Invasive Plant Update


The Invasive Plant Management Plan Update will give Yosemite National Park resource managers greater flexibility in responding to present and future threats to park resources from non-native invasive species. No one method or herbicide is best for controlling all species in all situations, and new herbicides are continually being developed, tested, and approved for use. Adaptive management would allow the park to assess the safety and effectiveness of herbicides considered for protecting Yosemite’s biodiversity. It would provide a framework for decision making and prioritization strategies that based upon the time tested paradigms of Adaptive and Integrated Pest Management. As an example, two herbicides, glyphosate and aminopyralid are currently used in the park. Following the 2009 Big Meadow Fire in Yosemite, the Interagency Fire Management Team recommended applying a pre-emergent herbicide that to prevent cheatgrass from overtaking the meadow after the late-season fire. Since this specific chemical was not considered and evaluated in the 2008 IPMP, the park was unable to use this new tool. Successful aspects of the IPMP, such as annual work plans, prioritization, minimum tool analysis, and education, and outreach, would continue to be implemented.

Additional goals could include:

  • Refining monitoring protocols to assess the effectiveness of weed control actions and potential impacts of such actions to non-target species and water quality. These protocols could also allow managers to respond more effectively to the uncertainties such as large wildfires and climate change.
  • Identifying safe and effective methods for managing invasive wetland and riparian plant species.
  • Addressing language in the plan that precludes using all existing tools to manage new invasive species populations and also populations in wilderness areas of the park.
  • Assuring cultural resource protection under the National Historic Preservation Act, including traditional gathering areas, in consultation with American Indian Tribes

Last updated: March 1, 2015

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Yosemite National Park, CA 95389


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