December 2012 Number 1 - Utah Native Plant Society

Utah Native Plant Society
0.25 acres in size were documented as a point feature
and occurrences larger than 0.25 acres were mapped as
polygon features. Specific systematic methods of sampling
for the 12 rare species of interest used during the
2008 field season are shown in Table 2 (Ballard 2008).
RARE PLANT SURVEY RESULTS
Amargosa niterwort (Nitrophila mohavensis):
Listed on May 20, 1985, Amargosa Niterwort is the
only endangered plant at Ash Meadows and is restricted
to the Amargosa River drainage (Knight and Clemmer
1987). This member of the Chenopodiaceae is an extremely
hardy dwarf rhizomatous perennial that is tolerant
of high soil salinity and alkalinity. It occupies the
most localized habitat of any plant species endemic to
Ash Meadows and is often the only species present in its
habitat. N. mohavensis is found in areas with heavy salt
crusts created by evaporation of standing water. These
sites are characterized by barren, moist alkali flats with
sandy loam soils (~57% sand) encrusted with a layer of
salt with a pH near 8.4. Distichlis spicata (inland saltgrass)
is sometimes found either on the periphery, or
occasionally intermixed within Amargosa niterwort
populations (Mozingo and Williams 1980). Without ad-
equate surface water, this habitat may be taken over by
saltgrass. Reveal (1978a) noted that Amargosa niterwort
is sensitive to disturbance and does not reinvade sites
where salt crust overlying the soil has been disturbed.
Additional associated species include Atriplex confertifolia
(shadscale saltbush), Mojave seablite, and a more
widely distributed congener Nitrophila occidentalis
(boraxweed; Soil and Ecology Research Group 2004).
Two other listed species, Ash Meadows ivesia (Ivesia
kingii) and Tecopa birds beak (Cordylanthis tecopensis)
are also found in this type of habitat.
At the time of listing, the only known location for
Amargosa niterwort was Tecopa, California (Otis Bay
and Stevens Ecological Consulting 2006). Since that
time, several populations have been documented at the
Refuge and just outside its western boundary. The Nevada
Natural Heritage Program (NNHP) estimated the
population of this species across its entire range at
13,000 individuals in 1997 (Morefield 2001). According
to the recently published five-year review for the
species, the Crystal Reservoir population was estimated
at 10,000 ramets (above-ground stems), and the West
Refuge Boundary population was estimated at approximately
50 ramets (USFWS 2007b). The two popula-
Table 2. Systematic surveying protocols according to species.
Scientific Name Common Name Sampling Protocol
Arctomecon merriamii White bearpoppy Individual count census and transect method
Astragalus phoenix Ash Meadows milkvetch Transect method
Calochortus striatus Alkali mariposa lily Individual count census
Centaurium namophilum Spring-loving centaury Population census and negative sampling
Cordylanthus tecopensis Tecopa bird’s-beak Population census
Enceliopsis nudicaulis var.
corrugata
Ash Meadows sunray
84
Transect method
Eriogonum concinnum Darin buckwheat Not located
Grindela fraxinopratensis Ash Meadows gumplant Population census
Ivesia kingii var. eremica Ash Meadows ivesia Population census
Mentzelia leucophylla Ash Meadows blazingstar Individual count census and transect method
Nitrophila mohavensis Amargosa niterwort Individual count census
Phacelia parishii Parish phacelia Not located
Salvia funerea Death Valley sage Not located
Sisyrinchium spp.* Blue-eyed grass Population census
Spiranthes infernalis Ash Meadows ladies-tresses Individual count census and population census
*Includes Sisyrinchium funereum, S. halophilum, and S. radicatum.