Willowy Monardella

Monardella linoides ssp. viminea

Description

Willowy monardella, Monardella linoides ssp. viminea, is a perennial herb in the mint family (Lamiaceae) with a woody base and aromatic foliage. The leaves of this species are linear to lance-shaped. Greenish-white, often rose-tipped bracts are below dense terminal heads of pale white to rose-colored flowers. This species can be distinguished from other members of the genus by its waxy green, hairy stems and its conspicuously gland-dotted bracts.

Habitat

Willowy monardella occurs in coastal sage scrub, grasslands on clay soils, or in a mosaic of sage scrub, chaparral, and riparian scrub habitats. It often grows in sandy washes and floodplains and is frequently associated with California buckwheat, sycamore, coast live oak, California sagebrush, and coyotebush.

Distribution

Populations of willowy monardella, which are concentrated in the Miramar area of San Diego County, extend south into Baja California, Mexico. This species was previously known from 27 occurrences in the United States. Approximately 6,000 individuals from 20 occurrences are thought to currently exist in the U.S. All populations, with the exception of two populations of approximately 200 individuals each at Cedar Canyon and Marron Valley occur between Penasquitos Canyon and Mission Gorge in San Diego County. Fifteen populations have fewer than 100 plants, and six of these populations contain fewer than 15 individuals. Most populations occur on federal land at Marine Corps Air Station, Miramar, including one of the largest populations. About 1,700 individuals were reported at that locale in 1994. One population occurs near Arroyo Jatay in northern Baja California, Mexico.

Threats

Habitat destruction or modification adversely affects species native to this area by reducing population densities and contributing to habitat fragmentation. Rapid urbanization and agricultural conversion in Orange and San Diego Counties has already eliminated or reduced populations of this species. The trend of habitat loss and fragmentation is expected to continue as the population of southern California expands. This species is also adversely affected by the invasion of non-native plants, off-road vehicle use, increased erosion, grazing, and trampling by humans

Willowy monardella was previously known from 27 occurrences in the United States, seven of which have been destroyed by transportation projects and industrial development. Of the five remaining occurrences with at least 100 individuals, none are currently protected. The remaining populations are threatened by urban development, sand and gravel mining, off-road vehicle activity, trampling, trash dumping, and erosion. One of the largest populations (2,000 to 3,000 individuals) is located in Sycamore Canyon City Park, which is partially on private property, partially on federal land managed by the U.S. Navy, and partially on city-owned property. This population has been damaged by off-road vehicles and fire, factors that also threaten the other remaining populations of this species. Two populations on Marine Corps Air Station, Miramar land have been partially destroyed by road construction. The other two large populations are on private property. One of these (approximately 340 individuals) is threatened by sand and gravel mining. The other population, with approximately 200 individuals, is on property proposed for development. Habitat for this species in Los Penasquitos City Regional Park is degraded by stream erosion, trash dumping, and the invasion of non-native species. Another population in San Clemente Park, owned by the City of San Diego, was reported to have approximately 60 plants in the early 1980s, but contained fewer than 35 plants in 1987.

Conservation and Recovery

In 1991, the State of California established the Natural Communities Conservation Planning program to address conservation needs of natural ecosystems throughout the state. The focus of the current planning program is the coastal sage scrub community in southern California, although other vegetation communities are being addressed in an ecosystem approach. Willowy monardella is currently covered under the Multiple Species Conservation Program and the Central/Coastal Subregional Natural Communities Conservation Planning/ Habitat Conservation Plan (Central/Coastal Natural Communities Conservation Planning) of Orange County, California, and is being considered for inclusion as a covered species under the Multiple Habitat Conservation Plan.

Contact

U.S. Fish and Wildlife Service
Office of the Regional Director
Eastside Federal Complex
911 N.E. 11th Avenue
Portland, Oregon 97232-4181
Telephone: (503) 231-6118
Fax: (503) 231-2122

Reference

U.S. Fish and Wildlife Service. 13 October 1998. "Determination of Endangered or Threatened Status for Four Plants From Southwestern California and Baja California, Mexico." 63 (197): 54937-54956.