Download White-margined_beardtongue

DRAFT
March 2012
PLANTS
White-Margined Beardtongue (Penstemon albomarginatus)
White-Margined
Beardtongue
(Penstemon
albomarginatus)
Legal Status
State: S11
Photo courtesy of Makela Mangrich.
California Rare Plant Rank: 1B.12
Federal: Bureau of Land Management Sensitive
Critical Habitat: N/A
Recovery Planning: N/A
Taxonomy
White-margined beardtongue (Penstemon albomarginatus) is a
member of the plantain family (Plantaginaceae), formerly included in
the figwort family (Scrophulariaceae) (Jepson Flora Project 2011).
M.E. Jones first described the species in 1908 (as cited in Anderson
1999). The taxonomic status of white-margined beardtongue is
unique and it has never been confused with any other species of
Penstemon (Anderson 1999), nor is it believed to hybridize with other
species in the genus (Etyemezian et al. 2010).
This perennial herb is 15 to 35 centimeters (5.9 to 13.8 inches) tall
(CNPS 2011; Jepson Flora Project 2011). Descriptions of the species’
physical characteristics can be found on the Jepson eFlora (Jepson
Flora Project 2011), and in MacKay (2006) and Anderson (1999).
Distribution
General
White-margined beardtongue is known from only four general
locations: two in the Mojave Desert of Southern Nevada, one in the
1
2
S1: Critically imperiled.
1B: Rare, threatened, or endangered in California and elsewhere. X.1: seriously threatened in California.
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White-Margined Beardtongue (Penstemon albomarginatus)
Mojave Desert of southeast California, and one in the Sonoran Desert
of northwest Arizona (Smith 2001, cited in Etyemezian et al. 2010).
Its distribution in California is restricted to eastern San Bernardino
County (CDFG 2012a), within the following quadrangles (listed from
west to east): Troy Lake, Hector, Lavic Lake, Sleeping Beauty, Ludlow,
and Cadiz Summit. The majority of the 23 occurrences documented in
the California Natural Diversity Database (CNDDB), all of which are
within the Plan Area (CDFG 2012a), are located north of Interstate 40,
including a large population occurring in a 4-mile-long wash
northeast of Pisgah Crater, extending southwest from Sleeping Beauty
Peak, and terminating in a flat spreading basin south of the freeway
(CDFG 2012a; MacKay 2006). The species is also found in another
wash extending south–southeast from Sleeping Beauty Peak, and in a
number of smaller locations mapped since 2008 west of there in the
vicinity of Hector (CDFG 2012a). South of Interstate 40, the species
has been documented in the vicinity of Lavic Lake and Swede Hill
(southeast of Lavic Lake) (CDFG 2012a).
Figure SP-P35 shows the range of white-margined beardtongue in
California.
Distribution and Occurrences within the Plan Area
Historical
Five CNDDB occurrences were originally recorded prior to 1990,
although they are all presumed extant (CDFG 2012a). The three oldest
records, from 1935 to 1940, are located (1) in the vicinity of Lavic Lake;
(2) south of Swede Hill, east of Lavic Lake; and (3) near the western
junction of Interstate 40 and Highway 66 in the Ludlow quadrangle.
These three records have not been updated since then. The two
remaining records, last updated in 1989, are located (1) in the Cadiz
Summit quadrangle in the vicinity of Highway 66, and (2) in a wash
extending south and southeast of Sleeping Beauty Peak on land
managed by the Bureau of Land Management (BLM). The Cadiz Summit
occurrence was added by the California Department of Fish and Game
as a “best guess” based on a 1941 collection that documented whitemargined beardtongue plants “between Cadiz and Danby.” The site was
searched by Scogin in 1989 and later by J. Andre, but neither botanist
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White-Margined Beardtongue (Penstemon albomarginatus)
observed white-margined beardtongue in this location. Scogin noted
that there is “too much gravel cover, sand is too shallow” (CDFG
2012a). This occurrence needs additional field work.
Recent
Eighteen CNDDB occurrences have been observed since 1990, 16 of
which are documented on BLM land (CDFG 2012a). Ownership of the
land for the two remaining records observed since 1990 is unknown.
All 18 of these records are located east of the Newberry Springs area
at the western edge of the known range of the species in California
and are presumed extant.
Figure SP-P35 provides an overview of the species model for whitemargined beardtongue, with these occurrences overlaid (CDFG 2012a).
Natural History
Habitat Requirements
The CNDDB element occurrence information cites the habitat
requirements of white-margined beardtongue as Mojave Desert scrub
and desert dunes, specifically in deep, stabilized desert sand, and in
washes and along roadsides (CDFG 2012a). Within California, Andre
(2010) notes that this species occurs on mostly “fine alluvial sands
within a sparse creosote bush scrub community.”
White-margined beardtongue occurs from 635 to 1,065 meters (2,083
to 3,494 feet) (CDFG 2012a). There are additional records in the
Consortium of California Herbaria that, if verified, would extend this
elevation range to as low as 426 meters (1,398 feet) (Jepson Flora
Project 2011).
Etyemezian et al. (2010) studied white-margined beardtongue habitat
requirements in the Nevada populations over the course of 2 years,
with particular emphasis on the effects of eolian, fluvial, and dust
deposition processes on white-margined beardtongue populations.
Some of their findings include:

All of the study sites where white-margined beardtongue was
present were characterized as sandy (>80% sand, >85% at
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White-Margined Beardtongue (Penstemon albomarginatus)
surface) to a depth of at least 60 centimeters (24 inches), having
slopes in the range of 1.8%–4.6% with aspects (facing direction) in
the range of 174–309 degrees from north;

Sandy soils with shrub covers of less than 20% and an
accumulation of surface carbonates in the canopy inter‐spaces
appear to provide the best habitats for healthy white-margined
beardtongue populations;

The Bluepoint and Arizo soil series supported the healthiest
populations in both Clark and Nye Counties (Nevada), and
wherever these soils occur, the possibility of discovering new
white-margined beardtongue populations exists; and

Results of a cluster analysis of the study sites indicated that for
Clark County, the native perennial grass, big galleta (Hilaria
[Pleuraphis] rigida), and the native shrubs, winter fat
(Krascheninnikovia
lanata)
and
Shockley’s
goldenhead
(Acamptopappus shockleyi), are the most likely indicator species
for the presence of white-margined beardtongue. White bur-sage
(Ambrosia dumosa), creosote bush (Larrea tridentata), and Pima
rhatany (Krameria erecta) are relatively ubiquitous and
apparently unrelated to the presence of white-margined
beardtongue (Etyemezian et al. 2010).
Table 1. Habitat Associations for White-Margined Beardtongue
Land Cover
Habitat
Type
Designation
Mojave Desert Primary habitat
scrub, desert
dunes
Habitat
Parameters
1,398 to 3,494
feet elevation
Supporting
Information
Jepson Flora
Project 2011;
CDFG 2012a;
Etyemezian et
al. 2010
Reproduction
As a short-lived perennial with a large, deep root system, white-margined
beardtongue appears to reproduce primarily through production and
dispersal of seed (Etyemezian et al. 2010). Flowers emerge between
March and May (Jepson Flora Project 2011); peak flowering appears to
occur in April of most years (Etyemezian et al. 2010).
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White-Margined Beardtongue (Penstemon albomarginatus)
Like many Mojave Desert perennial plants, white-margined
beardtongue reproductive events are rare and episodic and may
require a combination of successive wet years that favor seed
production, seed germination, and seedling growth (Etyemezian et al.
2010). Andre (2010) notes that this species maintains a substantial soil
seed bank and survives underground as a subterranean heterotrophy
(root/caudex) during dry years (Andre 2010). Even during average
years of precipitation, a large percentage of the seed bank will not
germinate and many living plants remain dormant underground. Only a
subset of plants will put on above-ground growth, and an even fewer
number flower and set seed. Seed banks can persist in the soil for many
decades before germinating (Andre 2010).
Andre (2010) also has observed and documented frequent localized
extinctions of cohorts with rapid establishment of plants in previously
unoccupied areas. He concludes that plants at the California occurrence
behave like biennials or short-lived perennials, relying upon the
maintenance of a viable seed bank, and over time exhibit a shifting
distribution within the eolian sands where they occur (Andre 2010).
Etyemezian et al. (2010) observed very limited seed production and
dispersal of white-margined beardtongue at study sites in Nevada
during the drought years of 2008–2009. They attributed the lack of
reproductive success to drought and insect herbivory at two sites, but
did observe seed dispersal at one site in 2009. Seed dispersal
distances ranged from 1 to 15 centimeters (0.4 to 6 inches) at this site.
MacKay (2006) noted that white-margined beardtongue is present in
some washes but absent in other drainages nearby, and suggests that
might be due to both limited seed dispersal distances and the lack of
suitable stabilized deep sand in those other drainages (MacKay 2006).
She suggests that the small seeds could be scattered short distances
by ants or rodents, or may get transported by water in very wet years.
The tendency for plants to occur in scattered groups of up to 20
individuals, and the fact that young cuttings produce adventitious
roots in experiments (Scogin 1989, as cited in MacKay 2006), suggest
that vegetative reproduction may occur in this species in its natural
habitat, even though attempts to propagate from cuttings at the
garden failed (Scogin 1989, as cited in MacKay 2006).
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White-Margined Beardtongue (Penstemon albomarginatus)
Ecological Relationships
The success of white-margined beardtongue is dependent upon a
variety of interactions with pollinators and other nearby plant
species, as well as a variety of ecological processes. The showy flowers
are visited by several insects, including small carabid beetles, large
flies, and vespid wasps with orange abdomens. Pollen was observed
on upper-body surfaces of the vespids, making them the most likely
pollinator of white-margined beardtongue (Scogin 1989, as cited in
MacKay 2006).
White-margined beardtongue establishment is much more likely in
canopy inter‐spaces than under plant canopies, but Etyemezian et al.
(2010) could not determine whether competition with other
perennial species or other micro‐environmental factors were
responsible for this phenomenon (Etyemezian et al. 2010). For the
few individuals they noticed growing in under canopy locations, the
overstory species was equally likely to be white bur-sage or big
galleta grass (only in Clark County), but never creosote bush.
Etyemezian et al. (2010) studied eolian processes of sediment
transport within white-margined beardtongue habitat areas. They
conclude that it is unlikely that present‐day eolian sand transport
processes have any appreciable effect on habitat areas because the
eolian deposits in the sites were formed over geological time scales
and study measurements of sand transport indicated that present‐day
rates for eolian sediment transport are very slow to create new
deposits. However, they conclude that fluvial processes and sediment
transport via dry wash channels is the dominant present-day
geomorphic process at white-margined beardtongue sites in Nevada
(Etyemezian et al. 2010)
Population Status and Trends
Global: G2, Imperiled (CDFG 2012b)
State: S1, Critically Imperiled (CDFG 2012b)
White-margined beardtongue is classified as a 1B.1 rare plant species
by the California Rare Plant Ranking system. Species with the 1B rank
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White-Margined Beardtongue (Penstemon albomarginatus)
are rare, threatened, or endangered in California and elsewhere. The
0.1 threat rank indicates that this species is seriously threatened
(over 80% of occurrences are threatened or have a high degree and
immediacy of threat) in California.
Abundance estimates of white-margined beardtongue are heavily
dependent upon rainfall factors, and are difficult to assess due to the
large number of individuals that survive underground during dry
years (Andre 2010).
One of the largest occurrences of white-margined beardtongue in
California is a large, X-shaped occurrence that runs approximately 4
miles along a wash and 2 miles along a spreading basin. In 1989, 450
plants seen were seen at this site, which was damaged by military
activities that same year. In 2008, botanists observed 42 colonies of
white-margined beardtongue at this location (CDFG 2012a). Eight
plants were observed at the occurrence south of the Sleeping Beauty
lava flows in 1989. There are no population estimates for the
occurrences from 1935 to 1940. More recent occurrences (2008–
2010) generally do not provide population estimates to the CNDDB
(CDFG 2012a). Where population numbers are provided, they are
typically from 1 to 17 individuals (CDFG 2012a).
In Nevada, Etyemezian et al. (2010) re-surveyed 12 white-margined
beardtongue populations in 2008–2009 that were documented during
1997–1998 by F.J. Smith. These surveys resulted in population
estimates of 125,825 plants in Clark County and 78,954 plants in Nye
County. These estimates are almost five times greater than the earlier
estimates of 25,964 for Clark County and two times greater than the
42,200 plants estimated for Nye County, both during 1997–1998.
Surveys in 2008–2009 also were conducted in years of below-average
rainfall, so the actual size of white-margined beardtongue in Nevada
could be even greater than these estimates (Etyemezian et al. 2010).
Threats and Environmental Stressors
All of the white-margined beardtongue occurrences in California are
located within or adjacent to BLM verified solar and wind project
applications, the BLM Pisgah Solar Energy Zone, or approved solar
projects. In addition, they are located near possible military base
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White-Margined Beardtongue (Penstemon albomarginatus)
expansion lands, including Fort Irwin Army Base and Twentynine
Palms Marine Corps Air Ground Combat Center. According to the Land
Acquisition/Airspace Establishment Study Draft Environmental
Impact Statement (EIS), white-margined beardtongue is located in the
Lavic Lake Training Area, but it was not observed or discussed as
potentially occurring in the expansion areas to the west, south, and
east of the existing combat center (Department of the Navy 2011).
However, the EIS also reports potential habitat (i.e., creosote bush
scrub and/or desert dunes) for white-margined beardtongue in all
three expansion areas, so there is likely some risk to this species that
would result from these expansion plans.
This species is also potentially threatened by the presence of
Interstate 40 and numerous utility access roads that facilitate
movement of people and off-highway vehicles to the occupied habitat
areas. MacKay (2006) notes that repeated destruction of aboveground plants may use up nutrient stores within the long taproot of
the plant and result in declines of this species. Large, organized offroad races also create massive dust clouds and are held in areas
adjacent to white-margined beardtongue habitat areas in Nevada. The
dust has been seen rising hundreds of feet into the air (Mangrich,
pers. obs. 2009), and poses a potential threat to the Nevada
population’s pollinators, as well as the plant’s photosynthetic capacity
(Mangrich, pers. obs. 2009). Although there are no known organized
off-road races held near occupied habitat within the Plan Area, offhighway vehicle activity in the Plan Area could pose similar, albeit
somewhat less severe, threats.
Other threats include the presence of power lines and pipelines that
bring human disturbance into areas of occupied habitat (MacKay
2006). Military activities (e.g., camping) have also been observed in
the vicinity of occupied habitat areas, which could increase trampling
damage to the species (MacKay 2006).
Although white-margined beardtongue is a showy plant, it does not
appear that there is a threat resulting from horticultural efforts because
it doesn’t propagate well from cuttings, and transplantation efforts
have been unsuccessful (Scogin 1989, as cited in MacKay 2006).
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White-Margined Beardtongue (Penstemon albomarginatus)
Conservation and Management Activities
All of the California occurrences of white-margined beardtongue are
within the West Mojave Plan area (MacKay 2006), and as such, would
be subject to conservation and management activities associated with
that plan. These activities include the establishment of a habitat
conservation area, although it is unknown if that area encompasses
known occurrences of white-margined beardtongue, and plant
conservation strategies and an acquisition program to acquire and
enhance the protection of private lands within the habitat
conservation area (BLM 2005).
The BLM manages for sensitive plant species occurring on land it
administers, including on lands where white-margined beardtongue
have been documented. Management priorities are consistent with
the BLM’s principles of multiple use and include, but are not limited
to: developing and implementing range-wide and/or site-specific
management plans for sensitive plant species that include specific
habitat and population management objectives designed for recovery;
ensuring that BLM activities affecting the habitat of sensitive plant
species are carried out in a manner consistent with the objectives for
managing those species; and monitoring populations and habitats of
candidate plant species to determine whether management objectives
are being met (BLM 2003).
Data Characterization
White-margined beardtongue habitat requirements and general
reproductive observations (including seed-setting events, seed
predation, and plant recruitment; longevity; and mortality in relation
to precipitation) have been documented recently, most notably by
Etyemezian et al. (2010). However, this study focused on populations
in Nevada, not California. In addition, these studies were conducted
over 2 years; the study authors suggest longer-term monitoring of
these populations. They also recommend that a genetic analysis of
existing populations be conducted to better understand the impact of
the reproductive isolation of the Nevada, California, and Arizona
populations and to assess the overall genetic diversity within the
species (Etyemezian et al. 2010).
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White-Margined Beardtongue (Penstemon albomarginatus)
There are still data gaps in overall population trends due to a poor
understanding of the species’ seed dispersal and recruitment and
pollination. Researchers have speculated about pollinator
relationships (MacKay 2006), but no peer-reviewed literature on the
subject has been published. In addition, no studies have examined
seed viability, longevity in the soil, or how long plants can survive
dormancy. In addition, the requirements for seed germination and
establishment of new plants in the California population are unknown
(Etyemezian et al. 2010). MacKay (2006) also notes the need for
additional propagation studies to determine if seedlings, cuttings, or
transplanted plants could be used for mitigation efforts.
Management and Monitoring Considerations
Species protection activities should focus on CNDDB occurrences
known to occur in eastern San Bernardino County (CDFG 2012a), as
well as modeled habitat. The long-term viability of populations may
also rely on the protection of habitat corridors between these
populations. Because so little is known about the abundance and
distribution of white-margined beardtongue in California, and
because of their ability to survive underground for long periods of
time, focused surveys for this species should be conducted within
appropriate habitat in high-rainfall years in the Plan Area.
Due to the large, deep root system of white-margined beardtongue,
transplanting individuals from threatened populations to suitable
sites will not likely be a practical mitigation tool. Possibly, seed can be
used to establish new populations at sites that would be suitable
(Etyemezian et al. 2010).
Predicted Species Distribution in Plan Area
There are 426,989 acres of modeled suitable habitat for whitemargined beardtongue in the Plan Area. Modeled suitable habitat
occurs in the Bullion Mountains-Bristol Lake ecoregion subsection
from 1,300 to 3,500 feet in elevation. Modeled suitable habitat
includes scrub and wash vegetation communities, as well as desert
dunes and sand flats and desert playas. Appendix C includes specific
model parameters and a figure showing the modeled suitable habitat
in the Plan Area.
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White-Margined Beardtongue (Penstemon albomarginatus)
Literature Cited
Anderson, J.L. 1999. “The White-Margined Penstemon (Penstemon
albomarginatus Jones), a Rare Mohave Desert Species, and the
Hualapai Mountains Land Exchange in Mohave County,
Arizona.” Phoenix, Arizona: U.S. Bureau of Land Management.
Accessed November 20, 2011. http://www.fs.fed.us/rm/pubs/
rmrs_p023/rmrs_p023_027_037.pdf.
Andre, J. 2010. “Rebuttal Testimony in the Matter of Docket No. 08AFC-13 the Application for Certification for the Calico Solar
Project. Submitted to the State of California Energy Resources
Conservation and Development Commission.” July 29, 2010.
BLM (Bureau of Land Management). 2003. “Special Status Plant
Management.” BLM Manual Supplement 6840.06. Last revised
January 3, 2003. Accessed November 21, 2011.
http://www.blm.gov/pgdata/etc/medialib//blm/ca/pdf/
pdfs/pa_pdfs/biology_pdfs.Par.428edb73.File.pdf/
6840.06-supplement.pdf.
BLM. 2005. “Chapter Five Statutory Sections.” Final Environmental
Impact Report and Statement for the West Mojave Plan: A
Habitat Conservation Plan and California Desert Conservation
Area Plan Amendment Vol 1. Accessed December 22, 2011.
http://www.blm.gov/ca/pdfs/cdd_pdfs/wemo_pdfs/plan/we
mo/Vol-1-Chapter1_Bookmarks.pdf.
CDFG (California Department of Fish and Game). 2012a. “Penstemon
albomarginatus.” Element Occurrence Query. California
Natural Diversity Database (CNDDB). RareFind, Version 4.0
(Commercial Subscription). Sacramento, California: CDFG,
Biogeographic Data Branch. Accessed February 2012.
http://www.dfg.ca.gov/biogeodata/cnddb/ mapsanddata.asp.
CDFG. 2012b. Special Vascular Plants, Bryophytes, and Lichens List.
California Natural Diversity Database (CNDDB). January 2012.
Accessed March 2012. http://www.dfg.ca.gov/biogeodata/
cnddb/plants_and_animals.asp.
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White-Margined Beardtongue (Penstemon albomarginatus)
CNPS (California Native Plant Society). 2011. “Penstemon
albomarginatus.” Inventory of Rare and Endangered Plants,
Online ed. Version 8-01a. Sacramento, California: CNPS.
Accessed November 21, 2011. http://www.cnps.org/inventory.
Department of the Navy. 2011. Draft Environmental Impact Statement
Land Acquisition and Airspace Establishment to Support LargeScale Marine Air Ground Task Force Live Fire and Maneuver
Training. Marine Corps Air Ground Combat Center Twentynine
Palms, California. February 2011.
Etyemezian, V., J. King, S. Zitzer, G. Nikolich, J. Gillies, and J. Mason.
2010. Sediment Transport to White‐Margined Penstemon
Habitat (Penstemon albomarginatus). 2005‐NSHE‐502A‐P.
Prepared for Department of Air Quality and Environmental
Management Desert Conservation Program, Clark County,
Nevada. March 29, 2010.
Jepson Flora Project. 2011. “Penstemon albomarginatus.” M.
Wetherwax and N.H. Holmgren. Jepson eFlora [v. 1.0]. Berkeley,
California: University of California. Accessed December 8,
2011. Accessed November 20, 2011.
http://ucjeps.berkeley.edu/interchange/I_treat_indexes.html.
MacKay, P.J. 2006. “White-Margined Beardtongue.” West Mojave Plan
Species Accounts. U.S. Department of the Interior, Bureau of
Land Management. January 2006. Accessed November 2011.
http://www.blm.gov/ca/pdfs/cdd_pdfs/whitemarg1.PDF.
Mangrich, M. 2009. Personal observation of an off-road vehicle race
near Primm, Nevada, in April 2009 in areas where whitemargined beardtongue was documented the day before.
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