Endangered Species in Santa Cruz County - Species Account

Santa Cruz Wallflower
(Erysimum teretifolium)

This information was taken from the following publication, which is available for reference use at the Central Branch Library:

Recovery Priority 9 —

Indicates a species having a moderate degree of threat and a high recovery potential.

Description and Taxonomy

Erysimum teretifolium [Santa Cruz Wallflower, also called the Ben Lomond Wallflower] was first collected at Glenwood, Santa Cruz County by Horace Davis in 1914. This plant was described by Alice Eastwood in 1938 as Erysimum filifolium, not realizing that this combination had already been applied to another plant (Eastwood 1938). Therefore, it was renamed Erysimum teretifolium the following year (Eastwood 1939).

Santa Cruz Wallflower is a short-lived perennial plant, or occasionally an annual, of the mustard family (Brassicaceae). Seedlings form a basal rosette of leaves which then wither as the main stem develops a raceme (flowers clustered in a terminal spike). The flowers are a deep yellow with petals 1.3-2.5 centimeters (0.5-1.0 inch) long. The fruit, a slender capsule, reaches 10 centimeters (4.0 inches) in length and is covered with three-parted hairs. Characteristics that separate this plant from other wallflowers include simple, narrowly linear leaves that have small marginal teeth and a purplish cast.

Life History

First year and, frequently, second-year plants consist of a basal rosette. In subsequent years, the basal rosette withers as the main flowering stem develops. In Erysimum species, flowering may be postponed due to unproductive habitat; therefore, some adults may be older than two years old. Successful reproduction most likely depends on habitat characteristics and climatic conditions (Berg 1986).

Brunette (1997) observed population structure and sampled seedbanks for the Santa Cruz Wallflower. He found that populations on South Ridge (Quail Hollow Quarry) exhibited a healthy population structure consisting of 63 percent seedlings, 21 percent subadults, 7 percent adults and 9 percent reproductive individuals; seedbanks ranged from 38 to 731 seeds per square meter. In contrast, the population at Bonny Doon Ecological Reserve supported 0 percent seedlings, 29 percent subadults, 57 percent adults, 14 percent reproductive individuals, and no seedbank.

Habitat Description

The Santa Cruz Wallflower is endemic to pockets of sandstone soils in the Santa Cruz Mountains. It is found in open areas within northern maritime chaparral and within the scattered ponderosa pines in the sand parklands. The best populations are found on ridgelines where underlying fossilized sand dollar beds inhibit the growth of all but herbaceous perennials and annuals.

Range and Distribution

Seventeen populations occur within the area generally bounded by the communities of Ben Lomond, Glenwood, Scotts Valley, and Felton, with one outlying population occurring in the Bonny Doon area, five miles west of Felton (Greening Associates 1996). One population occurs at Quail Hollow Ranch County Park, which is jointly owned by the County of Santa Cruz and the California Department of Fish and Game. The population near Bonny Doon is on the Bonny Doon Ecological Preserve owned by California Department of Fish and Game. The ownership of two recently reported populations is unconfirmed. One population located near Olympia Quarry (operated by RMC Lonestar) may be on California Department of Fish and Game property. The other population, on a roadcut along Highway 17 near Scotts Valley, is most likely within a California Department of Transportation (Caltrans) right-of-way. All other populations are on privately owned lands.

Population Status and Current Threats

Historical and continuing threats to the Santa Cruz Wallflower include the direct removal of habitat by sand quarrying and residential development. Alteration of habitat may also be occurring in the form of increased canopy density within the Ben Lomond sandhills as a result of fire suppression.

Only a few of the Santa Cruz Wallflower populations have been monitored sufficiently to provide trend information. The largest population is located south of Quail Hollow Road and comprises approximately 6,000 plants, about 75 percent of all individuals. This population has already been reduced in size by sand quarrying. The next largest population comprises about 700 plants and is near Ben Lomond in a residential-zoned area that is fragmented by private homes. Three populations support 200-400 individuals: Olympia Quarry, Quail Hollow Ranch County Park, and Scotts Valley. Eleven populations comprise fewer than 200 individuals each, and one population had no individuals the last time it was checked in 1986.

The population at Bonny Doon Ecological Reserve has fluctuated in size over the last 16 years. In 1982, there were "fewer than 1000" plants, and in 1986 there were "about 25." The population was "thriving" in 1994, but in 1997 there were only 28 individuals remaining (CNDDB 1997, Brunette 1997, Hames et al. 1993).

Conservation Efforts

The Santa Cruz Wallflower is afforded protection by the State of California; in 1981, Erysimum teretifolium was State-listed as endangered (Skinner and Pavlik 1994). Three populations of Santa Cruz Wallflower occur on sites that are afforded some protection. One population is on the recently acquired Quail Hollow Ranch County Park site; however, development of recreational facilities is being proposed for a portion of the ranch (County of Santa Cruz 1990). The other population occurs within the Bonny Doon Ecological Reserve; a draft management plan has recently been released for public review. A third site, at North Ridge, is protected through the 1997 Habitat Conservation Plan with Graniterock for Quail Hollow Quarry's "current mining area."

Needed Recovery Actions

Specific recovery actions for Santa Cruz Wallflower include:

  • Habitat Conservation Plan with the County of Santa Cruz that minimizes disturbance from sand mining and residential development,
  • Development and implementation of management plans for State-owned units (Quail Hollow Ranch County Park and Bonny Doon Ecological Reserve),
  • Conduct research focusing on causes of reproductive failure and how to increase reproductive success, and
  • Manage for reduction of succession of woody species into occupied habitat.