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Beach Layia

Layia Pickart 512This short annual herb can be found at only eight dune systems between Humboldt County and Santa Barbara County.

Identifying Characteristics:  
Beach layia is a succulent, annual herb belonging to the sunflower family (Asteraceae).  The plant can range from a silver dollar-size single stem, to a many-branched tuft up to 6 inches tall and more than 16 inches in breadth.  Characteristics distinguishing beach layia from similar species include its very succulent leaves, inconspicuous flower heads with short 0.08-0.1 inch white ray flowers and yellow disk flowers, and bristles around the top of the one-seeded achene (dry fruit).  The number of seed-heads on individual plants varies with plant size.  Typically unbranched, short plants on dry, exposed sites may produce only a single head, while highly branched plants in moist dune hollows may produce more than 100 flower heads.
 
Current Geographic Range:  
Beach layia is currently known from approximately 20 occurrences representing eight dune systems, located between Freshwater Lagoon in Humboldt County and Vandenberg Air Force Base in Santa Barbara County.  Five historical occurrences located in San Francisco, Monterey and Humboldt counties are believed extirpated.   Humboldt County reportedly contains the largest populations and acreage of occupied habitat.  Current Humboldt County occurrences, from north to south, include Freshwater Lagoon (Redwood National Park; less than one acre), Mad River Dunes area (private and Humboldt Bay National Wildlife Refuge), Samoa Peninsula/North spit (private, BLM and Humboldt County), South Spit (BLM managed), Eel River Wildlife Area (CDFG), the vicinity of McNutt Gulch (private) and the mouth of the Mattole River (BLM).  The Marin County occurrences are located in the dunes between Kehoe Beach Dunes and Point Reyes lighthouse at Point Reyes National Seashore.  The four Monterey County sites are located on the Monterey Peninsula, although the Point Pinos site may have been extirpated.  An occurrence thought to be extirpated at Asilomar State Beach was rediscovered following the removal of non-native iceplant.   In April 1995, a small occurrence of beach layia was also relocated at Vandenberg Air Force Base in Santa Barbara County. 
 
Life History:  
Beach layia seeds are dispersed by wind mostly during late spring and summer months.  Little is known about the pollination ecology of beach layia.  As a winter annual, beach layia germinates during the rainy season between fall and mid-winter, blooms in spring (March to May), and completes its life cycle before the dry season.  Populations tend to be patchy and subject to large annual fluctuations in size.  Dynamic changes in local population distribution are associated with shifts in wind erosion patterns, remobilization, and natural dune stabilization that occur in the coastal dune ecosystem. Colonies often establish in areas where sparse vegetation serves to trap wind-dispersed seeds with little shading effect.
 
General Habitat Characteristics:  
Beach layia is restricted to openings in coastal sand dunes ranging in elevation from 0-100 feet, where it colonizes sparsely vegetated, semi-stabilized dunes and areas of recent wind erosion.  In most of its range the species occurs in the nearshore dunes, in open and low vegetation such as the sand-verbena - beach bursage series described by Sawyer and Keeler-Wolf (1995).  Beach layia also occurs in lower densities along margins of lupine scrub, herbaceous hollows, and open areas with moving sand.  Common associated species include: coast buckwheat, beach pea, beach sandwort, dune bluegrass, dune goldenrod, sand verbenaand beach-bur.  The species often occurs in open, semi-disturbed areas adjacent to trails and roads.   Beach layia readily colonizes newly created bare sand areas, and is resilient to disturbance.  However, it generally does not establish or survive for long in areas where there is high cover of either native or non-native plants.
 
Population and Habitat Status: 
No scientifically valid estimate has been made of the total number of beach layia individuals.  Mostly informal estimates of populations made across the range prior to 1998 totaled some 300,000 plants, but the historical data are of limited value due to the capability for very large fluctuations in population size, and frequent underestimation of population size typical of small, annual plant species.  A statistically-based estimate of  2.5 million plants was made for the population existing on the North Spit of Humboldt Bay in 1992.  The population located on the South Spit of Humboldt Bay was estimated in 2003 at about 3 million plants scattered within about 34 acres of occupied habitat.   Redwood National Park personnel estimated the beach layia population at Freshwater Spit in 2003 at just over 11,000 plants.  Based on these estimates, the total number of beach layia occurring around Humboldt Bay and farther north may exceed 5 to 6 million.  Population estimates for sites located south of Humboldt Bay are not available.  
 
Absence of beach layia in habitat surrounding extant populations is most often due to the presence of exotic species, which stabilize the dune system and crowd out pioneer species such as the beach layia.  Humboldt Bay is considered to have the largest amount of habitat, and highest quality habitat for the beach layia, due to the relative high proportion of open dunemat to dune scrub, and perhaps the relatively high amount rainfall compared to the rest of the range. 
 
Threats:  
Beach layia is threatened by loss of habitat due to coastal development, encroachment of non-native plant species, and trampling by off-road vehicles and pedestrians. Beach layia is most susceptible to trampling effects during its growing season from mid-winter to late spring.  Annual monitoring at Lanphere Dunes, near Humboldt Bay, indicated population densities of beach layia generally declined between 1989 and 1997, with a relatively small increase in 1998.  Densities were significantly higher in restored areas where European beachgrass had been removed and cover of open sand was higher.
 
Faced with increasing recreational use and development pressure within the coastal dunes of California, and the widespread encroachment into its habitat by invasive species, ensuring the future survival of beach layia may be a challenge.  Fortunately, some kinds of disturbance during the off-season are actually beneficial for the plant by opening up areas for colonization.  Nevertheless, barring large-scale natural disturbances, direct human intervention and management may be necessary to maintain and restore the early successional conditions needed by this and the many other rare plants occupying the coastal dunes across California over the coming decades. 
 
Conservation Needs: 
The Federal recovery plan for beach layia includes various tasks necessary to minimize the threats to the species and its habitat, reclassify it to threatened status, and eventually delist the species after a minimum of 20 years.
 
Reclassification to threatened status may be considered when: 
 
• Habitat occupied by the beach layia and identified in the recovery plan as necessary for delisting is secured with long-term commitments and, if possible, endowments to fund conservation of the native vegetation;
• Management has been implemented to address the threat posed by invasive species, pedestrians, and off-road vehicles at selected sites;
• Monitoring indicates that management actions have been successful in reducing threats of invasive non-native species;
• Additional restored habitat is occupied by stable populations of beach layia, through either natural or artificial means, and is protected through permanent commitments and endowments, where possible, enabling habitat maintenance in perpetuity.
 
Beach layia may be delisted when: 
 
• The Humboldt Bay dune system (north and south spits) is relatively free of European beachgrass along the foredune, and iceplant, yellow bush lupine, and pampas grass are greatly reduced; degraded dunes are restored, and vehicle management is implemented, including fencing and/or patrolling where needed; new colonies of beach layia are established and persist for at least 10 years; and monitoring for at least 15 years demonstrates that beach layia is increasing in response to the availability of restored habitat. There must be written assurance supporting continued management of the dunes and biological monitoring.
• The population at Point Reyes National Seashore is expanded in response to the same measures described for the Humboldt dunes.
• Beachgrass and iceplant control measures are implemented at the Monterey Bay and Vandenberg dune systems, and populations are maintained with more than 5,000 individuals per site.
 
In summary, recovery and delisting of beach layia will be achieved when the dune systems it inhabits are restored, and monitoring indicates exotic plants and other threats such as recreational use, off-road vehicles, etc. are controlled.  Beach layia must be secure in its current occupied habitat, and opportunities should be taken to introduce the species to restored habitat in or near historic ranges.  To be counted toward recovery, (re)introduced populations should be naturally reproducing in vegetation that is considered stable (i.e., persists in absence of excessive maintenance).   Delisting should be based on not less than 15 years of monitoring data, to include both wet and drought years. 
 

For more information about Beach Layia click here .

Last Updated: Mar 06, 2013
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