Sierra-San Joaquin Noxious Weed Alliance
WMAs are local stakeholder groups working on weed projects. Typically, they are organized by county, through county Agricultural Commissioners' offices. All interested land management entities, public and private, are invited to participate. Official WMA partners sign a Memorandum of Understanding indicating their commitment to working on invasive plant problems to the extent resources allow. Each WMA develops a strategic plan that identifies their top priorities for local management. Together these partners plan and implement projects on-the-ground, and collaborate on mapping and public education. In the year 2000, there were fewer than 20 groups statewide—today there are 48 covering all counties.

Meetings: Three times a year at the US Forest Service,  Sierra National Forest, Bass Lake Ranger District, North Fork, CA
Formed: 1998

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. 

Contact Sierra-San Joaquin Noxious Weed Alliance

Joanna Clines
57003 Road 225
North Fork, California  93643
Phone: (559) 877-2218 x3150


Service Area

Services provided in:
  • Fresno County, California
  • Madera County, California
  • Mariposa County, California

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