ITIS Basic Information
Common Name: Del Mar Manzanita
Scientific Name: Arctostaphylos glandulosa ssp. crassifolia
Species Code:
Management Category: VF (species with limited distribution in the MSPA or needing specific vegetation characteristics requiring management)
Species occurrence map and table are being updated. Please check back soon.

Current Distribution Rangewide

San Diego County and Baja California, Mexico [2].

Known Populations in San Diego County

Twenty-one occurrences on Conserved Lands in MUs 4 (Mission Trails Regional Park), 6 (Carmel Mountain Preserve, City of Carlsbad Municipal Golf Course, Del Mar Highlands, Del Mar Mesa Open Space, Kelly Ranch Habitat Conservation Area, Los Penasquitos Canyon Preserve, Lusardi Creek Preserve, Manchester Mitigation Bank, Oakcrest Park, Overlook Park, Poinsettia Place, Rancho La Costa Habitat Conservation Area, San Dieguito Regional Park, The Crosby at Rancho Santa Fe), and 7 (Crest Canyon Preserve, Overlook Park, Torrey Pines State Natural Preserve).

List Status

FE [2].

Habitat Affinities

Maritime and sandy chaparral [2]. Sandstone terraces and bluffs [3]. Mesa topography in naturally fragmented habitat.

Taxonomy and Genetics

Ericaceae family [2].

Life History Demography

Perennial burl-forming evergreen shrub [2, 3]. Dependent on fire for germination [3].

Seasonal Phenology

Bloom period is December- April [2].

Pollination Seed Dispersal

Possibly can regenerate from burls and seeds [3]. Plants can produce a large number of seeds, but with large annual fluctuations [4]. Small seed bank. Flowers are self-incompatible and are visited by flies, bees, and bee-flies [4, 5]. Fruits generally fall close to parent plant where they are consumed by rodents [4]. Occasionally, seeds are eaten by foxes and coyotes and transported a distance.

Threats

Urbanization, agricultural conversion, fire and edge effects (nonnative plants, fuel modification, and human access) [3].

Special Considerations:

Easily confused with eastwood manzanita (Arctostaphylos glandulosa ssp. glandulosa) [1]. Monitored every 3 years by the City of San Diego. Buds typically sprout after fire [3].

Literature Sources

[1] Cheong, H., B. Miller, K. Martinez, P. Seiley, and M. Johnson. (2002). City of San Diego Multiple Species Conservation Program.

[2] CNPS, Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. http://www.rareplants.cnps.org, accessed 02 September 2016.

[3] U.S. Fish and Wildlife Service. (2010). ( Del Mar manzanita ) 5-Year Review : Summary and Evaluation. Carlsbad, California.

[4] Keeley, J. (1977). Seed production, seed populations in soil, and seedling production after fire for two congeneric pairs of sprouting and nonsprouting chaparral shrubs. Ecology, 58(4), 820–829.

[5] Moldenke, A. (1976). California Pollination Ecology and Vegetation Types. Phytologia, 34(4), 305–361.