CPC Plant Profile: Island Barberry
Search / Plant Profile / Berberis pinnata ssp. insularis
Plant Profile

Island Barberry (Berberis pinnata ssp. insularis)

In February the island barberry produces flowers with bright yellow petals. Photo Credit: Dieter Wilken
Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Berberidaceae
  • State: CA
  • Nature Serve ID: 157113
  • Date Inducted in National Collection: 01/17/2019

Although once known from three California Channel Islands, island barberry survives today at only a handful of known localities on Santa Cruz Island. (National Park Service 2002) Until 2017, it was known from only 5 individuals on Santa Cruz Island, until intense searches resulted in the discovery of 14 new clusters of plants located in a densely vegetated canyon. Intensive sheep and cattle grazing for over 150 years contributed to its loss on Santa Rosa Island. (Klinger et al. 2002) The last remaining plants on Anacapa Island died in the 1980s. (USFWS 2000) Island barberry is a shrub about 2-3 meters tall, and produces new shoots from short underground runners. Thus, mature plants often have multiple trunks, which form colonies up to 3 meters wide. The bright yellow flowers are produced in February, followed by grayish blue fruits in late May. (Breen 2017) Plants have been successfully cultivated at several botanic gardens in California, but wild plants produce little seed and propagation via cuttings can be challenging. Collectively, they show variation among leaf structure and color, suggesting that ex situ collections may be an important resource for recovery purposes.

Participating Institutions
CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.
Updates
  • 10/16/2020
  • Reproductive Research

Wilken (1996) has also studied the reproductive strategy of this species.

  • 10/16/2020
  • Propagation Research

Studies at the Santa Barbara Botanic Garden have focused on germination and cultivation requirements, which include moist cold stratification for 3 months and shaded conditions for container plants.

  • 10/16/2020
  • Genetic Research

Genetic studies conducted at Rancho Santa Ana Botanic Garden in 2016 found distinct differences among the five wild plants known at that time, but only one is represented in living collections.

  • 10/16/2020
  • Tissue Culture

Partners at the Huntington Library are actively pursuing tissue culture as a means for propagating this species, which is difficult to propagate by cuttings and produces little seed in the wild.

  • 10/16/2020
  • Propagation Research

The Santa Barbara Botanic Garden is actively investigating methods for vegetative propagation of this species to increase the probability of successful augmentation of wild populations.

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, Santa Barbara Botanic Garden holds 3 accessions of Berberis pinnata subsp. insularis in orthodox seed collection. There are as many as 110 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, Santa Barbara Botanic Garden has collected 3 seed accessions of Berberis pinnata subsp. insularis from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 3 maternal plants

Heather Schneider, PhD
  • 11/30/2017

In July 2017, intense searches resulted in the discovery of approximately 14 new clusters of island barberry growing in dense brush in a Santa Cruz Island Canyon. Upcoming genetic work will help determine the lineage of these plants and whether they are represented in ex situ collections.

Heather Schneider, PhD
  • 11/21/2017

The Santa Barbara Botanic Garden is actively investigating methods for vegetative propagation of this species to increase the probability of successful augmentation of wild populations. Partners at the Huntington Library are actively pursuing tissue culture as a means for propagating this species, which is difficult to propagate by cuttings and produces little seed in the wild.

Heather Schneider, PhD
  • 11/21/2017

Genetic studies conducted at Rancho Santa Ana Botanic Garden in 2016 found distinct differences among the five wild plants known at that time, but only one is represented in living collections. Ironically, a second island barberry plant common among botanic garden collections is not one of the 5 known wild genotypes. Upcoming genetics work will determine assess the plants located in 2017 and whether they may represent the common botanic garden genotype.

Nature Serve Biotics
  • 05/02/2017

Historically known from 3 of the Channel Islands off the coast of southern California. Apparently extirpated on Santa Rosa and West Anacapa islands, and now known to be extant at only 3 sites on Santa Cruz Island. The 3 Santa Cruz sites probably have fewer than 5 genetic individuals each. None show signs of successful sexual reproduction. Soil loss and other habitat alterations caused by feral pig rooting is a threat. Pigs and other introduced mammals have drastically altered the islands' ecosystems over the past 150 years. (USFWS 2013)

Dieter Wilken, Ph.D.
  • 01/01/2010

As listed in the recovery plan for thirteen plants from the northern channel islands (USFWS 2000): habitat alteration by feral pigs, including erosion; erosion associated with a road at one site; and reduced reproduction from low pollinator activity.

Dieter Wilken, Ph.D.
  • 01/01/2010

One extant locality has at least two plants separated by about 200 meters. Attempts to find additional plants have been unsuccessful, because of dense vegetation and inaccessibility. A second locality has a single, large cluster of multiple stems (Jeff Howart, pers. comm.). The remaining locality may have had as many as seven individuals in the 1980s (Wilken 1996), but recent observations indicate the presence of a single large cluster of multiple stems (Steve Junak, pers. comm.).

Dieter Wilken, Ph.D.
  • 01/01/2010

Studies at the Santa Barbara Botanic Garden have focused on germination and cultivation requirements, which include moist cold stratification for 3 months and shaded conditions for container plants. Wilken (1996) has also studied the reproductive strategy of this species.

Dieter Wilken, Ph.D.
  • 01/01/2010

Sites on Santa Cruz Island occur on lands are owned and managed by The Nature Conservancy. The latter, in cooperation with the National Park Service, is developing a plan for feral pig removal and reduction of exotic weeds. However, no short-term measures have been taken to protect vulnerable plants from erosion or pig rooting.

Dieter Wilken, Ph.D.
  • 01/01/2010

Genetic relationships among plants of ssp. insularis, and to mainland populations of ssp. pinnata. Surveys for undiscovered populations.

Dieter Wilken, Ph.D.
  • 01/01/2010

Development of a living collection representing all known genets.

MORE

Be the first to post an update!

Photos
Videos
Nomenclature
Taxon Berberis pinnata ssp. insularis
Authority Munz
Family Berberidaceae
CPC Number 2778
ITIS 18829
USDA MAPII
Common Names Island Barberry
Associated Scientific Names Mahonia pinnata ssp. insularis | Berberis pinnata ssp. insularis
Distribution Formerly known from Anacapa, Santa Cruz, and Santa Rosa islands in the Calfornia Channel Islands, island barberry is represented by very few individuals that remain on Santa Cruz Island today. (USFWS 2013)
State Rank
State State Rank
California S1
Habitat

This taxon grows in habitats with rocky soils of cool, moist, north-facing slopes and canyons in mixed chaparral and oak woodland (McEachern et al. 2010, Junak et al. 1995). Common associates on Santa Cruz Island include Quercus agrifolia, Comarostaphylis, Heteromeles, Pinus muricata, and Toxicodendron (Wilken pers. observations, Chaney 1994)

Ecological Relationships

Plants derived from seedlings are slow growing, averaging only about 50 cm per year. However, vegetative shoots from established rhizomes may grow as much as 1 meter per year. Plants are self-compatible, but flowers depend on insect visitation for maximum seed set (Wilken 1996). Natural pollination has not been studied, but honeybees are common visitors on plants at the Santa Barbara Botanic Garden. Fruits are dispersed by birds, including the endemic Santa Cruz Island blue jay (Wilken, pers. observations).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Mining bees Andrenidae Confirmed Pollinator Link
Bees Confirmed Pollinator Link
Bees Confirmed Pollinator Link
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

Donate to CPC to Save this Species

CPC secures rare plants for future generations by coordinating on-the-ground conservation and training the next generation of plant conservation professionals. Donate today to help save rare plants from extinction.

Donate Today