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Astragalus ertterae

Barneby & Shevock

Ertter's Milkvetch

G2Imperiled Found in 2 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.153279
Element CodePDFAB0FB30
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderFabales
FamilyFabaceae
GenusAstragalus
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
Rank Method Rank calculation - Biotics v2
Review Date2024-06-12
Change Date2013-08-20
Edition Date2024-06-12
Edition AuthorsBittman, R.L., and J. Shevock (1987), rev. G. Davis (5/07), rev. Johnson, J. (2024)
Threat ImpactMedium
Range Extent100-250 square km (about 40-100 square miles)
Number of Occurrences6 - 20
Rank Reasons
Astragalus ertterae is a perennial herb that is endemic to California, USA, and known only from nine occurrences in the Walker Pass area in Kern County. Direct human threats are low, but the plants are apparently sensitive to drought which may be worsened by climate change. Additional surveys are needed to determine population sizes at newly discovered occurrences.
Range Extent Comments
Astragalus ertterae occurs in the western United States where it is endemic to the Walker Pass area, Kern County (west slope of southern Sierra Nevada), California. Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 2003 and 2024 (CNDDB 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1993 and 2024, it is estimated that there are six occurrences range-wide (CNDDB 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024).
Threat Impact Comments
The Pacific Crest Trail bisects both populations. Trampling and trail use present a minor threat. Grazing is also a possible threat, but plants do not appear to be browsed by cattle (CNDDB 2024, NatureServe 2024). Climate change in this area is expected to consist of warmer temperatures and changes in seasonality of precipitation (UC Berkeley 2024), which could affect this upland species' ability to grow and reproduce.
Ecology & Habitat

Habitat

Astragalus ertterae grows in sandy loamy granitic soils in pinyon pine woodlands with canyon live oak (FNA 2023).
Terrestrial Habitats
Forest/WoodlandWoodland - Conifer
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
2 - Agriculture & aquacultureLarge (31-70%)Slight or 1-10% pop. declineHigh (continuing)
2.3 - Livestock farming & ranchingLarge (31-70%)Slight or 1-10% pop. declineHigh (continuing)
6 - Human intrusions & disturbanceSmall (1-10%)Moderate - slightHigh (continuing)
6.1 - Recreational activitiesSmall (1-10%)Moderate - slightHigh (continuing)
11 - Climate change & severe weatherPervasive (71-100%)Moderate or 11-30% pop. declineModerate (short-term)
11.1 - Habitat shifting & alterationPervasive (71-100%)Moderate or 11-30% pop. declineModerate (short-term)

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (2)
California (2)
AreaForestAcres
Domeland Add.Sequoia National Forest3,046
ScodiesSequoia National Forest725
References (9)
  1. Cal-Adapt. 2024. University of California, Berkeley, Geospatial Innovation Facility. https://cal-adapt.org/tools/maps-of-projected-change/ Accessed 2024-06-12.
  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 Natural Diversity Database (CNDDB). 2024. RareFind Version 5.3.0. California Department of Fish and Game, Sacramento.
  4. Flora of North America Editorial Committee (FNA). 2023. Flora of North America north of Mexico. Vol. 11. Magnoliophyta: Fabaceae, parts 1+2. Oxford Univ. Press, New York. xxvii + 1108 pp.
  5. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  6. 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.
  7. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. Skinner, M.W., and B.M. Pavlik, eds. 1997 (1994). Inventory of rare and endangered vascular plants of California. 1997 Electronic Inventory Update of 1994 5th edition, California Native Plant Society, Special Publication No. 1, Sacramento.
  9. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).