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Charlotte’s Phacelia (Phacelia nashiana)
Charlotte’s Phacelia
(Phacelia nashiana)
Legal Status
State: S31
California Rare Plant Rank: 1B.22
Federal: Bureau of Land Management (BLM) Sensitive
Critical Habitat: N/A
Recovery Planning: N/A
Taxonomy
Charlotte’s phacelia (Phacelia nashiana) is an annual herb in the
borage family (Boraginaceae) that is endemic to California. Phacelia
was formerly included in the waterleaf family Hydrophyllaceae
(Wilken et al. 2012) but has been recently moved to the Boraginaceae
(Jepson Flora Project 2011, Phacelia Group 3).
The species was originally described by Jepson in 1943 (as cited in
White 2006) from a collection near Ninemile Canyon in Inyo County.
The wide, crenate to weakly lobed leaves; the annual habitat and
many-seeded fruits (40–80); and bright corolla distinguish Charlotte’s
phacelia from other phacelias. White (2006) notes that P. parryi, P.
viscida, P. minor, and P. longiceps are similar species, but adds that
these species have little geographic overlap with Charlotte’s phacelia.
Charlotte’s phacelia is typically 3 to 18 centimeters (1.2 to 7.1 inches)
tall. A full description of the species can be found in the Jepson eFlora
(Jepson Flora Project 2011).
Chester (2008) examined and compared isotype specimens of P.
nashiana, P. campanularia ssp. campanularia, and P.c. ssp. vasiformis
and concluded that the type specimens for P. nashiana and P.
campanularia ssp. campanularia were virtually identical. He also
compared data from collections of ssp. campanularia made at Deep
Canyon and Whitewater in Riverside County, and of P. nashiana at
1
2
S3: Vulnerable.
1B: Rare, threatened, or endangered in California and elsewhere; X.2: Fairly threatened in California.
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Charlotte’s Phacelia (Phacelia nashiana)
Borrego Palm Canyon in San Diego County, and concluded that the
ssp. campanularia collections from Whitewater and Deep Canyon
were most closely aligned with the taxon P. nashiana and that the
population in Borrego Palm Canyon was P. nashiana and not P.
campanularia ssp. campanularia. However, the Jepson Flora Project
(2011) continues to recognize P. nashiana and P. campanularia ssp.
campanularia as separate taxa.
The Borrego Palm Canyon collections made by Chester, Madore, and
Charters in 2005 were later annotated and confirmed as Charlotte’s
phacelia by John Rebman in 2010 ( Consortium of California
Herbaria 2011).
Distribution
General
Based on the evident taxonomic confusion noted above, the
distribution and extent of Charlotte’s phacelia is less clear, and
occurrences of Charlotte’s phacelia could be more widespread than
current records reflect. The records and distribution information in
this report address the known locations of populations that have been
previously identified as Charlotte’s phacelia, including the isolated
population in San Diego County.
Charlotte’s phacelia is an endemic species that occurs in the desertfacing foothills of the Sierra Nevada and the adjacent El Paso
Mountains, in Tulare, Inyo, and Kern counties (CDFG 2012a). Although
not included in the CNPS Inventory (CNPS 2011) or CNDDB (CDFG
2012a), Charlotte’s phacelia also occurs in Anza-Borrego State Park in
San Diego County (Consortium of California Herbaria 2011). It ranges
from about 1,600 to 7,200 feet in elevation (CDFG 2012a; Consortium
of California Herbaria 2011). In addition to the Borrego population,
species occurrences include the foothills above Fremont Valley, Red
Rock Canyon State Park, the east-facing canyons above Indian Wells
Valley, the southern and northeastern slopes and canyons of the El
Paso Mountains, the El Paso Mountains, the Volcano Peak area within
the China Lake Naval Air Weapons Center, and around Lake Isabella
(BLM 2005; CDFG 2012a).
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Charlotte’s Phacelia (Phacelia nashiana)
The historical distribution of the species in California included
locations near Red Rock Canyon, Indian Wells, along the Pacific Coast
Trail and the eastern slopes of the Sierra Nevada, and at the base of
the El Paso Mountains. With the exception of the Borrego population
in the washes along Palm Canyon, most of Charlotte’s phacelia’s
recorded range is east of the Sierra Nevada crest and is within the
West Mojave Planning Area. Many populations are situated near roads
or trails in the lower canyons and washes, or are located within
natural areas, such as state parks and foothills. Numerous locations
along access roads within the Los Angeles Aqueduct have also been
documented, and more unrecorded populations are assumed to occur
on inaccessible mountain slopes above the foothills and within the
China Lake Naval Air Weapons Center area (White 2006).
Within Kern, Inyo, Tulare, and San Diego counties, populations of
Charlotte’s phacelia occur in the following U.S. Geological Survey 7.5minute quadrangles: Mojave NE, Saltdale NW, Cantil, Saltdale SE,
Cinco, Owens Peak, Freeman Junction, Walker Pass, Cane Canyon,
Horse Canyon, Volcano Peak, Little Lake, Ninemile Canyon, Lamont
Peak, Haiwee Pass, Long Canyon, and Borrego Palm Canyon (CNPS
2011; CDFG 2012a). The majority of the records (54) are from Kern
County in the Owens Peak, Cantil, and Cinco quadrangles. The
occurrence along the Pacific Coast Trail in the Lamont Peak
quadrangle is the first record of the species in Tulare County.
Distribution and Occurrences within the Plan Area
Historical
There are a total of 67 occurrences of Charlotte’s phacelia in the
California Natural Diversity Database (CNDDB), but only 50 occur
within the Plan Area (CDFG 2012a). Of the occurrences within the
Plan Area, 20 are considered historic but are still presumed extant.
These primarily occur within the BLM’s Ridgecrest Recreation Area
with some occurrences within Red Rock Canyon State Park and
Sequoia National Forest, as well as other BLM and private land (Figure
SP-P8; CDFG 2012a). The remaining 30 occurrences within the Plan
Area have been recorded since 1990 and are discussed below.
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Charlotte’s Phacelia (Phacelia nashiana)
Recent
Of the 30 recent occurrences within the Plan Area, 23 occur on BLM
land. Of these, one may be under partial private ownership, and one is
designated an Area of Critical Environmental Concern (ACEC) by the
BLM. In addition, eight of these are within the Ridgecrest Recreation
Area. The remaining seven occurrences not on BLM land are within Red
Rock Canyon State Park under Department of Parks and Recreation
management (CDFG 2012a). Most records note an estimated size of a
few hundred plants, although one population of approximately 8,000
plants occurs south of Jawbone Canyon in the BLM-designated ACEC
(BLM 2005; CDFG 2012a; Figure SP-P8).
Natural History
Habitat Requirements
Charlotte’s phacelia is found in Joshua tree woodland, Mojavean
desert scrub, and pinyon-juniper woodland, usually on granitic soils
in sandy or rocky areas on steep slopes or flats (CNPS 2011; CDFG
2012a). At higher elevations, Charlotte’s phacelia occurs in open pinyon
woodland on gravelly sands and talus and is often associated with green
ephedra (Ephedra viridis) and single-leaf pinyon (Pinus monophylla)
(White 2006). CDFG (2012a) lists several records of occurrence between
4,000 and 6,000 feet on slopes of 40%, and substrates of loose gravels or
granitic soils. Several occurrences are on dynamic or recently disturbed
sites, and the species has potential to occur on road cuts, berms, and
other disturbed habitats, especially near washes (White 2006; CDFG
2012a). A few records also list metamorphic soils, and some populations
near Cudahy Camp in the Saltdale Quadrangle occur on volcanic tuff
(CDFG 2012a).
At lower elevations, the species is often found in canyons (e.g., Red
Rock, Jawbone, Iron, Pine Tree, and Mesquite canyons) and
occasionally on slopes adjacent to washes. General habitats include
Joshua tree woodland and Mojavean creosote scrubs, where
Charlotte’s phacelia is commonly associated with species such as
Joshua tree (Yucca brevifolia), creosote bush (Larrea tridentata),
Fremont indigobush (Psorothamnus fremontii), burrobush (Ambrosia
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Charlotte’s Phacelia (Phacelia nashiana)
dumosa), peach thorn (Lycium cooperi), and Bigelow’s tickseed
(Coreopsis bigelovii) (CDFG 2012a; White 2006) (Table 1).
Table 1. Habitat Associations for Charlotte’s Phacelia
Land Cover Type
Pinyon and juniper
woodland, Joshua
tree woodland,
Mojavean desert
scrub
Habitat
Designation
Habitat
Parameters
Primary habitat
Granitic soils,
coarse sandy and
rocky area, from
2,000 to 7,200
feet elevation
Supporting
Information
Jepson Flora
Project 2011;
CDFG 2012a
Reproduction
Flowering periods have been variously reported between March and
June and Charlotte’s phacelia can be found in flower by late March at
lower elevations (White 2006; Consortium of California Herbaria
2011). However, specimens collected by Chester, Kay, and Madore
from Borrego Palm Canyon were flowering in February (Consortium
of California Herbaria 2011).
Nothing is known about the reproductive biology of the species. Some
similar Phacelia species, such as Parry’s phacelia, are fire-adapted, but
it is unknown whether Charlotte’s phacelia has any similar adaptation
. The habitats occupied by Charlotte’s phacelia are frequently open
and sparse, and the elevation ranges are higher than other Phacelia
species, which could suggest that a similar, fire-adapted lineage is not
likely (White 2006). Pollination vectors and seed dispersal remain
unknown for the species.
Population data collected in a few known locations over time appear
to fluctuate widely (CDFG 2012a), and winter rainfall could be key in
both distribution and population size.
Ecological Relationships
Some population data are known for Charlotte’s phacelia, but they do
not provide much information regarding the populations over time.
The BLM West Mojave Plan recommends that further surveys be
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Charlotte’s Phacelia (Phacelia nashiana)
made to record fluctuations in population estimates at known
locations, particularly with respect to the potential effects of grazing.
Population Status and Trends
Global: G3, Vulnerable (CDFG 2012b)
State: S3, Vulnerable (CDFG 2012b)
Populations of Charlotte’s phacelia were censused in 1986 at 28
locations by M. Henry, and while many of the locations had hundreds
of plants, some locations had only a few plants (CDFG 2012a; White
2006). Sites that have been censused several years since seem to
fluctuate considerably from year to year. White (2006) concludes that
Charlotte’s phacelia is likely secure over most of its range, as the
numbers of plants in many known locations remain relatively high,
and other populations are assumed to be less accessible to the threats
of grazing and trampling. However, information regarding the extent
of the species’ distribution, particularly outside of Kern and Inyo
counties, remains scarce and unknown, and isolated populations
could be at risk.
Threats and Environmental Stressors
Impacts on Charlotte’s phacelia from grazing and off-road vehicles are
the most frequently noted threats in the CNDDB records (CDFG
2012a). Trampling and collecting by hikers were also listed as threats
to populations that occur along trails and within parks and
recreational areas. Mining activities were noted as threats in a few
locations, and activities and/or expansion of facilities at China Lake
Naval Air Weapons Center could also pose a threat to populations
near Volcano Peak outside of the Plan Area and Indian Wells within
the Plan Area.
Conservation and Management Activities
Charlotte’s phacelia occurs on lands managed by the BLM and is a
covered plant species under the West Mojave Plan. Most of the known
sites are either under federal or state protection, and occur within
ACECs, wilderness areas, and Red Rock Canyon State Park (BLM 2005).
Conservation measures for the species include designation of a network
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Charlotte’s Phacelia (Phacelia nashiana)
of travel routes through the El Paso Mountains that would minimize
parallel routes, hill climbs, and straying from established paths.
A total of 30 ACECs were established by the BLM within the western
Mojave Desert as part of the 1980 California Desert Conservation Area
Plan, and specific management plans have been prepared for most of
these. Two areas established as ACECs support populations of
Charlotte’s phacelia (BLM 1999, 2005).
The Sand Canyon ACEC is a 2,609-acre area in a canyon on the
eastern slope of the Sierra Nevada that was established in 1989 to
protect riparian habitat and wildlife. It is one of the most diverse
areas in the West Mojave for species of small mammals and also
supports two populations of Charlotte’s phacelia, with over 1,000
plants (BLM 2005).
The Short Canyon ACEC was established in 1988 to protect the
unusual vegetation and diverse flora that occurs in a 754-acre area
that lies within the Owens Peak Wilderness. The Short Canyon ACEC is
known to support occurrences of Charlotte’s phacelia, as well as the
state-listed Mojave tarplant (Deinandra mohavensis). A management
plan was prepared in 1990 to exclude grazing through the
implementation of fencing and cattle guards (BLM 2005).
The current BLM West Mojave Plan provides management for
sensitive plant species that includes some site-specific management
plans and the monitoring of populations of candidate plant species. As
a covered species under the plan, the goal for Charlotte’s phacelia is to
maintain and enhance the existing occurrences and habitat. Incidental
take is allowed on public and private lands outside the ACECs,
wilderness areas, and El Paso Mountains, but is not to exceed 50 acres
(BLM 2005).
Data Characterization
Charlotte’s phacelia has been surveyed relatively extensively in Kern
County and some portions of Inyo County, but collection data are
scarce for areas south (San Diego County) of the known range, and
only one record occurs for Tulare County. Many previously recorded
populations have not been revisited and there is a need for further
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Charlotte’s Phacelia (Phacelia nashiana)
surveys to confirm population estimates of the extant populations and
to study the ecological parameters affecting distribution of the
species, particularly fluctuations in population numbers over time and
aspects of reproduction, dispersal, and hydrology. As noted above,
taxonomic confusion is evident with respect to populations of P.
nashiana and P. campanularia ssp. campanularia, and resolution of the
taxonomy could change the range and distribution of the taxa.
Management and Monitoring Considerations
White (2006) recommends that locations supporting substantial
Charlotte’s phacelia populations be assessed to document the
fluctuations in population numbers in response to climatic
conditions and grazing.
The West Mojave Plan recommends that any management actions
planned within the species’ range should consider potential effects on
Charlotte’s phacelia populations and habitat suitability. Management
and monitoring strategies that have been identified for Charlotte’s
phacelia concentrate on monitoring the populations in the two ACECs
and in Red Rock Canyon State Park, and monitoring the disturbance to
populations in the El Paso Mountains. The West Mojave Plan also
proposes a regional rangeland health assessment of the area in
eastern Sierra canyons within 2 years of plan approval. Adaptive
management goals include the use of fencing if monitoring reveals
damage from off-highway-vehicle use in the El Paso Mountains, and
the adjustment of grazing practices if the rangeland health assessment
does not meet requirements. Cattle grazing on the slopes of the
eastern Sierra Nevada Mountains would be restricted in known
habitat between April 1 and July 1 (BLM 2005).
Predicted Species Distribution in Plan Area
There are 872,531 acres of modeled suitable habitat for Charlotte’s
phacelia in the Plan Area. Modeled suitable habitat occurs in the
northwestern portion of the Plan Area from 2,000 to 7,200 feet in
elevation. Modeled suitable habitat includes selected woodland,
forest, and shrub communities, as well as North American warm
desert bedrock cliff and outcrop and Sierra Nevada cliff and canyon
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Charlotte’s Phacelia (Phacelia nashiana)
(see Figure SP-P8 in Appendix B). Appendix C includes specific
model parameters and a figure showing the modeled suitable habitat
in the Plan Area.
Appendix C provides a summary of the methodology used to model
DRECP Covered Species with Maxent. For Charlotte’s phacelia, 67
occurrence points were used to train the Maxent model and 22
occurrence points were used to test the model’s performance. Overall,
the Maxent model has excellent statistical support. The majority of
occurrence points appear to occur in a limited geographical area,
increasing the predictive power of the model. Based on a natural break
in the distribution of the probability of occurrence that Maxent
estimates, all 100-meter grid cells with greater than 0.207 probability
of occurrence were defined as Charlotte’s phacelia habitat.
The Maxent model predicts 243,499 acres of Charlotte’s phacelia
habitat, compared with 872,531 acres predicted by the expert model.
The Maxent model predicts Charlotte’s phacelia habitat in the West
Mojave with concentrated areas of habitat in the foothills of the
Tehachapi Mountains encompassing occurrence data. It also predicts
small patches in the West Mojave lacking occurrence data; the model
may need to be adjusted to exclude these patches. The expert model
also predicts habitat encompassing occurrence records similar to the
Maxent model, but covers a greater area around the occurrence data.
Literature Cited
BLM (Bureau of Land Management). 1999. “Current Management
Situation of Special Status Plants in the West Mojave Planning
Area” (Parish’s phacelia). BLM-California Manual Supplement
6840.06, p. 158. March 1999. Accessed November 30, 2011.
http://www.blm.gov/pgdata/etc/medialib//blm/ca/pdf/
pdfs/cdd_pdfs.Par.ae863836.File.pdf/pfp890295548.pdf.
BLM. 2005. Final Environmental Impact Report and Statement for the
West Mojave Plan. Volume 1, Chapters 2 and 3. Moreno Valley,
California: BLM. January 2005. Accessed November 2011.
http://www.blm.gov/ca/st/en/fo/cdd/wemo.html.
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Charlotte’s Phacelia (Phacelia nashiana)
CDFG (California Department of Fish and Game). 2012a. “Phacelia
nashiana.” 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.
Chester, T. 2008. “Phacelia nashiana = campanularia” (Comparison of
P. nashiana with P. campanularia ssp. campanularia). Last
revised March 5, 2008. http://tchester.org/plants/analysis/
phacelia/campanularia.html.
CNPS (California Native Plant Society). 2011. “Phacelia nashiana.”
Inventory of Rare and Endangered Plants. Online ed. Version 801a. Sacramento, California: CNPS. Accessed November 19,
2011. http://www.rareplants.cnps.org/detail/1111.html.
Consortium of California Herbaria. 2011. Accession results for
Phacelia nashiana. Accessed December 2, 2011.
http://ucjeps.berkeley.edu/consortium.Jepson Flora Project.
2011. “Phacelia nashiana.” R. Patterson, L.M. Garrison, and D.R.
Hansen. Jepson eFlora [v. 1.0]. Berkeley, California: University
of California. Accessed December 12, 2011.
http://ucjeps.berkeley.edu/IJM.html.
White, S.D. 2006. “Charlotte’s Phacelia.” West Mojave Plan Species
Accounts. U.S. Department of the Interior, Bureau of Land
Management. January 2006. Accessed December 12, 2011.
http://www.blm.gov/pgdata/etc/medialib//blm/ca/pdf/
pdfs/cdd_pdfs.Par.86ffa9bf.File.pdf/charlottes1.PDF.
Wilken, D.E., R.R. Halse, and R.W. Patterson. 2012. “Phacelia.” In The
Jepson Manual: Vascular Plants of California, edited by B.G.
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Charlotte’s Phacelia (Phacelia nashiana)
Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, and T.J. Rosatti.2nd
ed.. Berkeley, California: University of California Press.
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