The following Participating Institutions are custodians for this species in the CPC National Collection:
Santa Barbara Botanic Garden
Rancho Santa Ana Botanic Garden
The conservation of Arabis hoffmannii is fully sponsored.
Dieter Wilken, Ph.D. contributed to this Plant Profile.
Less than 150 plants in 3 populations are known to exist. Two populations each have less than 5 reproductive plants annually. The remaining population may have as many as 30 reproductive individuals in any one year. Although reproductive plants produce many fruits and seeds, most of the seeds are dispersed to adjacent, unfavorable sites. The primary threats to survival and recovery are feral pig activity, subsequent erosion, and competition from alien grasses.
Plants are monocarpic, growing vegetatively for 3-5 years before flowering, fruiting and dying (Wilken 1996). Reproductive plants grow up to 70 cm tall, each with about 40 fruits that contain about 125 seeds. The minute seeds are slightly winged and dispersed by wind. Vegetative plants less than 3 years old have solitary leaf rosettes about 1-3 cm wide and less than 5 cm tall. During the summer months the uppermost rosette leaves curve upward and become dormant, surrounding the growing tip. Reproductive leaf rosettes vary from 10-15 cm wide, and bear single erect racemes with small white to lavender flowers.
Distribution & Occurrence
Sandy to rocky soils of open sites in coastal shrublands, often on ledges or cliff ledges. Associated species include Coreopsis gigantea, Hazardia detonsa, Eriogonum arborescens, and Adenostoma fasciculatum at one site. Populations are found near the coast, usually where summer fog dominates during the late afternoon or night.
|Only 3-4 populations are known; 2-3 on Santa Cruz Island and one on Santa Rosa Island. The largest population, with an annual average of 30 reproductive individuals, occurs on Santa Cruz Island. The remaining populations are composed of 0-5 reproductive individuals in any one year. A third locality on Santa Cruz Island has remained inaccessible and unmonitored for at least 5 years.|
Conservation, Ecology & Research
Feral pig rooting activities directly affecting the Hoffman's rock cress plants.
Soil erosion following feral pig activity indirectly affecting the
Genetic analyses of populations, including variation among annual cohorts.
Collection of seeds from the population on Santa Rosa Island.
Surveys for undiscovered populations and for sites suitable for reintroduction.