Overview

Distribution

National Distribution

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

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Global Range: Linear occurrence, along Fish Canyon, Los Angeles County.

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This plant occurs only within Los Angeles County, California in portions of the San Gabriel Mountains. This rare taxon is further restricted in distribution to granitic slope from 350 to 600 meters in elevation.

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Ecology

Habitat

Comments: Chaparral; granitic.

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Population Biology

Number of Occurrences

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 1 - 5

Comments: 1 EO, found along Fish Canyon in the Angeles National Forest in Los Angeles County.

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Conservation

Conservation Status

National NatureServe Conservation Status

United States

Rounded National Status Rank: N1 - Critically Imperiled

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NatureServe Conservation Status

Rounded Global Status Rank: T1 - Critically Imperiled

Reasons: Endemic to California, Dudleya cymosa ssp. crebrifolia occurs only in Los Angeles County and is known only from the type locality along Fish Canyon. It is 90% located on federal (USFS) lands and 10% extirpated on private lands which are mined for decomposed granite. The majority of the population occurs on cliff faces along Fish Canyon and the population extends for about 1 mile up the canyon. Threats to the plants on USFS land are relatively unthreatened with some possible low threats from recreation activites, erosion, etc. The population size is somewhat unknown since older field survey forms stated there were "thousands" of plants and the newest form states they saw 40 plants. The author of this account (Bittman, 2010) does not believe there are only 40 plants right now nor that there were many thousands in decades past. I am guessing, from having been there, that there may be as many as 3000 or something less than that. Binocular surveys would help in this case. Regular (every 5 years) monitoring would be very helpful to track trends of this narrow endemic.

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Global Short Term Trend: Relatively stable (=10% change)

Comments: Although the most recent field survey form states that there were only 40 plants versus older data that stated there were "thousands" I have to wonder at the accuracy of either of these numbers. I (Bittman) have been to this site and there are many plants on the canyon walls both at human height at the trail and well above the trail in the rocks of the canyon above. A number in the low thousands may be the most accurate estimate.

Global Long Term Trend: Unknown

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Threats

Comments: The mouth of the canyon is privately owned and mined and is mostly destroyed (for mining of the granite). The canyon walls near the Angeles National Forest boundary have been removed and habitat is lost there. However, further into the canyon, the ownership is the Angeles National Forest and there are few threats. Some hiking occurs here and there could be some threat of collection, erosion or other recreational use. Threats are thought to be low at this time.

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Relevance to Humans and Ecosystems

Risks

Stewardship Overview: This is a case where there is not much for the USFS to do for this plant. It is de facto protected by its habitat preference which is steep cliff faces in a single canyon on the Angeles NF (Fish Canyon). The mouth of the canyon is heavily destructively mined and all plants or habitat is destroyed there. However, the bulk of the plants occur upstream on USFS lands. There could be some minor threats from recreational use and erosion. Also, we do not have a good population count. The main suggestion would be to monitor the plant every 5 years and include a fairly complete plant count, perhaps using binoculars to help see the plants well above line of sight on the canyon walls.

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