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Arenaria paludicola Robins.
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photo by Dr. Malcolm McLeod
Synonyms
Minuartia
paludicola
House
Alsinopsis paludicola A. Heller
Arenaria
palustris
S. Watson (not A. palustris Gay)
Alsine
palustre
Kellogg
Status
Federally Endangered
(Listed: August 3, 1993)
Possibly extinct or extirpated in Washington
Endangered in Oregon and
California (Listed: Feb. 1990)
Description
The
plant is a perennial
herb that has flaccid stems and is therefore often supported by surrounding
vegetation. According to the Jepson
manual, the stems have angled or grooved stems, which are glabrous except at
the nodes. The trailing stems often
root at the nodes and can be up to one meter long. The leaves of the plant are opposite, lanceolate and narrowly
acute, with a solitary mid-vein. It can
be found in bloom between May and August, and the flowers are small, solitary
and white, borne on a long stalk that arises from the axils of the leaves. One capsule often contains 15-20 seeds.
Habitat
Arenaria
paludicola grows mainly in wetlands and freshwater marshes in a mediterranean
(cool, wet winters and dry, warm summers) climate. The species grows from sea level to 450
meters (1476 feet). The plant can grow
in saturated acidic bog soils and soils that are sandy with a high organic
content.
Distribution Three populations are known in
California though the species was once distributed throughout wetland areas in
Washington, Oregon and California. The known remaining populations are found in
San Luis Obispo County and Mendocino County. (distribution maps for California
are available through CalFlora)
Overview
Arenaria
paludicola was once distributed along the coast of the western United
States from Washington, south through Oregon to the Nipomo Dunes in San Luis
Obispo County in California. As of May
14, 2001, the only
remaining populations were located in California. One population is thought to be located in southern San Luis
Obispo County at Black Lake Canyon on the Nipomo Mesa, one at Oso Flaco Lake
(also in San Luis Obispo County) and the other in MacKerricher State Park,
Mendocino County. There are contrasting
reports on the number of populations currently found. Some sources claim that only one population is known (in Black
Lake Canyon) and that the other populations have become extinct.
The species was first named
in 1863 as Alsine palustre and described as an abundant swamp species by
Albert Kellogg. In 1876, the species
was reassigned (by Sereno Watson) to the genus Arenaria, thus becoming Arenaria
palustris, not realizing that another species had already been given the
same name. A. palustris was then
given it’s current name, A. paludicola.
A recovery plan has been put into effect by the government, and has been listed by the federal government with a recovery priority listing of 5. This means that there is a high threat of extinction and a low potential for recovery. The main objective for the recovery of swamp sandwort is to secure viable, self-sustaining populations of the species in its natural habitat. There are six major steps in the recovery plan: protect, maintain, and enhance the species’ habitats; monitor and document the species’ populations and habitat characteristics; conduct research on the ecology and biology of the species; increase existing populations; establish new populations; and evaluate progress and update management and recovery guidelines.
Threats There are numerous reasons behind A. paludicola’s decline, which are also the main threats to its continued existence. The wetlands in which the species grows are slowly being eliminated and/or degraded through urban development, conversion of the habitat for agriculture and ranching activities, and off-road vehicle recreational use. In addition, the hydrology of the habitat is slowly being altered as more and more water is being drawn away from the water table from well-drilling, water uptake and recent drought. The species also has to compete with alien and native species that are more efficient in this changing environment. In addition, the small number of individuals and populations remaining are at greater risk of extinction due to stochastic events.
Sources
CalFlora elib.cs.Berkeley.edu/cgi/calflora_query?special=calflora&where-calrecnum=652&one=T
Fish
and Wildlife Service http://endangered.fws.gov/frpubs/n970623a.pdf
Fish and Wildlife Service http://endangered.fws.gov/recovery/recplans/
Hickman, J.C. 1993. The Jepson Manual, higher plants of California. University of California Press, Berkeley.
Hitchcock,
C.L. and A. Cronquist. 1991. Flora of the Pacific Northwest. University
of Washington Press, Seattle.
Land Conservancy of San Luis Obispo County http://www.special-places.org/blc.htm
US
Fish and Wildlife Service http://www.ccfwo.r1.fws.gov/marshsandwort.html
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1994).
1994).