CPC Plant Profile: Otay Manzanita
Search / Plant Profile / Arctostaphylos otayensis
Plant Profile

Otay Manzanita (Arctostaphylos otayensis)

Photo Credit: Stacy Anderson
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Ericaceae
  • State: CA
  • Nature Serve ID: 138976
  • Date Inducted in National Collection: 09/23/2021

Arctostaphylos otayensis is a beautiful, rare, native shrub that grows almost exclusively on Otay Mountain. Smaller populations occur on neighboring San Miguel Mountain and it is believed that the species occurs on the small portion of the San Ysidro Mountains that extends into Baja California, Mexico, but there is not definitive data available. It's leaves are striking - light pink when new, and gray- green when mature. The shrub blooms from January through April, with tight clusters of white or lightly pink flowers. It grows on stony slopes and volcanic rock outcrops, at elevations from 1000-4000 feet. Unlike many other Arctostaphylos species, it does not have an underground burl and cannot resprout after intense fire.

Participating Institutions
Updates
  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, San Diego Zoo Global holds 2 accessions of Arctostaphylos otayensis in orthodox seed collection. There are as many as 8843 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, San Diego Zoo Global has collected 2 seed accessions of Arctostaphylos otayensis from 2 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 105 maternal plants

Joe Davitt
  • 08/18/2017

Curbing the threat of fire through the removal of invasive plants and the limiting of illegal activities is needed. More ex-situ (seed bank) collections are needed to insure that the breadth of the genetic diversity is conserved. Arctostaphylos species are known to have low germination rates and research into the germination cues for the species would be helpful in guiding any reintroduction actions if needed.

Joe Davitt
  • 08/18/2017

I would classify the status of the species as stable. The population historically declined as a result of some development of roads, utilites, etc. but the threat to the species now is the fact that the range is very small. It would not be surprising for a single fire to cover most of the species' range. This would not result in the immediate extinction of the species but it would be very imperiled while it recovered after such a fire.

Joe Davitt
  • 08/18/2017

Because this species does not have a burl, it is very threatened by an increase in fire frequency. Old plants can not resprout from roots or burl after intense fires. While this makes room for a new generation, the new trees that germinate after a fire will take several years before they are reproducing. If another fire passes through before populations are reproducing it is possible that the population will be unable to survive. An increased fire-frequency is generally a result of invasive non-natives, especially grasses, that quickly increase the dry biomass in an area and can quickly start a fire. A large portion of the populations of this species occur on public lands (BLM). Increased human activity, illegal fires, cigarettes, firearms, off road vehicles are all potential threats to the species.

Joe Davitt
  • 08/03/2017

In 2016, San Diego Zoo Global made two seed collections from different populations on Otay Mountain.

Nature Serve Biotics
  • 05/02/2017

Endemic to a small area in San Diego County, California, there are 18 known occurrences of Arctostaphylos otayensis but many are historic. Threatened by development.

MORE

Be the first to post an update!

Photos
Nomenclature
Taxon Arctostaphylos otayensis
Authority Wies. & Schreib.
Family Ericaceae
CPC Number 233
ITIS 23507
USDA AROT
Common Names Otay manzanita
Associated Scientific Names Arctostaphylos otayensis
Distribution Limited mainly to Otay Mountain, with populations on San Miguel Mountain and possibly on the San Ysidro Mountains that extend into Baja California, Mexico.
State Rank
State State Rank
California S2
Habitat

Chaparral or Cismontane woodland habitats in metavolcanic soils. Occurs on rocky slopes or outcrops. The San Ysidro Mountains are an ancient volcano system and seem to support a high number of endemic taxa. It is possible that the metavolcanic rock and soils are a limiting factor in the species dispersal.

Ecological Relationships

The plant community on Otay Mountain is very unique and often dominated by rare or unusual species. Arctostaphylos otayensis, Herserocyparis forbesii (Tecate cypress), Chamaebatia australis (southern mountain misery), Pickeringia montana, Lepechinia ganderi, and Ceanothus otayensis (Otay Mountain lilac) are all very common in places, though rare throughout the rest of the County. Also of note, Arctostaphylos glandulosa ssp. glandulosa is present in dense stands throughout the habitat. This species is distinguished by a large burl at its base, and slight differences in leaf and flower morphology, but there is some concern that the two species might hybridize. In places where the two species coexist, there appear to be some intermediate individuals, but genetic work has not been completed.

Pollinators
Common Name Name in Text Association Type Source InteractionID

Donate to CPC to Save this Species

Fall fundraising drive has begun! We're looking for 2,500 people to protect our planet. With you by our side, we will build a future where people live in harmony with nature. Come help and become a CPC donor today.

Donate Today