Raleigh Ecological Services Field Office
Conserving the Nature of America

Seabeach Amaranth (Amaranthus pumilus)

Seabeach amaranth. Credit: Gene Nieminen.

Seabeach amaranth. Credit: Gene Nieminen.

Family: Amaranth (Amaranthaceae)

Federal Status: Threatened, listed April 7, 1993

Best Search Time: July through October (or before first tropical storm that causes overwash

Description: Seabeach amaranth is an annual plant found on the dunes of Atlantic Ocean beaches. The stems are fleshy and pinkish-red or red, with small rounded leaves that are 0.5 – 1 inch (in) (1.3 - 2.5 centimeters; cm) in diameter. The leaves, with indented veins, are clustered toward the tip of the stem and have a small notch at the rounded tip. Flowers and fruits are relatively inconspicuous, borne in clusters along the stems. Germination occurs over a relatively long period of time, generally from April to July. Upon germination, the species forms a small unbranched sprig, but soon begins to branch profusely into a clump. This clump often reaches 30 cm in diameter and consists of five to 20 branches. Occasionally, a clump may get as large as a meter or more across, with 100 or more branches.

Flowering begins as soon as plants have reached sufficient size, sometimes as early as June, but more typically commencing in July and continuing until the death of the plant in late fall. Seed production begins in July or August and peaks in September during most years, but continues until the death of the plant. Weather events, including rainfall, hurricanes, and temperature extremes, and predation by webworms have strong effects on the length of Seabeach amaranth's reproductive season. As a result of one or more of these influences, the flowering and fruiting period can be terminated as early as June or July. Under favorable circumstances, however, the reproductive season may extend into late fall. The species is an effective sand binder, building small dunes where it grows.

Habitat: Seabeach amaranth occurs on barrier island beaches, where its primary habitat consists of overwash flats at accreting ends of islands and lower foredunes and upper strands of non-eroding beaches. It occasionally establishes small temporary populations in other habitats, including sound-side beaches, blowouts in foredunes, and sand and shell material placed as beach replenishment or dredge spoil. Seabeach amaranth appears to be intolerant of competition and does not occur on well-vegetated sites. The species appears to need extensive areas of barrier island beaches and inlets, functioning in a relatively natural and dynamic manner. These characteristics allow it to move around in the landscape as a fugitive species, occupying suitable habitat as it becomes available.

map of Seabeach amaranth distribution in North Carolina

Map of Seabeach amaranth distribution in North Carolina.

Distribution: Historically, Seabeach amaranth occurred in nine states from Massachusetts to South Carolina. The species is currently found in New York, New Jersey, Delaware, Maryland, Virginia, North Carolina, and South Carolina.

Threats: The most serious threats to the continued existence of Seabeach amaranth include the construction of beach stabilization structures, beach erosion and tidal inundation, beach grooming, pedestrian traffic, herbivory by insects and feral animals and, in certian circumstances, by off-road vehicles.

References:

Buchanan, M.F. and J.T. Finnegan. 2010. Natural Heritage Program List of the Rare Plant Species of North Carolina. NC Natural Heritage Program, Raleigh, NC.

U.S. Fish and Wildlife Service. 1996. Recovery Plan for Seabeach Amaranth (Amaranthus pumilus). Rafinesque. Atlanta, GA 59 pp.

For More Information on Seabeach Amaranth...

Species Contact:

Dale Suiter, Fish and Wildlife Biologist, 919-856-4520 ext. 18

Species profile revised on July 26, 2011.

Last Updated: November 1, 2012