Species Fact Sheet Malheur wire-lettuce Stephanomeria malheurensis
STATUS: ENDANGERED CRITICAL HABITAT: DESIGNATED
Malheur wire-lettuce potentially occurs in these Oregon counties: Harney (Map may reflect historical as well as recent sightings)
Malheur wirelettuce was federally listed as endangered with critical
habitat in 1982 (U.S. Fish and Wildlife Service 1982). A recovery
plan was published in 1991 (U.S. Fish and Wildlife Service 1991).
Historical Status and
The first discovery of Malheur wirelettuce was in 1966 when seeds
of this species were collected with those from a population of
its ancestral plant, small wirelettuce.
This species is an annual and its numbers vary greatly from year
to year, depending largely on the amount of precipitation prior
to and during the spring growing season. In 1974, the population
was estimated at 228 plants and in 1975 the numbers grew to 1,050.
During the 1980's, very low numbers of plants were found, and
in 1985, 1986 and 1999, no plants were observed. During this time
when the species numbers dwindled to zero, cheatgrass (Bromus
tectorum) an extremely aggressive non-native grass species dramatically
increased at the site. A reintroduction program was begun in April
1987 and 1000 seedlings obtained from the Berry Botanic Garden
were transplanted into study plots at the site. Of these plants,
412 survived and one wild plant was found. During subsequent years,
efforts have been undertaken to remove cheatgrass from around
existing plants and study plots; however, numbers of Malheur wirelettuce
Description and Life
Malheur wirelettuce is an annual plant in the composite family
(Asteraceae). It can reach 5 dm (20 inches) in height. This species
forms a rosette of hairless leaves that arise from its base. The
single stems are many-branched with scale-like leaves. Flower
heads are either numerous and clustered, or solitary on short
stems. The strap-shaped petals are pink, white, or rarely orange-yellow.
Flowering typically occurs in July and August.
The Malheur wirelettuce is co-located with an ancestral relative,
small wirelettuce (Stephanomeria. exiqua ssp. coronaria); however,
the two species do not interbreed. While the Malheur wirelettuce
is self-pollinating, its ancestral relative is not.
Malheur wirelettuce occurs in the high desert of the northern
portion of the Great Basin and is located in an area south of
Burns, Oregon. It occurs on top of a dry, broad hill on volcanic
soil intermixed with layers of limestone. Dominant plants at the
site are big sagebrush (Artemisia tridentata), gray rabbitbrush
(Chrysothamnus nauseosus), green rabbitbrush (Chrysothamnus viscidiflorus),
and, more recently, cheatgrass. Malheur wirelettuce may be one
of the few species able to survive on and around the otherwise
barren harvester ant hills at the site.
Reasons for Decline
Malheur wirelettuce is in great danger of extinction due to its
small population size. Natural fluctuations in population numbers
that occur in response to variations in annual rainfall and spring
frosts are particularly problematic for small populations. The
species is also vulnerable to habitat alteration; surface mining
for zeolite was a potential threat at the time of listing. Other
immediate threats include competition from cheatgrass and predation
by native herbivores such as black-tailed jackrabbits.
Critical habitat for Malheur wirelettuce was designated at the
time of listing in 1982. This designation identifies the specific
area containing the necessary physical and biological requirements
for the conservation of the species. The designation of critical
habitat provides additional protection for the species. The area
within the designated critical habitat was set aside to allow
for natural expansion of the population and to provide a buffer
against potential adverse impacts from activities on adjacent
lands. In 1984, the Bureau of Land Management (BLM) designated
the known location of Malheur wirelettuce as the South Narrows
Area of Critical Environmental Concern. The 160-acre area has
been fenced since 1974 to prevent grazing by livestock. Monitoring
of Malheur wirelettuce population is regularly conducted by BLM
In 1986 the Service completed the Malheur Wirelettuce Recovery
Plan which identified various tasks that are necessary to recover
the species. The primary tasks are to maintain and enhance existing
populations and habitat, conduct systematic searches for new populations,
secure any newly found populations, and develop management and
monitoring programs for the species. The U.S. Fish and Wildlife
Service, in cooperation with the BLM, developed the "Study
Plan for Stephanomeria malheurensis" to identify research
needs and management options for the maintenance of a viable self-perpetuating
population of Malheur wirelettuce.
Malheur wirelettuce occurs at only one location on approximately
70 acres of public lands managed by the BLM.
References and Links
U.S. Fish and Wildlife Service. 1982. Determination of Stephanomeria
malheurensis (Malheur wirelettuce) to be an Endangered Species,
With Determination of Critical Habitat. Federal Register 47:50881-50886. https://ecos.fws.gov/docs/frdocs/1982/82-30881.pdf