CPC Plant Profile: Presidio Clarkia
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Plant Profile

Presidio Clarkia (Clarkia franciscana)

The lavender-pink petals and long narrow leaves of the Presidio clarkia. Photo Credit: Holly Forbes
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Onagraceae
  • State: CA
  • Nature Serve ID: 159779
  • Date Inducted in National Collection: 03/08/1989

Presidio clarkia is a slender annual herb, less than 0.4 m. tall with lavender-pink flowers that open from May to July. It is restricted to serpentine substrates in the San Francisco Bay area of California, where it is currently known from fewer than 5 sites in San Francisco and Alameda counties. Two sites within the San Francisco city limits are in the heavily used San Francisco Presidio (National Park Service) and are threatened by overuse by pedestrians and bicyclists, grass mowing before annual seed set, and the encroachment of non-native plants. The largest population, located 27 kilometers east of San Francisco in Alameda County, is in a regional park, but is similarly threatened by alien annual grasses and other non-native, invasive plants. Encroaching development potentially threatens a small population (NatureServe 2001).

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Updates
  • 09/04/2020
  • Orthodox Seed Banking

Additional seed collection for long-term storage is desirable.

  • 09/04/2020
  • Seed Collection

Additional seed collection for long-term storage is desirable.

  • 09/04/2020
  • Genetic Research

Published studies on the Presidio clarkia include the genetic variation between populations (Gottlieb and Edwards 1992) and its relationship with two other species of Clarkia (Gottlieb 1973)

Holly Forbes
  • 08/30/2017

Potential development Non-native species invasions Roadside maintenance Foot traffic Mowing before seed set Shade from native and introduced shrubs and trees

Holly Forbes
  • 08/30/2017

The National Park Service is planning experiments to determine the best habitat management techniques for the species, including: demography soil seed bank reproduction techniques for opening new habitat for seeding

Holly Forbes
  • 08/30/2017

Published studies on the Presidio clarkia include the genetic variation between populations (Gottlieb and Edwards 1992) and its relationship with two other species of Clarkia (Gottlieb 1973). Permanent vegetation transects were established in 1995 (USFWS 1998).

Nature Serve Biotics
  • 05/02/2017

Restricted to Serpentine substrates in the San Francisco Bay area of California. Currently known from fewer than 5 sites in San Francisco and Alameda counties. 2 sites within the San Francisco city limits are in a heavily used park and are threatened by overuse by pedestrians and bicyclists, grass mowing before annual seed set, and the encroachment of non-native plants. The largest population, located in Alameda County, is in a regional park, but is similarly threatened by alien annual grasses and other non-native, invasive plants. Encroaching development potentially threatens a small population.

Holly Forbes
  • 01/01/2010

Two extant populations are known from the San Francisco Presidio; one of these is thought to be introduced. While the number of plants fluctuates from year to year, the upper limit to the total numbers of plants reported in the Presidio is 8,000 in 1995. Three populations are known from the Oakland Hills in Alameda County, and are probably the remaining portions of one population that has been fragmented by roads and houses. The largest of these three populations had 4,000 to 5,000 plants in 1993, while the other two had 200 and 30 plants, respectively (USFWS 1998).

Holly Forbes
  • 01/01/2010

The natural population in the Presidio is protected from development but is threatened by non-native plants, trampling and unfavorable mowing times. The Alameda County populations are the subject of on-going effort by volunteers working in collaboration with staff of the East Bay Regional Park District (EBRPD) to protect it from non-native plant encroachment. EBRPD recently removed nonnative trees and other vegetation that threatens the population at Redwood Regional Park. Non-native trees and the duff layer have been removed from its habitat, which has also been fenced. A portion of the Oakland population is on property that is being redeveloped; the City's permit requires protection at the site and long-term management for the benefit of the species (CDFG 2002).

Holly Forbes
  • 01/01/2010

Additional seed collection for long-term storage is desirable.

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Photos
Nomenclature
Taxon Clarkia franciscana
Authority Lewis & Raven
Family Onagraceae
CPC Number 983
ITIS 27599
USDA CLFR3
Common Names Presidio clarkia
Associated Scientific Names Clarkia franciscana
Distribution Presidio clarkia occurs only on serpentine substrates in Alameda and San Francisco Counties, California. Three of the five populations are on public lands, but two, in Alameda County, are on private
State Rank
State State Rank
California S1
Habitat

This species is restricted to grassland communities with serpentine soils. (USFWS 1998)

Ecological Relationships

Presidio Clarkia is a predominantly self-pollinating species. Population sizes vary tremendously from year to year, even dropping to zero and then regenerating from seedbanks during more favorable conditions. While there is little genetic variability within populations, the Presidio and Oakland Hills populations are genetically distinct (Gottlieb and Edwards 1992).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Sweat bees Halictid sweat bees Floral Visitor Link
Other
Self Only Confirmed Pollinator Link
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

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