DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Kern Buckwheat
(Eriogonum kennedyi var. pinicola)
Legal Status
State: S1.11
California Rare Plant Rank: 1B.12
Federal: Bureau of Land Management Sensitive
Critical Habitat: N/A
Recovery Planning: N/A
Taxonomy
Kern buckwheat (Eriogonum kennedyi var. pinicola) is a perennial
herb in the buckwheat family (Polygonaceae) in the subgenus Eucycla
(CNPS 2011; Reveal 2003). The species, E. kennedyi, was described in
1877. The variety E. k. var. pinicola was first described by J.L. Reveal in
the Supplement to A California Flora (Reveal, cited in Munz 1968, p.
68). Kern buckwheat is also known by other common names,
including Sweet Ridge wild buckwheat (Reveal 2003) and Cache Peak
buckwheat (NatureServe 2011). Kern buckwheat stands
approximately 0.5 to 1.3 decimeters (2.0 to 5.1 inches) in height
(Jepson Flora Project 2011). A full physical description of the species
can be found in the Jepson eFlora (Jepson Flora Project 2011).
Distribution
General
Kern buckwheat is endemic to Kern County, California and known
from only three occurrences in the Sweet Ridge area of the
southeastern Sierra Nevada Foothills in southeastern Kern County
(Figure SP-P14; CNPS 2011; CDFG 2012a; Jepson Flora Project 2011).
All the occurrences recorded in the California Natural Diversity
Database (CNDDB) are in the Plan Area (CDFG 2012a).
1
2
S1: Critically imperiled; X.1: Critically imperiled.
1B: Rare, threatened, or endangered in California and elsewhere. X.1: Seriously threatened in California.
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Distribution and Occurrences within the Plan Area
Historical
All three CNDDB occurrences have been seen recently (i.e., since
1990) and are discussed below.
Recent
Two occurrences recorded in the CNDDB are located in the Ridgecrest
Recreation Area (RA), managed by the Bureau of Land Management
(BLM) (CDFG 2012a). The first, the type locality, occurs along trails on
Sweet Ridge 2 miles south-southeast of Cache Peak and consists of three
colonies. A 2010 collection was made at this type locality occurrence
(CCH 2011). The second occurrence in the Ridgecrest RA, is
approximately 1 mile west of Middle Knob. The third CNDDB occurrence
is on the west slope of Sweet Ridge, about 1.5 miles south of Cache Peak
and is located on private land owned by a wind energy development
company (CDFG 2012a).
Natural History
Habitat Requirements
Kern buckwheat is found in poorly draining depressions in white
bentonite clay soils that are derived from volcanic ash (Sanders and
Greene 2006). The depressions have pebbles, gravel, and rock cemented
into the soil surface that form exposed open flats located on ridge tops
and saddles between knolls (Sanders and Greene 2006).
This species occurs in chaparral and pinyon and juniper woodland
(CDFG 2012a, CNPS 2011). Associated species include California
sagebrush (Artemisia californica), Great Basin sagebrush (Artemisia
tridentata), adobe yampah (Perideridia pringlei), fivetooth spineflower
(Chorizanthe watsonii), and old fallen Jeffrey pines (Pinus jeffreyi)
(CDFG 2012a; CCH 2011). While CNPS (2011) reports an elevation
range of 1,340 to 1,950 meters (4,396 to 6,397 feet), the three
occurrences range from 5,400 to 6,000 feet (CDFG 2012a). Table 1 lists
primary habitat associations and parameters for Kern buckwheat.
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Table 1. Habitat Associations for Kern Buckwheat
Land Cover Type
Chaparral,
pinyon and
juniper
woodland,
pebble plains
Habitat
Designation
Primary
Habitat
Parameters
White bentonite
clay soils, 1,340
to 1,950 meters
(4,396 to 6,397
feet) elevation
Supporting
Information
Sanders and
Greene 2006; CNPS
2011
Reproduction
Kern buckwheat blooms from May to June (CNPS 2011, Jepson Flora
Project 2011). The fruit ripens and is dispersed around July. Sexual
reproduction in Kern buckwheat is probably both selfing and
outcrossing (NatureServe 2011) considering the federally listed
variety E. k. var. austromontanum produces seeds by self-pollinating
and insect-mediated outcrossing (71 FR 67712–67754).
Eriogonum species generally attract small generalist pollinators.
Visitors, and potential pollinators, of the species Eriogonum kennedyi
are small wasps, flies, bees, butterflies, and ants (O’Brien 1980). A
small, silvery-white, iridescent butterfly has been observed
pollinating this variety (Hare, pers. obs., cited in Sanders and Greene
2006). Kern buckwheat flowers change to red when pollinated
suggesting that bees are important pollinators.
Though seed dispersal for this taxon has not been studied, birds may
play a role in the dispersal of all Eriogonum seeds. Although there is
little information available, wind, rain and streams may also act as
dispersal agents (Sanders and Greene 2006).
Ecological Relationships
Kern buckwheat appears to share many general ecological
characteristics with other varieties of E. kennedyi. It occurs in open
areas and prefers full sunlight, appearing to be intolerant of extensive
shading. Although not well adapted to competing for light, it is very
competitive on sites where tall and fast-growing species are excluded
by moisture deficiencies, wind, and cold (Walter 1973, cited in Sanders
and Greene 2006). Its compact cushion-like habit probably helps to
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
reduce moisture loss (Walter 1973, cited in Sanders and Greene 2006).
Therefore, this variety appears to favor sites where moisture stress is
combined with high insulation (Sanders and Greene 2006).
Moisture rather than light is probably a controlling factor for Kern
buckwheat. The foliage is densely covered with tomentum (wool) that
substantially reduces the amount of light that strikes the leaf tissue.
Although pubescence may affect photosynthesis, it also forms a layer
of dead air at the leaf surface, which can reduce water loss from wind
(Johnson 1975, cited in Sanders and Greene 2006).
Population Status and Trends
Global: G4, Apparently Secure (NatureServe 2011, conservation
status last updated in 1997)
State: S1.1, Imperiled (CDFG 2012b)
Kern buckwheat is known from only three occurrences, one consisting
of three separate colonies, in the Sweet Ridge area (CPNS 2011; CDFG
2012a). Two of the three colonies at the type locality each consisted of
more than 100 plants in 1992, 1993, and 1994. The remaining colony
included over 100 plants in 1994 (CDFG 2012a). A collection in this area
reported the population as abundant in 2010 (CCH 2011). The
occurrence west of Middle Knob, was considered locally common in
1966 and included over 100 plants in 1993, 1995, and 1996. The
occurrence on the west slope of Sweet Ridge included over 100 plants in
1994 (CDFG 2012a). There are also 1,000 individuals mapped at one
site in the North Sky River project area that were recorded recently
(Kern County 2011).
At one time up to six occurrences were identified as Kern buckwheat
(Sanders and Greene 2006), but some were misidentified and only
three have been verified as Kern buckwheat (CDFG 2012a). There
were an estimated 400 plants based on observations in the early
1990s, but surveys in 1998 estimated the total population at
approximately 10,000 individuals in four populations (Rutherford
1998, cited in Sanders and Greene 2006). It is unclear how these
populations relate to the three currently known CNDDB occurrences.
During these surveys it was noted that the populations contained a
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Species Accounts
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DRAFT
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PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
range of age classes and appeared reproductively healthy (Rutherford
1998, cited in Sanders and Greene 2006).
Kern buckwheat has been searched for extensively on Edwards Air
Force Base since 1991 but has not been found there, and there is no
suitable habitat. The Tehachapi So., Monolith, Mojave, Mojave NE,
Cache Peak, Tehachapi NE, and portions of the Cross Mountain U.S.
Geological Survey (USGS) quadrangles have also been searched. In
addition, the Middle Knob/Pine Tree Canyon area has been searched
by a BLM botanist but no Kern buckwheat has been found
(NatureServe 2011). However, it is possible that additional
populations could exist on unexplored ridgetops in the area since
much of the occupied area is rugged and poorly explored (Sanders
and Greene 2006).
Threats and Environmental Stressors
Current threats to Kern buckwheat are wind energy development on
private land and vehicles (CNPS 2011). Off-highway vehicles have
already destroyed plants and habitat in one of the occurrences on
BLM land. The highly restricted distribution and small number of
remaining plants make this species vulnerable to stochastic extinction
(Sanders and Greene 2006).
Approximately half of the 1-acre population on private land on Sweet
Ridge was destroyed by the construction of wind energy facilities.
Suitable habitat and plants were destroyed with the construction of
access roads to newly subdivided lots and the construction of a ramp
to a proposed campsite along the Pacific Crest Trail. Illegal grading
has resulted in an erosion problem that threatens part of one
population (Hare 1995 and Rutherford 1998, cited in Sanders and
Greene 2006). Although cattle grazing is not known around the
populations now, the area has been grazed in the past (Sanders and
Greene 2006).
Based on observations, Kern buckwheat has been unable to recolonize
disturbed areas (Hare 1995, cited in Sanders and Greene 2006).
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Conservation and Management Activities
Two of the three known occurrences are located on BLM land within
the Ridgecrest RA (CDFG 2012a). The BLM manages for sensitive
plant species occurring on land they administer, including on lands
where kern buckwheat have been documented (BLM 2003). The
remaining occurrence is located on private land owned by a wind
energy development company; the presence of Kern buckwheat may
not have been considered when a power substation was relocated in
1989 (CDFG 2012a).
Kern buckwheat is also covered by the West Mojave Plan. The lan
proposes to avoid all occurrences on private lands and restore and
enhance habitat on public lands. Habitat on public lands would also be
managed with conservation measures including establishment of the
Middle Knob Conservation Area and Area of Critical of Environmental
Concern (ACEC), where avoidance of this species would be required
for any ground-disturbing projects; vehicle barriers along the main
access road where it adjoins occupied habitat; fencing on both sides of
the road near the Sweet Ridge population and restoring a vehicle
turnaround and parking area to avoid buckwheat habitat; and signage
at habitat along the Pacific Crest Trail. On private lands, the species
will be avoided for any private land ground-disturbing projects in the
proposed Middle Knob Conservation Area, and take for Kern
buckwheat would be limited to very small areas that may be impacted
by restoration activities (BLM 2005).
Data Characterization
Although extensive surveys have been conducted in the area, it is
possible that additional populations could exist on unexplored
ridgetops in the area since much of the occupied area is rugged and
poorly explored (Sanders and Greene 2006). Plant establishment,
growth, and survival has not been formally studied for this variety. In
addition, detailed studies of the ecophysiology of this species would
be beneficial (Sanders and Greene 2006).
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Management and Monitoring Considerations
A survey of all suitable habitat areas is needed to determine the
number, extent, and condition of populations. Private landowners
should be notified of the existence of this rare species and how to
prevent future disturbance. Soils in habitat for Kern buckwheat are
very fragile and easily disturbed and Kern buckwheat does not
recolonize disturbed ground. Therefore, restricting vehicle access to
roads and trails through the habitat, placing physical barriers along
roads, and closing jeep trails when the area is wet can reduce soil
disturbance. The BLM should erect signs along the Pacific Crest Trail
asking hikers to stay off sensitive open flat habitat (Sanders and
Greene 2006).
Another monitoring consideration would be the issue of identification
since past misidentifications been an issue with knowing the variety’s
true range and distribution. Kern buckwheat is quite similar to a few
varieties including Eriogonum kennedyi var. purpusii and Eriogonum
wrightii var. subscaposum. However, there are very good keys now
that should limit misidentification.
Predicted Species Distribution in Plan Area
There are 18,193 acres of modeled suitable habitat for Kern
buckwheat in the Plan Area. Modeled suitable habitat occurs in the
Tehachapi-Piute Mountains from 4,300 to 6,400 feet in elevation.
Modeled suitable habitat includes chaparral and pinyon-juniper
woodland vegetation communities with clay soils. Appendix C
includes specific model parameters and a figure showing the
modeled suitable habitat in the Plan Area.
Literature Cited
71 FR 67712–67754. Proposed rule: “Endangered and Threatened
Wildlife and Plants; Designation of Critical Habitat for Arenaria
ursina (Bear Valley sandwort), Castilleja cinerea (ash-gray
Indian paintbrush), and Eriogonum kennedyi var.
austromontanum (southern mountain wild-buckwheat).”
November 22, 2006.
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Species Accounts
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DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
BLM (Bureau of Land Management). 2003. “Special Status Plant
Management”. BLM-California 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/6840.06supplement.pdf.
BLM. 2005. “Chapter Two, Alternatives”. 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.
CCH (Consortium of California Herbaria). 2011. Accession results for
“Eriogonum kennedyi var. pinicola.” Accessed December 28,
2011. http://ucjeps.berkeley.edu/consortium.
CDFG (California Department of Fish and Game). 2012a. “Eriogonum
kennedyi var. pinicola.” 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.
CNDDB. January 2012. Accessed February 2012.
http://www.dfg.ca.gov/biogeodata/cnddb/
plants_and_animals.asp.
CNPS (California Native Plant Society). 2011. “Eriogonum kennedyi var.
pinicola.” Inventory of Rare and Endangered Plants. Online ed.,
Version 8-01a. Sacramento, California: CNPS. Accessed
November 2011. http://www.cnps.org/inventory.
Jepson Flora Project . 2011. “Eriogonum kennedyi var. pinicola.” J.L.
Reveal, ed. Jepson eFlora [v. 1.0]. Berkeley, California:
University of California. Accessed December 5, 2011.
http://ucjeps.berkeley.edu/IJM.html.
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
Kern Buckwheat (Eriogonum kennedyi var. pinicola)
Kern County, Planning and Community Development Department.
2011. “Section 4.4 Biological Resources” North Sky River Wind
Energy Project and Jawbone Wind Energy Project Environmental
Impact Report. Draft. SCH no. 2010121042. Bakersfield,
California. May 2011. Accessed December 30, 2011.
http://www.co.kern.ca.us/planning/pdfs/eirs/northsky_jawb
one/DEIR/4.4-BioResources.pdf.
Munz, P.A. 1968. Supplement to A California Flora. Berkeley, California:
University of California.
O’Brien, M.H. 1980. “The Pollination Biology of a Pavement Plain:
Pollinator Visitation Patterns.” Oecologia 47:213–218.
NatureServe. 2011. “Eriogonum kennedyi var. pinicola.” NatureServe
Explorer: An Online Encyclopedia of Life. Version 7.1. Arlington,
Virginia: NatureServe. Last updated July 2011. Accessed
November 2011. http://www.natureserve.org/explorer.
Reveal, J.L. 2003. “Taxonomic Eriogonoideae (Polygonaceae) of North
America north of Mexico.” University of Maryland. Last
updated December 13, 2003. Accessed December 29, 2011.
http://www.plantsystematics.org/reveal/pbio/eriog/
erioeucy/kennedyi.html.
Sanders, A.C., and J.A. Greene. 2006. “Kern Buckwheat.” West Mojave
Plan Species Accounts. U.S. Department of the Interior, Bureau
of Land Management. January 2006. Accessed November 22,
2011. http://www.dmg.gov/documents/
WMP_Species_Accounts/Species%20Accounts-Plants.pdf.
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March 2012