The following Participating Institutions are custodians for this species in the CPC National Collection:
Santa Barbara Botanic Garden
The conservation of Berberis pinnata ssp. insularis is fully sponsored.
Dieter Wilken, Ph.D. contributed to this Plant Profile.
Although once known from three California Channel Islands, island barberry survives today at only 3 known localities on Santa Cruz Island, perhaps represented by only 1-3 plants in each. Intensive sheep and cattle grazing for over 150 years contributed to its loss on Santa Rosa Island. The last remaining plants on Anacapa Island died in the 1980s.
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. Plants have been successfully cultivated at several botanic gardens in California. Collectively they show variation among leaf structure and color, suggesting that ex situ collections may be an important resource for recovery purposes.
Distribution & Occurrence
Rocky soils of cool, moist, north-facing slopes and canyons in mixed chaparral and oak woodland. Common associates on Santa Cruz Island include Quercus agrifolia, Comarostaphylis, Heteromeles, Pinus muricata, and Toxicodendron.
|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.).|
Conservation, Ecology & Research
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).
Habitat alteration by feral pigs, including erosion.
Erosion associated with a road at one site.
Reduced reproduction from low pollinator activity, pr
Wilken (1996) has also studied the reproductive strategy of this species.
Surveys for undiscovered populations.