Palmate-bracted Bird's-beak

Cordylanthus palmatus

Description

Palmate-bracted bird's-beak, Cordylanthus palmatus, is a highly branched annual that can reach 12 in (30.5 cm) in height. The glandular hairs are short and excrete salt crystals, making mature plants appear grayish-green. In all Cordylanthus species, the corolla (the set of petals) is club-shaped and is divided lengthwise into two lips (groups of fused petals that differ in appearance). The upper lip is hooked like a bird's beak and the lower lip is inflated like a pouch. The flowers are nearly hidden by bracts, which are leaf-like structures. In palmatebracted bird's-beak, the outer bracts are green; the inner bracts are lavender and deeply divided into finger-like segments. The corolla is hairy, whitish to lavender on the sides, and has fine purple stripes on the lower lip. The seeds have distinctive arching crests.

Palmate-bracted bird's-beak differs from the closely related hispid bird's-beak in that the latter has bristly hairs longer than 0.04 in (0.1 cm), whitish to yellowish lowers, and lacks crests on the seeds. Fleshy bird's-beak is distinguished from palmatebracted bird's-beak by its branching pattern and hair characteristics.

Cordylanthus species are hemiparasitic annuals, meaning that they manufacture their own food but obtain water and nutrients from the roots of other plants. Salt grass (Distichlis spicata ) is the most likely host plant for palmate-bracted bird's-beak. The combination of hemiparasitism, salt excretion, and a deep root system allows palmate-bracted bird's-beak to grow during the hot, dry months after most other annuals have died.

This species flowers from May until October. Bumblebees were the primary pollinators of palmate-bracted bird's-beak at the Springtown Alkali Sink in 1993. The bees nested in uplands more than 328 ft (100 m) distant from the population, and each bee visited only one group of palmate-bracted bird's-beak plants. Both self-and cross-pollination can contribute to seed set, and individual plants can produce up to 1,000 seeds in a single growing season. Despite the formation of a persistent seed bank, the number of plants in a population varies yearly in response to environmental conditions, particularly precipitation. Seasonal overland flooding may disperse seeds and promote seed germination by diluting the saline soils. In laboratory tests, seed germination rates were significantly higher in lowsalinity than in high-salinity solutions, regardless of alkalinity.

Habitat

This species is restricted to seasonally flooded, saline-alkali soils in lowland plains and basins at elevations of less than 500 ft (152 m). Within these areas, palmate-bracted bird's-beak grows primarily along the edges of channels and drainages, with a few individuals scattered in seasonally wet depressions, alkali scalds (barren areas with a surface crust of salts), and grassy areas. Suitability of microhabitats for palmate-bracted bird's-beak depends primarily on soil pH and to a lesser extent on soil layering, salinity, and moisture.

Distribution

Nine natural populations of palmate-bracted bird's-beak were documented between 1916 and 1982, but only two were known to survive as of 1985. As a result of intensive survey efforts and additional introductions since then, palmate-bracted bird's-beak is now known to occur in seven metapopulations: four in the Sacramento Valley, one in the Livermore Valley, and two in the San Joaquin Valley. These metapopulations are located in Sacramento National Wildlife Refuge, Delevan National Wildlife Refuge, Colusa National Wildlife Refuge, Springtown Alkali Sink, and the combined Alkali Sink Ecological Reserve, and Mendota Wildlife Management Area. The total occupied surface area over the seven metapopulations is estimated at less than 741 acres (300 hectares). The Delevan National Wildlife Refuge and Colusa National Wildlife Refuge metapopulations account for approximately 80% of the total number of individuals, and the Springtown Alkali Sink metapopulation accounts for another 19%.

Threats

Agricultural conversion eliminated palmatebracted bird's-beak populations near College City, Kerman, and southeast of Mendota; reduced the size of the Woodland population; and destroyed extensive areas of potential habitat in the Sacramento and San Joaquin Valleys. Urban development was responsible for the destruction of the Stockton occurrence.

Urban expansion, including commercial uses, residential development, and construction of recreational facilities, poses imminent threats at the Springtown and Woodland sites. Numerous other factors threaten the remaining populations. Changes in the seasonal water cycles and movements by drainage, diking, and channelization have interrupted the seasonal overland flows and altered water salinity at Springtown, Woodland, and on lands adjacent to the Alkali Sink Ecological Reserve and National Wildlife Refuges. Because of the lack of genetic variability within and among the Sacramento Valley populations and the limited number of individuals in the Alkali Sink Ecological Reserve, western Madera County, and Woodland populations, random or catastrophic events could result in elimination of the species at any of these sites. Road maintenance is a potential threat at the Alkali Sink Ecological Reserve. The Springtown metapopulation faces many additional threats, including unauthorized fill of wetlands, encroachment by exotic plant species, off-road vehicle use, and livestock wallowing in seasonal pools.

Conservation and Recovery

Since 1988, the California Department of Fish and Game has sponsored intensive research on the biology, ecology, and management of palmatebracted bird's-beak at the Springtown Alkali Sink. The first study focused on habitat characterization and resulted in development of a management plan for the area. The next series of investigations into the life history, reproductive biology, genetic composition, and site relationships were conducted by the Center for Conservation Biology and resulted in development of a long-term monitoring program for the Springtown Alkali Sink.

Personnel at the Sacramento National Wildlife Refuge (NWR) complex have contributed to conservation of palmate-bracted bird's-beak in several ways. In 1990, National Wildlife Refuge biologists established a new population at Sacramento NWR by scattering seeds that had been collected from Delevan NWR. The NWR complex avoids inundating known occurrences of palmate-bracted bird's-beak, and the hydrology and vegetation in occupied habitat are being restored to historical conditions. Refuge staff also monitor known populations on the Sacramento NWR complex annually and consider the species when any management activities are proposed or planned in occupied habitat. At least one group of plants has been fenced to restrict vehicle access and reduce the potential for trampling by waterfowl hunters.

Additional conservation efforts have included surveys and another reintroduction. The palmatebracted bird's-beak population on private land in western Madera County was discovered in 1993. A small transplant colony was established at the Mendota Wildlife Management Area in 1973 using seed collected from a nearby population that was about to be eliminated. The Endangered Species Recovery Program currently is conducting demographic studies of palmate-bracted bird's-beak at Alkali Sink Ecological Reserve. Seeds were scheduled to be collected from this population in fall 1998 for banking at a Center for Plant Conservation facility.

Contact

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

References

Chuang, T.L., and L. R. Heckard. 1973. "Taxonomy of Cordylanthus Subgenus Hemistegia (Scrophulariaceae)." Brittonia 25: 135-158.

Heady, H.F. 1977. "Valley Grassland." In M. G. Barbour and J. Major, eds., Terrestrial Vegetation of California. John Wiley and Sons, New York.

Heckard, L.R. 1977. "Rare Plant Status Report forCordylanthus palmatus." Report of the California Native Plant Society.

U.S. Fish and Wildlife Service. 1998. "Recovery Plan for Upland Species of the San Joaquin Valley, Calfornia." Region 1. Portland, OR. 319 pp.