DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
San Bernardino Mountains Dudleya
(Dudleya abramsii ssp. affinis)
Legal Status
State: S2.21
California Rare Plant Rank: 1B.22
Federal: U.S. Forest Service Sensitive
Critical Habitat: N/A
Recovery Planning: N/A
Taxonomy
San Bernardino Mountains dudleya (Dudleya abramsii ssp. affinis) is a
perennial herb in the stonecrop family (Crassulaceae) (CNPS 2011).
Dudleya abramsii ssp. affinis was published as a new subspecies by
K.M. Nakai (1987). Dudleya abramsii is a widespread species with six
subspecies currently recognized, five of which are very similar
(Jepson Flora Project 2011a).
There is some taxonomic uncertainty regarding the plants from
Cushenbury Canyon. These plants grow on limestone and differ from
most plants of San Bernardino Mountains dudleya in that they have
several to many branched caudex and smaller rosettes. They resemble
plants of D. a. ssp. calicola and D. a. ssp. abramsii. However, they also
differ from these other subspecies in having a more simple
inflorescence compared to D. a. ssp. calicola and having a different
rosette leaf shape compared to D. a. ssp. abramsii. Therefore, although
this population is intermediate between these three subspecies, Nakai
(1987) still considers it an aberrant form of D. a. ssp. affinis (Nakai
1987; Jepson Flora Project 2011b). This is unlikely to influence the
subspecies’ legal status because the taxonomic uncertainty appears to
be limited to one known population.
San Bernardino Mountains dudleya’s succulent leaves are in small
rosettes only 3 to 6 centimeters (1.2 to 2.4 inches) wide (Jepson Flora
1
2
S2: Imperiled; X.2: Imperiled.
1B: Rare, threatened, or endangered in California and elsewhere; X.2: Fairly threatened in California.
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Species Accounts
March 2012
DRAFT
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PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
Project 2011b). A full physical description of the species can be found
in the original description (Nakai (1987) and the Jepson eFlora
(Jepson Flora Project 2011b; Nakai 1987).
Distribution
General
San Bernardino Mountains dudleya is known only from a very small
area in the San Bernardino Mountains in southwest San Bernardino
County (Figure SP-P28; CNPS 2011). It occurs along the western edge
of the Plan Area. Only 2 of the 12 occurrences documented in the
California Natural Diversity Database (CNDDB) are within the Plan
Area, although there are eight additional occurrences within 5 miles
of the Plan Area (CDFG 2012a). All records from the Consortium of
California Herbaria (CCH) are outside of the Plan Area to the south or
west (CCH 2011).
Distribution and Occurrences within the Plan Area
Historical
Of the two occurrences of San Bernardino Mountains dudleya within
the Plan Area, one is based on a collection made in 1882 at
Cushenbury Springs in the Big Bear City U.S. Geological Survey (USGS)
quadrangle (Figure SP-P28; CDFG 2012a). This occurrence is on
private land owned by Mitsubishi Cement Corp. (formerly Kaiser
Cement Company) (CDFG 2012a; Deacon 2007).
Recent
The one recent occurrence of San Bernardino Mountains dudleya
reported in the Plan Area by the CNDDB occurs along the northeast slope
of White Mountain, approximately 1.6 miles east of North Peak, on the
north slope of the San Bernardino Mountains. Approximately 20 plants
were observed in 1996. Ownership of the land on which this occurrence
is located is unknown (CDFG 2012a).
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Species Accounts
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DRAFT
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PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
Natural History
Habitat Requirements
San Bernardino Mountains dudleya grows in pebble plain or
pavement habitat within pinyon and juniper woodland and upper
montane coniferous forest (CNPS 2011; CDFG 2012a). San Bernardino
Mountains dudleya occurs on granitic and quartzite substrates, rarely
on limestone (CNPS 2011; CDFG 2012a). The two occurrences within
the Plan Area do grow on limestone; the species commonly occurs on
rock outcrops (CDFG 2012a). Associated species include junipers
(Juniperus spp.), pines (Pinus spp.), mountain-mahogany (Cercocarpus
spp.), hedgehog cactus (Echinocereus spp.), Cushenbury milkvetch
(Astragalus albens), Parish’s daisy (Erigeron parishii), Cushenbury
buckwheat (Eriogonum ovalifolium ssp. vineum), and Cushenbury
oxytheca (Acanthoscyphus parishii var. goodmaniana). San Bernardino
Mountains dudleya ranges in elevation from 1,250 to 2,600 meters
(4,101 to 8,530 feet) according to CNPS (2011). Although the Jepson
eFlora (Jepson Flora Project 2011b) cites a much higher minimum
elevation of 1,800 meters (5,906 feet), CNDDB records state
elevations that are more similar to the range provided by CNPS
(2011): 4,200 to 8,500 feet (CDFG 2012a). Furthermore, the elevation
range of occurrences within the Plan Area is narrower and is within
the lower portion of the species’ overall elevation range, from 4,200 to
5,200 feet (CDFG 2012a).
Table 1 lists primary habitat associations and parameters for the San
Bernardino Mountains dudleya.
Table 1. Habitat Associations for San Bernardino Mountains Dudleya
Land Cover Type
Pebble/pavement
plain, pinyon and
juniper woodland,
upper montane
coniferous forest
Habitat
Designation
Primary
3
Habitat Parameters
Granitic and quartzite
(rarely limestone)
substrates; 1,250 to
2,600 meters (4,101
to 8,530 feet)
elevation
Supporting
Information
CNPS 2011
Species Accounts
March 2012
DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
Reproduction
This perennial herb blooms from April to June according to CNPS
(2011), although the Jepson eFlora and the original description of the
subspecies indicate a later blooming period from May to July (Jepson
Flora Project 2011b; Nakai 1987). Though little information is known
regarding the reproduction of this subspecies, dudleyas (Dudleya
spp.) reproduce from offsets and seed. Unlike other genera in the
stonecrop family, dudleyas do not propagate from individual leaf
cuttings (Hodgkiss 2011).
Flowers of San Bernardino Mountains dudleya are small, upright, pale
yellow with red lines (Jepson Flora Project 2011b; Nakai 1987). Other
Dudleya species with small upright yellow flowers are insectpollinated by bees and flies. Based on flower morphology, San
Bernardino Mountains dudleya might also attract hummingbirds.
Levin and Mulroy (1985) examined reproductive strategy (i.e.,
pollination and breeding systems) in 21 Dudleya species. They found
that when maximum energy content is plotted against auto-fertility,
the species fall into three groups. Dudleya abramsii might fit with the
group that has moderate to high nectar production, and low autofertility (Levin and Mulroy 1985).
Ecological Relationships
Endemic to the pebble plains of the San Bernardino Mountains, this
subspecies is associated with several other rare plants, including
Cushenbury milkvetch, Parish’s daisy, Cushenbury buckwheat, and
Cushenbury oxytheca. Pebble plains are sparsely vegetated openings
surrounded by forest with clay soils. Pebble plain habitat is found
between 6,000 and 7,500 feet in elevation, and occurs only within a
92 square mile area in the San Bernardino Mountains (60 FR 39337–
39347). The unique combination of edaphic and climatic factors found
in pebble plain habitats makes it so that several plant species are
either endemic to the San Bernardino Mountains or represent disjunct
occurrences of species more common elsewhere (60 FR 39337–
39347). Other than the habitat associations described above, little
more is known about the ecological relationships of this subspecies.
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Species Accounts
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DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
Population Status and Trends
Global: G3T2, Imperiled (CDFG 2012b)
State: S2.2, Imperiled (CDFG 2012b)
Only 2 of the 12 CNDDB occurrence records include a population size
estimate. Outside the Plan Area 100 to 200 plants were estimated to
occur west of the mouth of Arctic Canyon on the north slope of the San
Bernardino Mountains in 1996. Within the Plan Area, approximately 20
plants were observed on the northeast slope of White Mountain in 1996
(CDFG 2012a). No additional data are available to determine its current
status and population trend.
Threats and Environmental Stressors
San Bernardino Mountains dudleya is threatened by development,
foot traffic, limestone mining, and vehicles, and is possibly threatened
by non-native plants and illegal dumping (CNPS 2011). The
occurrences within the Plan Area are located on private land owned
by Mitsubishi Cement Corp. or the ownership is unknown (CDFG
2012a). Therefore, the populations within the Plan Area could be
vulnerable to the threats listed above.
Conservation and Management Activities
Outside of the Plan Area, San Bernardino Mountains dudleya occurs in
the San Bernardino National Forest under Forest Service management
(CDFG 2012a). There is a memorandum of understanding (MOU)
conservation strategy for pebble plain habitat that addresses San
Bernardino Mountains dudleya, among other sensitive plant species
that occur in pebble plain habitat on Forest Service land (USDA Forest
Service 2005). Protection measures for the federally listed San
Bernardino Mountains carbonate endemic plants may help protect
this subspecies. The draft recovery plan for these species includes
conservation and management of pebble plain habitat and also
addresses the threat of limestone mining (USFWS 1997).
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
Data Characterization
In general, data availability for San Bernardino Mountains dudleya is
poor. Little is known regarding this dudleya’s reproductive biology,
ecological relationships, and population trends.
Management and Monitoring Considerations
Little information is known regarding San Bernardino Mountains
dudleya’s current status in the Plan Area.
Predicted Species Distribution in Plan Area
There are 63,893 acres of modeled suitable habitat for San
Bernardino Mountains dudleya in the Plan Area. Modeled suitable
habitat occurs in the western portion of the Plan Area along the edge
of San Bernardino National Forest from 4,100 to 8,600 feet in
elevation. Modeled suitable habitat includes woodland and forest
vegetation communities with granitic and sedimentary substrates.
Appendix C includes specific model parameters and a figure showing
the modeled suitable habitat in the Plan Area.
Literature Cited
60 FR 39337–39347. Proposed Rule: “Endangered and Threatened
Wildlife and Plants; Proposed Endangered or Threatened
Status for Seven Plants From the Mountains of Southern
California.” August 2, 1995.
CCH (Consortium of California Herbaria). 2011. Accession results for
“Dudleya abramsii ssp. affinis.” Accessed December 27, 2011.
http://ucjeps.berkeley.edu/consortium/.
CDFG (California Department of Fish and Game). 2012a. “Dudleya
abramsii ssp. affinis.” 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.
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
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.
CNPS (California Native Plant Society). 2011. “Dudleya abramsii ssp.
affinis.” Inventory of Rare and Endangered Plants. Online ed.
Version 8-01a. Sacramento, California: CNPS. Accessed
November 2011. http://www.cnps.org/inventory.
Deacon, M. 2007. “Cement Plant Celebrates 50 Years in the High
Desert.” Victorville Daily Press. Online ed. June 3, 2007. Accessed
November 29, 2011. http://www.vvdailypress.com/news/
cement-1285-plant-community.html.
Hodgkiss, R.J. 2011. “The Dudleya Page.” The Succulent Plant Page.
Last revised: November 24, 2011. Accessed December 2, 2011.
http://www.succulent-plant.com/families/crassulaceae/
dudleya.html.
Jepson Flora Project. 2011a. “Crassulaceae, Stonecrop Family.” S. Boyd,
ed. Jepson eFlora [v. 1.0]. Berkeley, California: University of
California. Accessed December 5, 2011.
http://ucjeps.berkeley.edu/IJM.html.
Jepson Flora Project. 2011b. “Dudleya abramsii ssp. affinis.” K.M. Nakai,
ed. Jepson eFlora [v. 1.0]. Berkeley, California: University of
California. Accessed December 5, 2011.
http://ucjeps.berkeley.edu/IJM.html.
Levin, G. A., and T. W. Mulroy. 1985. “Floral mechanisms, nectar
production, and breeding systems in Dudleya subgenus
Dudleya (Crassulaceae).” Transactions of the San Diego Society
of Natural History 21(3): 57–70. http://biostor.org/
reference/74442.text
Nakai, K.M. 1987. “Some New and Reconsidered California Dudleya
(Crassulacaeae).” Madroño 34(4):334–353.
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Species Accounts
March 2012
DRAFT
March 2012
PLANTS
San Bernardino Mountains Dudleya (Dudleya abramsii ssp. affinis)
NatureServe. 2011. “Dudleya abramsii ssp. affinis.” NatureServe
Explorer: An Online Encyclopedia of Life. Version 7.1. Arlington,
Virginia: NatureServe. Last updated July 2011. Accessed
December 2011. http://www.natureserve.org/explorer.
USDA (U.S. Department of Agriculture) Forest Service. 2005. Land
Management Plan. Part 3 Design Criteria for the Southern
California National Forests: Angeles National Forest, Cleveland
National Forest. Los Padres National Forest, San Bernardino
National Forest, “Appendix H – Species Guidance Summary.”
September 2005. Accessed November 29, 2011.
https://fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5337
818.pdf.
USFWS (U.S. Fish and Wildlife Service). 1997. San Bernardino
Mountains Carbonate Plants Draft Recovery Plan. U.S. Fish and
Wildlife Service: Portland, Oregon.
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March 2012