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Astragalus albens

Greene

Cushenbury Milkvetch

G1Critically Imperiled Found in 4 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
Very high - highThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.159120
Element CodePDFAB0F0A0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderFabales
FamilyFabaceae
GenusAstragalus
Other Common Names
cushenbury milkvetch (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Review Date2015-10-20
Change Date1988-03-08
Edition Date2003-07-23
Edition AuthorsBittman, R.L., rev. Maybury (1997), rev. L. Oliver (2003), rev. K. Gravuer (2009)
Threat ImpactVery high - high
Range Extent<100 square km (less than about 40 square miles)
Number of Occurrences6 - 20
Rank Reasons
Restricted to a carbonate belt in the northeastern San Bernardino Mountains, San Bernardino County, California. Approximately 16 occurrences are believed extant (with another 2 historical and 1 of unknown status) within an area of approximately 80 square kilometers. Population size was estimated to be 7000-7500 plants, but is likely less in drought years. Habitat destruction and degradation associated with limestone mining is the major threat to this species. Other threats include off-highway vehicle use, target shooting, road building and maintenance, trash dumping, and potential development. The U.S. Fish and Wildlife Service (2002) has designated Critical Habitat and the U.S. Forest Service has developed the Carbonate Habitat Management Strategy (2003) with the aim of mitigating these threats.
Range Extent Comments
Restricted to a carbonate belt in the northeastern San Bernardino Mountains (east slope of the Transverse Range) extending from Dry Canyon southeastward to the head of Lone Valley (approximately 24 km) in and adjacent to San Bernardino National Forest; San Bernardino County, California. Using GIS tools, range extent was calculated to be approximately 82 square km.
Occurrences Comments
Approximately 16 occurrences are believed extant, with another 2 historical and 1 of unknown status, when mapped using the separation distance of the California Natural Diversity Database (CNDDB). Other reports, using a much smaller separation distance, have broken the total population into a smaller number of "patches" (e.g. 91 patches reported by Neel 2008).
Threat Impact Comments
Limestone mining is the major threat to this species. Habitat destruction and degradation result from direct removal of mined minerals, disposal of overburden on adjacent unmined habitat, associated impacts such as windblown dust, and road construction (USFWS 1997). Other threats include off-highway vehicle use, target shooting, road building and maintenance, trash dumping, and potential development. The U.S. Fish and Wildlife Service (2002) has designated Critical Habitat and the U.S. Forest Service has developed the Carbonate Habitat Management Strategy (2003) with the aim of mitigating these threats. These conservation plans include most, but not all, known occurrences of A. albens (Neel 2008).
Ecology & Habitat

Habitat

Primarily found on soils derived directly from decomposing limestone bedrock, especially on ridgetops and on open, very rocky, relatively gentle slopes at 1500-2000 m elevation. Also known from lower elevations (down to about 1170 m) in rocky washes that receive limestone outwash and from granite and granite-quartzite substrates. Plant communities are pinyon-juniper woodland, pinyon woodland, Joshua tree woodland, blackbrush scrub, and creosote bush-blackbrush scrub. Occupied sites tend to have low overstory and shrub canopy cover, high soil pH, and a high percentage of soil calcium. Associated species include Fremontodendron californicum (California Flannelbush), Coleogyne ramosissima (Blackbrush), Echinocereus triglochidiatus var. mojavensis (King-Cup Cactus), Prunus fasciculata (Desert Almond), and Yucca schidigera (Mojave Yucca).

Ecology

Establishes after disturbances like fire from the seed bank (Sclafani 2013).

Reproduction

Plants have a taproot and show no evidence of vegetative reproduction (Neel 2008). Fruits and seeds have no specialized dispersal mechanism (Neel 2008).
Terrestrial Habitats
Forest/WoodlandWoodland - ConiferShrubland/chaparralDesert
Other Nations (1)
United StatesN1
ProvinceRankNative
CaliforniaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentLarge (31-70%)Serious or 31-70% pop. declineModerate - low
3 - Energy production & miningPervasive - largeExtreme - seriousHigh (continuing)
3.2 - Mining & quarryingPervasive - largeExtreme - seriousHigh (continuing)
4 - Transportation & service corridorsPervasive - largeExtreme - seriousHigh (continuing)
4.1 - Roads & railroadsPervasive - largeExtreme - seriousHigh (continuing)
6 - Human intrusions & disturbancePervasive - largeExtreme - seriousHigh (continuing)
6.1 - Recreational activitiesPervasive - largeExtreme - seriousHigh (continuing)
9 - PollutionPervasive - largeExtreme - seriousHigh (continuing)
9.4 - Garbage & solid wastePervasive - largeExtreme - seriousHigh (continuing)
9.5 - Air-borne pollutantsPervasive - largeExtreme - seriousHigh (continuing)

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Plant Characteristics
DurationANNUAL, PERENNIAL, Short-lived
Economic Value (Genus)Yes
Roadless Areas (4)
California (4)
AreaForestAcres
Granite PeakSan Bernardino National Forest450
Granite PeakSan Bernardino National Forest450
Heartbreak RidgeSan Bernardino National Forest4,455
SugarloafSan Bernardino National Forest8,206
References (10)
  1. Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.
  2. California Department of Fish and Game. 2000. Natural Diversity Database (RareFind 2), Version 2.1.2, January 25, 2000. Downloaded in 2003.
  3. California Native Plant Society (CNPS). 2001. Inventory of Rare and Endangered Plants of California (sixth edition). Rare Plant Scientific Advisory Committee, David P. Tibor, Convening Editor. California Native Plant Society. Sacramento, CA. x + 388pp.
  4. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  5. Neel, M. 2008. Patch connectivity and genetic diversity conservation in the federally endangered and narrowly endemic plant species <i>Astragalus albens </i>(Fabaceae). Biological Conservation 141: 938-955.
  6. Olson, T. G. 2003. Carbonate Habitat Management Strategy. San Bernardino National Forest Association. Online. Available: http://www.fs.fed.us/r5/scfpr/projects/lmp/docs/carbonate-strategy.pdf (Accessed 2009)
  7. Sclafani, C.J. 2013. <i>Astragalus albens</i>. In: Fire Effects Information System. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Available: http://www.fs.fed.us/database/feis/. Accessed 26 Sep 2016.
  8. U.S. Fish and Wildlife Service. 1994. Five plants from the San Bernardino Mountains in southern California determined to be threatened or endangered. Federal Register 59(163): 43652-43664.
  9. U.S. Fish and Wildlife Service (USFWS). 1997. San Bernardino Mountains Carbonate Plants Draft Recovery Plan. U.S. Fist and Wildlife Service, Portland, Oregon. 51 pp.
  10. U.S. Fish and Wildlife Service (USFWS). 2002. Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Five Carbonate Plants From the San Bernardino Mountains in Southern California; Final Rule. Federal Register 67(247): 78570-78610. 24 December 2002.