CPC Plant Profile: Bakersfield Beavertail Cactus
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Plant Profile

Bakersfield Beavertail Cactus (Opuntia basilaris var. treleasei)

Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Cactaceae
  • State: AZ, CA, UT
  • Nature Serve ID: 156336
  • Date Inducted in National Collection: 09/18/2021

Very little is known about this variety of prickly pear cactus. About a third of the historic occurrences have been extirpated and the remaining populations are highly fragmented. This is due to habitat loss caused by agricultural development in the region in the early 1900's. Continued development along with several industrial and recreational activities still threaten the remaining populations. This variety grows in dense patches with many of its leaves overlapping with neighbors, making accurate individual counts difficult. This plant is measured as collections of pads that all appear to root at the same location or clusters to deal with this difficulty. When this cactus flowers in May, the patches become beautiful fields of large pink blossoms. (Brown and Cypher 1997)

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

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Opuntia basilaris var. treleasei in orthodox seed collection. There are as many as 412 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, California Botanic Garden has collected 1 seed accessions of Opuntia basilaris var. treleasei from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 23 maternal plants

Nature Serve Biotics
  • 05/02/2017

Historically, this taxon occurred in populations that were more or less continuous east of Bakersfield, California. It is now restricted to a limited area of central Kern County near the Southern San Joaquin Valley. About one-third of the historical occurrences have been extirpated due to the conversion of habitat into agriculture and urban development. The remaining populations are small and highly fragmented, concentrated into about 11 areas. Only four core areas contain populations of greater than 1,000 clumps. Remaining populations are threatened by loss of habitat from agricultural, urbanizing, mining and energy developments, off-road vehicle traffic, trash dumping, grazing, and competition with non-native invasive species.

  • 01/01/2010

Habitat loss due to development Petroleum production Sand and gravel mining Off-road vehicle (ORVs) Introduced grasses Air pollution Low genetic diversity (Brown and Cypher 1997) Overgrazing by sheep and cattle (HCPB 2002)

  • 01/01/2010

There are eleven sites supporting less than 20,000 clusters and only four sites contain populations of more than 1,000 clusters (Brown and Cypher 1997; USFWS 1998)

  • 01/01/2010

None known.

  • 01/01/2010

In 1997, three areas of Bakersfield cactus habitat were acquired as mitigation and are currently being managed to protect this rare variety. (CDFG 2002) In 1998, a regional recovery plan was drafted and included protection of this cactus. (USFWS 1998)

  • 01/01/2010

Basic natural history and reproductive biology Pollinator identification

  • 01/01/2010

Maintain genetically representative seed bank.

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Photos
Nomenclature
Taxon Opuntia basilaris var. treleasei
Authority (Coult.) Coult. ex Toumey
Family Cactaceae
CPC Number 3018
ITIS 195263
USDA OPBAT
Common Names Bakersfield beavertai cactus | Bakersfield cactus | Kern beavertail cactus | Trelease's beavertail prickleypear
Associated Scientific Names Opuntia basilaris var. treleasei | Opuntia treleasei
Distribution central Kern County, California in the vicinity of Bakersfield (Brown and Cypher 1997; USFWS 1998)
State Rank
State State Rank
Arizona SR
California S1
Utah S1
Habitat

Sandy soils in flood plains, ridges, bluffs, and rolling hills in the Pacific grassland and Mojavean Desert between 120 and 300 meters (Brown and Cypher 1997; USFWS 1998)

Ecological Relationships

Other Opuntia species require cross-pollination for successful seed-set, and are often pollinated by bees, but this information is not known for this particular species and variety. Vegetative reproduction is common in this and other Opuntia taxa, as fallen pads root if sufficient water is available. This particular prickly pear, however, will not survive prolonged inundation. Seed production in this taxon is infrequent. When seeds are produced, they likely require warm, wet conditions to germinate--two requirements that are seldom met at the same time in the habitat where the Bakersfield cactus is found.Source: Brown and Cypher 1997; USFWS 1998

Pollinators
Common Name Name in Text Association Type Source InteractionID

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