Encinitas Baccharis

views updated

Encinitas Baccharis

Baccharis vanessae

Status Threatened
Listed October 7, 1996
Family Compositae (Asteraceae)
Description A broom-like shrub with filiform leaves and delicate phyllaries that are reflexed at maturity.
Habitat Southern maritime chaparral.
Threats Habitat destruction by urbanization, and degradation caused by fire suppression and fuel modification, and invasion by non-native plants.
Range California

Description

Baccharis vanessae (Encinitas baccharis) was discovered in October 1976 in southern maritime chaparral on Eocene sandstones along the north side of Encinitas Boulevard in Encinitas, California. This member of the sunflower or aster family (Compositae or Asteraceae) is a dioecious broom-like shrub that reaches 1.6-4.3 ft (0.5-1.3 m) in height.

B. vanessae is distinguished from other members of the genus by its filiform leaves and delicate phyllaries that are reflexed at maturity.

Habitat

Encinitas baccharis occurs in southern maritime chaparral in central San Diego County in the vicinity of Encinitas and extends inland 20 mi (32 km) to Mount Woodson and Poway, where it is associated with dense southern mixed chaparral. One population of this plant occurs in the Santa Margarita Mountains of northern San Diego County. This plant is known to occur at 2,890 ft (880 m) in elevation on Mount Woodson.

Distribution

The historical distribution of Encinitas baccharis included 19 natural populations scattered from Encinitas east through the Del Dios highlands and Lake Hodges area to Mount Woodson and south to Poway and Carmel Mountain in San Diego County. Fourteen of these populations are still extant and together contain approximately 2,000 individuals. No population is known to have over 300 individuals, while five of them have less than six individuals. One individual has been discovered on the western slopes of Carmel Mountain. An additional disjunct individual was discovered on the western slopes of Carmel Mountain in 1993. This location harbors the southernmost known population. A single transplanted population of 34 individuals was established in San Dieguito Park, but this population has not persisted. The majority of the remaining populations are on private lands.

Threats

A single population of Encinitas baccharis is known from the Cleveland National Forest in the Santa Margarita Mountains. While this population is partly protected because of its isolation, it represents less than 10% of the known total numbers of this species. Many populations, those in close proximity to residential development, are threatened by the edge effects of fuel modification activities, fire suppression, the invasion of exotic plant species, and increased human activities associated with nearby urbanization. Unidentified pollinators or seed-dispersal agents for this species may also be damaged by nearby development.

Seven of the 14 remaining Encinitas baccharis populations are threatened by development projects. Five populations are in the Del Dios Highlands within the Rancho Cielo project area. Three of these are threatened by urban development and a golf course. Some of these plants may have already been eliminated by the combined actions of a serious fire in September 1990 that burned through 3,000 acres of Del Dios highland habitat, vegetation clearing in 1991 and 1992, and the application of herbicides in 1993. Two other populations near Lake Hodges have been identified as threatened by projected developments and inundation from a proposed water storage facility. This plant also occurs within Oak Crest Park in Encinitas. While this park is under public ownership and management, the Encinitas baccharis population there is threatened by the construction of recreational facilities that will reduce the extent of southern maritime chaparral within the park by approximately one-third. The development will be increase the risk from invasive alien plants and pedestrian trampling. Several important populations of this listed plant are threatened by current project proposals that will reduce the effectiveness of the Multiple Habitat Conservation Plan, when developed, to adequately stabilize populations within the subregion. This species is also known to occur in areas where highway project have been proposed.

Encinitas baccharis may also be threatened by a risk of extinction from naturally occurring events because of its restricted distribution and small population size. Genetic viability can be reduced in small populations, making them less adaptable to changes in the environment. Fire, drought, and severe winds could devastate whole populations in a single episodic natural event. Although swollen galls on the stems of Encinitas baccharis indicate parasitism by a moth or butterfly, insect predation on this species is not well understood.

While half of the known Encinitas baccharis populations continue to be at risk from urban development, inundation from a proposed water storage facility, and fire management methods, the species is not in immediate danger of extinction. In addition, the Multiple Habitat Conservation Plan in San Diego County will, upon its authorization, offer significant management and preservation for about half of the populations. Encinitas baccharis, for these reasons, is considered a threatened not an endangered species.

Conservation and Recovery

Fourteen populations of the Encinitas Baccharis still exist, although five of them contain less than six individuals each. One population occurs in the Cleveland National Forest. This population should be protected within the context of the Management Plan for that federal area. All other known populations occur on privately owned land, and most of them are severely threatened by development and other human influences. The critical habitat of the largest populations must be protected. This could be done by acquiring the land and establishing ecological reserves, or by negotiating conservation easements with the landowners. The known populations of the Encinitas Baccharis should be monitored, and research undertaken into its biology and habitat needs.

Contacts

U.S. Fish and Wildlife Service
Carlsbad Fish and Wildlife Office
2730 Loker Avenue West
Carlsbad, California, 92008
Telephone: (619) 431-9440
Fax: 760-431-9624

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

Reference

U.S. Fish and Wildlife Service. 7 October 1996. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for Four Southern Maritime Chaparral Plant Taxa from Coastal Southern California and Northwestern Baja California, Mexico." Federal Register 61(195): 52370-52384.

About this article

Encinitas Baccharis

Updated About encyclopedia.com content Print Article Share Article