Conejo Dudleya

Dudleya abramsii ssp. parva

Description

Dudleya abramsii ssp. parva, Conejo dudleya, forms a rosette of oblanceolate leaves that are 0.6-1.6 in (1.5-4 cm) long and 1.2-2.4 in (3-6 cm) wide; unlike most taxa in the subsection Dudleya, these leaves wither by early summer. The inflorescence is 2-7.1 in (5-18 cm) long, tipped with pale yellow flowers that are often flecked with red on the keel. The roots are constricted at irregular intervals. Dudleya abramsii ssp. parva is distinguished from other local Dudleya taxa by its flower color, root constrictions, and leaves that wither early.

Joseph Rose and Anstruther Davidson first described Dudleya abramsii ssp. parva (Conejo dudleya) as D. parva in 1923 from a cultivated collection made a year earlier by Mrs. J. H. Bullard in the Conejo Grade in Ventura County. No further mention was made of the plant in other regional floras for several decades, although Munz listed D. parva as a synonym of Echeveria lanceolata in 1935. In 1960, Reid Moran recognized D. parva in his treatment of the genus, as did Munz fourteen years later in his Flora of Southern California. Jim Bartel published the combination D. abramsii ssp. parva in 1991, basing his description on similar floral features between D. parva and D. abramsii.

Habitat

Conejo dudleya occurs exclusively at the base of scattered rock outcrops and soils derived from the Miocene Conejo volcanics at the western end of the Simi Hills and the Santa Monica Mountains. This plant commonly occurs in a cactus-dominated coastal sage scrub, which provides nesting habitat for the rare Bell's sage sparrow (Amphispiza belli belli ) and rufous-crowned sparrow (Amophila ruficeps ).

Distribution

Conejo dudleya is known only from the western terminus of the Simi Hills west along the Montclef Ridge to the Conejo Grade, a distance of approximately 10 mi (16 km). There are only 11 reported populations, with numbers of individuals varying from a few thousand at one population to as few as 25. The majority of the populations number in the hundreds of individuals. A portion of the plant's habitat is on lands designated as "open space"; the remaining habitat is privately owned.

Threats

Threats to Conejo dudleya include the recreational activities of hiking and equestrian use, fire management and suppression activities, urban development, and collection. Portions of populations of this taxon have been extirpated by development in the cities of Agoura Hills, Thousand Oaks, and Westlake Village. The majority of their distribution is on private lands located in a region with increasing development pressures. Conejo dudleya is also affected by trampling and off-road vehicle activities on public and private lands.

Conservation and Recovery

Some habitat of the Conejo dudleya occurs on land owned by the Conejo Open Space Conservation Agency. This habitat should be strictly protected from disturbances associated with outdoor recreation, and an appropriate fire regime should be prescribed and implemented. Most of the known habitat of the threatened Conejo dudleya is on privately owned land, and is at risk from destruction or degradation by residential development and other land-use practices. The largest critical habitats should be protected by acquisition and designation of ecological reserves, or by negotiating conservation easements with the landowners. The rare Conejo dudleya should be protected from any collection for horticultural or other uses. Its populations should be monitored, and research undertaken into its biology and habitat needs, with a view to developing appropriate management practices, including prescribed burning.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

U. S. Fish and Wildlife Service
Ventura Field Office
2493 Portola Road, Suite B
Ventura, California 93003-7726
Telephone: (805) 644-1766
Fax: (805) 644-3458

Reference

U. S. Fish and Wildlife Service. 29 January 1997. "Endangered and Threatened Wildlife and Plants: Determination of Endangered Status for Two Plants and Threatened Status for Four Plants From Southern California." Federal Register 62 (19).