrimental) to the monarch butterfly and how to maximize the beneficial aspects and minimize the detrimental impacts. The methodology should address a broad range of variables related to the project objective such as, but not limited to, the following: (1) Accounting for the differences and similarities between the eastern and western monarch butterfly populations, and migratory and non-migratory populations; (2) Analyzing mortality rates related to roadsides; (3) Considering traffic volume, speed, right-of- way width, and roadway width; (4) Assigning functional values for different roadside vegetation types; (5) Evaluating the effects of adjacent land use and habitat; (6) Considering roadway right-of-way maintenance practices (e.g., mowing, salt, burning, timing, pesticides); and (7) Considering environmental variables (e.g., climate, precipitation, elevation and aspect). While the methodology should be directly applicable to most situations, it should also outline decision-making processes and criteria that would assist transportation practitioners in identifying flexible solutions. Ultimately, the methodology should allow users to select and prioritize the most advantageous locations for butterfly habitat enhancement on a landscape scale (i.e., how large do habitat patches need to be and are there considerations of the amount of habitat adjacent to the roadways that would make selections of particular roadside locations more beneficial than others?).


  • English


  • Status: Active
  • Funding: $350000
  • Contract Numbers:

    Project 20-119

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Rogers, William

  • Performing Organizations:

    University of Minnesota

  • Principal Investigators:

    Oberhauser, Karen

  • Start Date: 20170313
  • Expected Completion Date: 20190313
  • Actual Completion Date: 0
  • Source Data: RiP Project 41493

Subject/Index Terms

Filing Info

  • Accession Number: 01628807
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-119
  • Files: TRB, RiP
  • Created Date: Mar 12 2017 1:00AM