Beach Layia

Layia carnosa

Description

The beach layia, Layia carnosa, is a low growing (less than 6 in [15 cm]), succulent, glandular winter annual. This plant can be unbranched to highly branched, spreading to more than 16 in (40 cm) across. The sticky fleshy leaves are 0.08-0.1 in (2-2.5 mm) long. The ray flowers are white, and the bristles about the summit of the achene differentiate this taxa from other species of Layia.

This winter annual germinates during the rainy season from fall to mid-winter, blooms April to June, and completes its life cycle before the dry season. It tends to grow in patches, and occurrence numbers vary annually, both spatially and temporally. Colonies often occur where sparse, open vegetation traps wind-dispersed seeds, but causes minimal shading.

The number of seed heads on individual plants varies with plant size, ranging from unbranched, short, erect plants with a single head found on dry, exposed sites; to highly branched plants with more than 100 heads found in moist hollows in dunes. Seeds are dispersed by wind mostly during the late spring and summer months. Nothing is known about the pollination ecology of beach layia. Populations of beach layia are subject to large fluctuations in size and dynamic changes in local distribution, consistent with the shills in dune blowouts, remobilization, and natural dune stabilization that occur in the coastal dune ecosystem.

Habitat

The species is restricted to openings in coastal sand dunes ranging in elevations of 0-100 ft (0-30 m), where it colonizes sparsely vegetated, partially stabilized dunes or relatively bare blowouts in secondary succession. In northern California, it occurs in the northern foredune community; in Monterey County, the species occurs in the central foredune community described as the sand-verbena-beach bursage. It generally occupies sparsely vegetated open areas on semistabilized dunes. The foredune community experiences some drifting sand and has low-growing herbaceous and perennial native species. The species also occurs in open areas, such as along trails and roads.

The cover of associated vegetation protects the species from sand dune movement and erosion. Associated species include coast buckwheat, beach pea, beach sagewort, dune bluegrass, dune goldenrod, sand verbena, and beach-bur.

Distribution

Until late twentieth-century surveys were conducted, 17 occurrences of beach layia had been found in seven dune systems from Santa Barbara County to Humboldt County. It is rather certain that some occurrences were extirpated or reduced in size before they could be surveyed. As of the late 1990s, this species was known from 19 extant occurrences with 300,000 individuals. Five of the historical occurrences in San Francisco, Monterey, and Humboldt Counties are thought to be extirpated.

The largest occurrences are in Humboldt County. Three of the historic Humboldt County occurrences were on the Samoa Peninsula in the Humboldt Bay dune system; two of them have been extirpated. The extirpated occurrences were in the Little River area of Humboldt County; the northernmost occurrence was probably removed when the river mouth naturally meandered north, eliminating the dune flora that was collected in the early twentieth century. The second extirpated occurrence was lost to the construction of Highway 101 and the invasion of non-native plants in the 1960s. Other Humboldt occurrences include one associated with dunes at the mouth of McNutt Gulch, and one in dunes south of the Mattole River.

The Marin County occurrences are located in the dunes between Kehoe Beach Dunes and Point Reyes lighthouse at Point Reyes National Seashore. Surveys by California Native Plant Society volunteers have recorded 13 colonies along the dune complex at Point Reyes National Seashore.

The San Francisco Peninsula occurrence was found on the dune habitat in Golden Gate Park. Last collected from that area in 1904, the species has been extirpated from this intensely surveyed area, probably because the dunes were developed for Golden Gate Park and the urbanization of San Francisco. At the time of the last collection, San Francisco dune reclamation projects had been in progress for more than 30 years, so it is possible that other localities were eliminated without detection.

The Monterey Peninsula dune system had four occurrences, although the Point Pinos site, the type locality, is thought to have been extirpated. After it had been reported to be extirpated, an occurrence at Asilomar State Beach was rediscovered following the removal of ice plant. Additional occurrences have been discovered on neighboring private property. Two beach layia occurrences exist on north Spyglass Hill and on the nearby Spyglass Hill dunes.

In 1995, 80 plants were rediscovered on Vandenberg Air Force Base. During a subsequent visit to the site an additional 200 individuals were discovered closer to the ocean bluffs.

Threats

The threats to beach layia are displacement by invasive, non-native vegetation, recreational uses such as off-road vehicle activities and pedestrians, and urban development.

In Humboldt County, beach layia is threatened by invasive non-native species that were used to stabilize dunes, including yellow bush lupine, European beachgrass, and ice plant. Occurrences on the Samoa Peninsula are also threatened by industrial development and off-road vehicle activity. The resurgence of off-road vehicle trespassing, which has resulted from inadequate enforcement of existing ordinances, is a serious problem. Recovery may not be feasible without adequate funding to enforce laws designed to protect sensitive resource areas in the dune systems. The problem is magnified by the fact that a private off-road vehicle club is located between U. S. Bureau of Land Management (BLM) and U. S. Fish and Wildlife Service properties in the most ecologically valuable habitat on the north spit. Dispersal of invasive plants mentioned earlier as well as pampas grass is occurring onto adjacent managed lands.

The occurrence in the Kings Range National Conservation Area is managed by the BLM. This occurrence was threatened by off-road vehicle use and cattle grazing, but is now protected by newly reconstructed fencing and strict conditions on grazing.

The Mattole River occurrence is on private land north of the river, and is threatened by cattle grazing and displacement by European beachgrass.

Marin County occurrences are primarily threatened by the invasion of European beachgrass, and, to a lesser extent, ice plant. These occurrences are affected to a small extent by grazing from deer, hares, and rabbits. Cattle grazing is not an impact in the Abbotts-Kehoe area.

Monterey County occurrences have low numbers of individuals and are threatened primarily by invasive non-native plants and encroaching development. The threats are similar to those facing the Monterey spineflower.

The Santa Barbara County occurrence is adjacent to a road on Vandenberg Air Force Base. The primary threats to this occurrence are construction and road maintenance, including the installing of a pipeline, road paving, and controlling vegetation by mowing and spraying with herbicides. During road maintenance operations in 1997 half of the rediscovered site was destroyed.

Conservation and Recovery

The Humboldt County Local Coastal Program prohibits vehicles above the wave slope except in the Samoa Dunes Recreational Area. The county has recently adopted a management plan for the north and south spits of Humboldt Bay. The north spit area supports Erysimum menziesii ssp. eurekense and beach layia. The plan designates certain areas for vehicular access on the beach and dunes as well as vehicle-free zones. This plan addresses access on public lands as well as access to and from adjacent BLM lands, private lands, and the Lanphere Dunes. The plan recommends restoring degraded dunes, including removal of invasive, non-native plant species; fencing of rare plant habitat; and limiting public access.

In Humboldt County, the Lanphere Dunes is fenced and patrolled to control trespass by off-road vehicle users. The Nature Conservancy has conducted native plant restoration activities on the north spit of Humboldt Bay. Exotic plant removal in the dunes has resulted in colonization of the openings by beach layia.

One occurrence on the Samoa Peninsula occurs on land managed by the BLM and the City of Eureka. The BLM manages the property and has fenced an area for the protection of beach layia. Degradation of habitat continues on the adjacent City of Eureka land. Although the city has zoned the site as a mitigation bank, protective measures have not been implemented. The BLM has an extensive occurrence on its Manila Dunes Area of Critical Environmental Concern and Research Natural Area and has funded weed control through its Partners against Weeds Initiative. Continued financial support for dune restoration will be needed to recover the species.

Various individuals have collected seed under the authority of a memorandum of agreement with the California Department of Fish and Game. The Pebble Beach Company collected achenes from the beach layia occurrence on its land. The achenes were sent to the State Endangered Plant Program for banking some years ago but the collecting and out-planting has ceased. The seeds sent to the Plant Conservation Program were transmitted to the Rancho Santa Ana Botanic Garden for long-term storage in 1990. Leslie Gottlieb, professor of genetics at the University of California, Davis, has collected achenes for research that to date focuses on the study of gene duplications.

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
Sacramento Fish and Wildlife Office
Federal Building
2800 Cottage Way, Room W-2605
Sacramento, California 95825-1846
Telephone: (916) 414-6600
Fax: (916) 460-4619

References

U. S. Fish and Wildlife Service. 22 June 1992. "Six Plants and Myrtle's Silverspot Butterfly from Coastal Dunes in Northern and Central California Determined to Be Endangered." Federal Register 57 (120): 27848-27858.

U. S. Fish and Wildlife Service. 1998. "Recovery Plan for Seven Coastal Plants and the Myrtle's Silverspot Butterfly." Portland, Oregon, 141 pp.