Transportation Funding Invasive Species Management

A Position Statement of the North American Invasive Species Management Association

Transportation Funding and Invasive Species Management

A Position Statement of the North American Invasive Species Management Association

Released: May 20, 2020


Transportation infrastructure and corridors provide numerous opportunities for the movement of invasive plants. Road maintenance and construction equipment can expose right-of-ways to aggressive expansion of existing infestations or introduce new invasive species into new ecosystems. Reclamation of right-of-ways can also introduce invasive species through contaminated seed or mulch. Studies have found that passenger vehicles can carry anywhere from three to 135 seeds per vehicle and vehicles can spread over 500 different plant species. As far back as 1896, western states recognized the threat that railroad rights-of-ways posed by passing legislation requiring the railroad companies to mitigate weeds along the rail lines.

In 2006, the National Highway Research Program published the NDHRP Synthesis 363 – control of Invasive Species – A Synthesis of Highway Practice. The publication noted in summary, “Inadequate funding is the primary obstacle faced by state DOTs and others trying to control invasive species.” Additionally, the report notes that mowing alone as a treatment mechanism, “…frequently results in resprouting and cloning and is not an effective control methodology.”

In many localities the weeds growing in highways are destroyed by the owners of abutting property, a practice that is heartily commended. The responsibility of the joint ownership of highways and the danger to adjoining property from roadside weeds, however, are not always sufficiently appreciated, and it is therefore deemed best to delegate this work to some officer who shall be responsible for its proper execution throughout a  district. Next to the railroad yards and the undeveloped lands  in cities and villages, the roadsides are the most important avenues for the introduction of new weeds and for the propagation of old ones. They should, therefore, be watched with special care.


The North American Invasive Species Management Association supports the creation of a grant program under Section 1528 (Invasive plant elimination program) of Senate File 2302 – America’s Transportation Infrastructure Act of 2019. NAISMA believes Section 1528 will assist states in managing and mitigating the impact invasive plants have along the nation’s transportation corridors. NAISMA believes a grant program requiring a match from participating states will ensure individual states’ departments of transportation are actively involved in the management programs. In addition, we encourage coordination between relevant invasive species management authorities and local governments and organizations.

NAISMA is concerned that Section 1528 does give priority to management programs that utilize native plants and wildflowers. We suggest that grants made under this program require measurements to demonstrate the reductions in invasive plants regardless of the type of management.  The Association recommends striving for a balance between the support of  pollinator corridors and mitigating the impacts of invasive species in the surrounding ecological system. 


  1. Weed Seed Dispersal by Vehicles. Montana State University Extension MontGuide.

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