Sierra-San Joaquin Noxious Weed Alliance


Region covered : Fresno, Mariposa & Madera Counties

Chair: Joanna Clines, Sierra National Forest

General contact: Joanna Clines at (559) 877-2218 x3150 or

Mapping contact: Joanna Clines

Meetings: Three times a year at the US Forest Service,
Sierra National Forest, Bass Lake Ranger District, North Fork, CA

Formed: 1998


Outreach Summary:


  • Top 10 Noxious Weeds and Invasive of Mariposa, Madera, and Fresno brochure
  • Field Guide to Invasive Non-Native Weeds of Mariposa, Madera, and Fresno Counties


  • The WMA has attended from 5-10 local community events annually, using our table-top display and live plant material to educate the public about invasive weeds and encouraging participation in the 50:50 cost-share programs offered through each county for yellow starthistle control. Various members of the WMA give presentations to all manner of groups about the weed problem; examples include: realtors’ organizations, Rotary clubs, homeowners associations, garden clubs, utility company employees, and much more. .


  • The Met Cinema in Oakhurst shows a slide about yellow starthistle prior to movie showings, with information on how to participate in the cost-share program.


Project Highlights:

    Merced River Canyon east

  • Along the Merced River Canyon east of Yosemite National Park, 50 acres of weeds are being controlled. This includes
    yellow starthistle, Italian thistle, arundo, tocalote and spotted knapweed. Methods implemented are herbicide (glyphosate), hand-pulling and weed-whacking.This is an important “leading edge” site for yellow starthistle along the Merced Wild and Scenic River. The area is prized for its prime native plant and wildlife habitat, spectacular spring wildflowers, white-water rafting and other recreational opportunities, and because it is the western entrance to the world-famous Yosemite National Park.
    Project partners: Sierra National Forest; Mariposa County; Upper Merced Watershed Council; California Mule Deer Foundation, Merced Chapter; Bureau of Land Management, Yosemite National Park, California Department of Food and Agriculture.

   Yellow starthistle leading edge

  • Mariposa, Madera, and Fresno counties are working together to control yellow starthistle in a leading edge project. Approximately 600 acres treated for yellow starthistle annually. Methods used are surveying, mapping, education, hand-pulling, herbicide, mowing and monitoring. The entire central Sierra Nevada beyond our clearly identified leading edge line is free of YST, and our firm goal is to keep it that way and to reverse the spread by continuing to eradicate infestations at the leading edge.
    Project partners: All partners shown in our MOU have participated in some way in this.

   Early detection of A- and B-rated noxious weeds

  • Early detection and rapid response is being implemented to abate A- and B-rated noxious weeds in Mariposa, Madera, and Fresno counties. Species: Spotted knapweed: 20 infestations detected and eradicated over the past 8 years; Perennial pepperweed: 3 infestations detected and under eradication; Hoary cress: 1 infestation detected and under eradication, Lens-podded hoary cress: 1 infestation detected and under eradication. Populations of purple starthistle have been eradicated in Fresno County and rush skeletonweed is spreading in Fresno County due to inadequate funding but eradication efforts continue. Iberian starthistle is under eradication in Mariposa County. Methods used are Surveying, hand-pulling and bagging, and herbicide.
    Pristine Sierra Nevada plant communities, wildlife habitat, livestock forage, recreational value of the high sierra, watershed integrity. Project partners: All WMA partners.

Organizations on WMA’s MOU

  • California Department of Food and Agriculture
  • California Department of Parks and Recreations, San Joaquin Sector
  • California Department of Transportation, Districts 6 and 10
  • California Native Plant Society, Sequoia Chapter
  • Central Sierra Watershed Committee
  • Coarsegold Resource Conservation District
  • Chowchilla-Redtop Resource Conservation District
  • Fresno County Department of Food and Agriculture
  • Madera County Department of Food and Agriculture
  • Mariposa County Department of Agriculture
  • Mariposa County Resource Conservation District
  • Pacific Gas and Electric Company
  • Sierra Foothill Conservancy
  • Sierra Resource Conservation District
  • Southern California Edison Company, Shaver Lake Forestry Department
  • University of California Cooperative Extension, Mariposa County
  • USDA Forest Service, Sierra National Forest
  • USDI National Park Service, Yosemite National Park

Other regularly participating organizations

  • USDA Natural Resources Conservation Service
  • USDI Bureau of Land Management
  • San Joaquin River Parkway and Conservation Trust
  • Yosemite-Sequoia Resource Conservation and Development Council
  • Flying O Ranch property owners (Madera County)
  • Central Unified School District
  • North Fork Mono Rancheria