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Chorro Creek Bog Thistle

(Cirsium fontinale var. obispoense)

Chorro Creek bog thistle is a California endangered plant species, which means that killing or possessing the plant is prohibited by the California Endangered Species Act (CESA). Chorro Creek bog thistle only occurs naturally in San Luis Obispo County and is restricted to open seep areas in serpentine soil outcrops. Chorro Creek bog thistle is known from only 13 California Natural Diversity Database occurrences, and due to its very specific habitat requirements it is unlikely that Chorro Creek bog thistle was ever very abundant. Chorro Creek bog thistle is also listed as endangered under the federal Endangered Species Act.

Populations of Chorro Creek bog thistle are threatened by impacts from cattle such as trampling, changes in the hydrology or water quality of occupied habitat including loss of natural water supply, competition with non-native plant species, and possibly due to the future effects of climate change. Protective fencing has been installed around some populations of Chorro Creek bog thistle to protect them from trampling. Despite some protections, Chorro Creek bog thistle continues to be threatened by the factors described above, and due to the vulnerability of small and localized plant populations to extirpation.

Several actions should be accomplished to conserve Chorro Creek bog thistle. These include working with local organizations and private landowners to survey for and conserve additional populations of Chorro Creek bog thistle; monitoring the life history stages of known populations; conducting hydrological studies of the water sources necessary for the populations; ensuring water sources are maintained; and expanding existing fencing enclosures for protection and to possibly expand populations. This Chorro Creek Bog Thistle Recovery Project report was funded by the Emergency Drought Relief Project and submitted to CDFW.

CDFW may issue permits for Chorro Creek bog thistle pursuant to CESA, and you can learn more about the California laws protecting Chorro Creek bog thistle and other California native plants. Populations of Chorro Creek bog thistle occur in CDFW's Central Region. More information is also available from the United States Fish and Wildlife Service Species Profile for Chorro Creek bog thistle.

Updated 3/19/2013

For more information on any of the topics above, please contact the Native Plant Program at

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Habitat Conservation Planning Branch
1700 9th Street, 2nd Floor, Sacramento, CA 95811
Mailing: P.O. Box 944209, Sacramento, CA 94244-2090
(916) 653-4875

Cirsium fontinale var. obispoense, CDFW photo by Jeb Bjerke
Cirsium fontinale var. obispoense, CDFW photo by Jeb Bjerke

Cirsium fontinale var. obispoense CDFW illustration by Mary Ann Showers, click for full-sized image
Cirsium fontinale var. obispoense CDFW illustration by Mary Ann Showers, click for full-sized image