Endangered Species Recovery Program

1. Lesser Saltscale (Atriplex minuscula)

• Taxonomy
• Description
• Historical Distribution
• Current Distribution
• Life History and Habitat
• Reasons for Decline and Threats to Survival
• Conservation Efforts
• Conservation Strategy

1. Lesser Saltscale (Atriplex minuscula)

Taxonomy.-- Lesser saltscale is a member of the goosefoot family (Chenopodiaceae). Standley published the name Atriplex minuscula in 1916. The name was not widely accepted, and for many years lesser saltscale was considered to be merely a variant of Parishs brittlescale (A. parishii) that did not warrant recognition (Abrams 1944, Munz and Keck 1959). However, Taylor and Wilken (1993) considered lesser saltscale to be a valid species and have returned to using the name A. minuscula.

Description.-- Lesser saltscale has many upright, reddish stems up to 40 centimeters (16 inches) tall. The leaves are egg-shaped with entire (untoothed) margins and typically are opposite on the upper branches and alternate on the lower part of the stem. The individual flowers of all Atriplex species are inconspicuous because they are tiny and have no petals; moreover, the male and female structures are produced in separate flowers. In lesser saltscale, both flower genders occur in the leaf axils (the points where leaves are attached to the stem), with the male flowers on the upper part of the stem and the females near the base of the same plant (Munz and Keck 1959). Each fruit consists of a single reddish seed that is enclosed by two egg- to diamond-shaped bracts, which are covered with tubercles (wart-like projections). The closely-related species brittlescale (Atriplex depressa) and Parishs brittlescale have stems and branches that lie close to the ground, unlike the erect stems of lesser saltscale, and differ in bract characters (Taylor and Wilken 1993).

Historical Distribution.-- Herbarium specimens of lesser saltscale were collected historically only at Goshen (Tulare County) in 1905 and El Nido (Merced County) in 1936 (CDFG 1995).

Current Distribution.-- Neither of the historical sites has been checked to determine if lesser saltscale remains extant, though no significant patch of natural land exists in either area. In 1993, lesser saltscale was discovered at five new localities in the San Joaquin and Sacramento Valleys (Figure 17). The southernmost report was from Kern County, near the intersection of Interstate 5 and state Highway 58, and the northernmost was at Gray Lodge Wildlife Area in Butte County (CDFG 1995). Lesser saltscale also was reported from the Kerman Ecological Reserve in Fresno County (CDFG 1995), Arena Plains National Wildlife Refuge in Merced County (Silveira 1996), and along the Fresno River in Madera County (D. Mitchell pers. comm.).

Figure 17. Distribution of lesser saltscale (Atriplex minuscula).

Life History and Habitat.-- The life history of lesser saltscale is poorly known, except that it is an annual and flowers from May to October (Skinner and Pavlik 1994). Lesser saltscale grows on sandy soils in alkaline areas at elevations of less than 100 meters (330 feet), often in association with slough systems and river floodplains. However, it is found only in microhabitats that are not inundated year-round. The species has been found in the Valley Sink Scrub, Valley Sacaton Grassland, and Nonnative Grassland natural communities. Lesser saltscale grows with other halophytes, including alkali sacaton, brittlescale, heartscale (Atriplex cordulata), and seepweed (CDFG 1995, D. Mitchell pers. comm., D. Taylor pers. comm.).

Reasons for Decline and Threats to Survival.-- The lack of historical information about lesser saltscale prohibits a determination of whther or not it has declined. However, the conversion of alkali sinks to agriculture undoubtedly has reduced potential habitats (Skinner and Pavlik 1994). The extant population in Kern County is on land that is zoned for commercial development and which is for sale (CDFG 1995). The Madera County site is threatened by installation of a pipeline (D. Mitchell pers. comm.). Sites on state Wildlife Management Areas are threatened by flooding for waterfowl management (D. Taylor pers. comm.).

Conservation Efforts.-- Lesser saltscale has not been the target of conservation actions. However, it may have benefited indirectly from land acquisition for other species, such as the Tipton kangaroo rat. Lesser saltscale could occur on USBLM lands in alkali sink areas (USBLM 1993) or on CDFGs Buttonwillow Preserve, which is near the known Kern County site and which includes similar habitat.

Conservation Strategy.-- To ensure the long-term conservation of lesser saltscale, the strategy is to protect at least five populations representing the full geographic range of the species. Protected areas should be natural land in blocks of at least 65 hectares (160 acres) and should contain a minimum of 1,000 individuals to reduce the likelihood of extinction from intrinsic or random processes. The highest-priority tasks for lesser saltscale are to survey historical sites and suitable habitat and to protect extant populations from development and other threats. All remaining unconverted alkali sinks in the Central Valley should be surveyed, and threats to any populations that are found must be evaluated. Surveys for lesser saltscale can be conducted concurrently with those for other rare plants that occur in alkali sinks, particularly palmate-bracted birds-beak. Landowner cooperation is necessary to ensure protection on private lands, and the cooperation of public agencies is crucial on lands under their control. Moreover, threats must be alleviated in protected areas to ensure the continued survival of the species, and monitoring will be required to verify that populations are remaining stable. Seeds should be salvaged from any populations that are scheduled to be destroyed by development. When surveys have been completed, or at a maximum within 5 years of recovery plan approval, the status of lesser saltscale should be reevaluated.