Presidio Manzanita (Arctostaphylos montana ssp. ravenii)
Presidio manzanita is a California endangered plant species, which means that killing or possessing plants from wild populations is prohibited by the California Endangered Species Act (CESA). The species is also listed as endangered under the federal Endangered Species Act. Presidio manzanita is an evergreen shrub that grows low to the ground, and produces white flowers that typically appear in February and March. There is only one wild presidio manzanita plant that is known to remain (pictured to the right). This plant is located on a serpentine outcrop of the San Francisco Presidio in a maritime chaparral-coastal prairie plant community. No natural germination of seed from this plant has been observed. Additional genetically-identical Presidio manzanita plants have been propagated from cuttings and established at other locations of the Presidio and in Botanical Gardens, and the UC Berkeley Botanical Garden population also contains seedling-grown plants.
Plant populations can normally recover from environmental events such as drought, storm damage and fires, and may also be able to recover from human-caused disturbances; however, very small populations can be especially vulnerable to these events. Because Presidio manzanita has been so severely reduced in numbers, it is especially vulnerable to extinction in the wild. In addition, much of the species’ genetic diversity has likely been lost, which may mean that any populations of the species that are established in the future will not be able to adapt to future changes in habitat, putting this species at further risk of extinction. Presidio manzanita may also be at risk of extinction from competition with other plant species, loss of insects necessary for a portion of its life cycle, loss of mycorrhizal fungi, disease or climate change.
Recommended actions for Presidio manzanita identified in the 2012 U.S. Fish and Wildlife Service 5-Year Review for Presidio manzanita include increasing the number of genetically-different individual plants using seed from the soil beneath the wild plant, investigating the factors that may contribute to a healthy pollinator community in the Presidio, and further investigating the best techniques for successful outplanting.
CDFW may issue permits for Presidio manzanita pursuant to CESA, and you can learn more about the California laws protecting Presidio manzanita and other California native plants. Presidio manzanita occurs in CDFW’s Bay Delta Region. More information is also available from the U.S. Fish and Wildlife Service’s Species Profile for Presidio Manzanita.
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