• View of Half Dome and Washington Column in Yosemite Valley


    National Park California

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  • Tioga Road is Closed

    The Tioga Road (Highway 120 through the park) is closed due to snow; there is no estimated opening date, although it usually opens sometime in May. More »

  • Rain and snow is forecast Friday and Saturday

    The Glacier Point Road is closed and will be reevaluated on Sunday. Tire chains may be required; bring and be prepared to use them if visiting this weekend. Check current road conditions by calling 209/372-0200 (then dial 1 then 1).

Invasive Species

Plant with large yellow flower and huge thorns

Yellow star-thistle, an invasive plant, displaces native vegetation in Yosemite National Park.

Invasive species have a negative impact on natural resources nationwide, including in Yosemite National Park. Of concern:

Non-native animal species, like the New Zealand mud snail, concern park scientists because this species can completely cover a river streambed, thereby altering the ecosystem. Also, forest pests could threaten park resources and forest health by burrowing into Yosemite's tree bark. Park managers must work to prevent a pest outbreak from occurring.

Plant species, like Himalayan blackberry, can form impenetrable thickets that replace native vegetation. Yellow starthistle, which is a focus to remove in the park's lower elevations, also displaces native vegetation. Park botanists work to detect and prevent invasive plants, also referred to as noxious weeds, that cause ecological or economic damage. A freshwater algae, called Didymo, could threaten Yosemite's rivers and streams by forming massive blooms that carpet stream beds. [142 kb PDF]

Learn more about invasive plants through the park's invasive plant management plan, common techniques for invasive plant control, and the top 10 worst plant invaders in Yosemite.

Help the National Park Service by being aware of invasive plants and animals and by avoiding transporting unwanted visitors. It is much easier to prevent the spread of invasive species than to try to eradicate them once they are introduced.

Did You Know?

Yosemite Museum

When it opened to the public on May 29, 1926, the Yosemite Museum became the first museum building in the national park system, and its educational objectives served as a model for parks nationwide. It still functions much as it was originally intended, and currently exhibits items which mainly reflect the Native occupation of Yosemite Valley and its surroundings. When in the park, you can visit with one of three cultural demonstrators who primarily staff the Museum.