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Home/Species/ Chaco Milkvetch

Astragalus micromerius

Barneby

Chaco Milkvetch

G3Vulnerable Found in 1 roadless area NatureServe Explorer →
G3VulnerableGlobal Rank
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.130484
Element CodePDFAB0F5B0
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 Date2024-07-26
Change Date2011-02-15
Edition Date2024-07-26
Edition AuthorsDeBruin, E. and K. Maybury, rev. L. Oliver and D. Roth (2004), rev. C. Nordman (2024).
Threat ImpactLow
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences6 - 20
Rank Reasons
Chaco Milkvetch (Astragalus micromerius) occurs in the southwestern United States, it is endemic to the Four Corners area of northwestern New Mexico in the high desert of McKinley, Rio Arriba and San Juan counties. It is known to occur in fewer than twenty widely scattered locations. It is believed that this species is under observed or over looked, and is more abundant than is known. It is a low growing, long-lived perennial, with few potential threats, which include mining, recreation associated with off-road vehicle impacts, and extreme drought such as may be associated with climate change.
Range Extent Comments
Chaco Milkvetch (Astragalus micromerius) occurs in the southwestern United States where it is endemic to the Four Corners area of northwestern New Mexico in the high desert of McKinley, Rio Arriba and San Juan counties. Range extent was estimated to be 14,900 square kilometers, using herbarium specimens and NatureServe Network occurrence data collected between 1993 and 2024 (Sivinski 1999, Heil et al. 2013, Allred et al. 2020, GBIF 2024, NatureServe 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens and NatureServe Network occurrence data documented between 1993 and 2024, it is estimated that there are between sixteen and eighteen occurrences rangewide (GBIF 2024, NatureServe 2024, NMNHP 2024, SEINet 2024). However, it is suspected that there are more locations not yet discovered. It is believed that this species is under-observed (D. Roth, pers. comm., n.d.). It is sporadically distributed in isolated populations across its range (Sivinski 1999).
Threat Impact Comments
This species is generally not threatened by human activities due to the remote places where it grows. There are some potential threats as the desert is being used more for various activities, and these potential threats include trampling, off road vehicle use, and mining activities (D. Roth, pers. comm., n.d.). Extreme drought such as may be associated with climate change is also a threat, it is considered "Extremely Vulnerable" to climate change in the 2040-2069 time horizon (Still et al. 2015).
Ecology & Habitat

Habitat

This species grows in pinyon-juniper woodland and Great Basin desert scrub. It is associated with calcareous sandstone or gypsum substrates and specifically is found on sandstone mixed with Todilto gypsum or limestone (Sivinski 1999), on shelving ledges of sandstone or limey sandstone cliffs, and occasionally on talus slopes, steep slopes of Mancos clay, or partly submerged in drifting sand at 2020-2235 m elevation (New Mexico Native Plant Protection Advisory Committee 1984, Heil et al. 2013, Allred et al. 2020).

Reproduction

This species flowers from July to August (Sivinski 1999, Heil et al. 2013).
Terrestrial Habitats
Forest/WoodlandWoodland - ConiferDesertBare rock/talus/screeCliff
Other Nations (1)
United StatesN3
ProvinceRankNative
New MexicoS3Yes
Navajo NationS2Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
3.2 - Mining & quarryingSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
6 - Human intrusions & disturbanceSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
6.1 - Recreational activitiesSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
11 - Climate change & severe weatherLarge (31-70%)Serious - moderateLow (long-term)
11.2 - DroughtsLarge (31-70%)Serious - moderateLow (long-term)

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Plant Characteristics
DurationPERENNIAL, Long-lived, SUMMER-FLOWERING
Economic Value (Genus)Yes
Roadless Areas (1)
New Mexico (1)
AreaForestAcres
Bull CanyonCarson National Forest11,512
References (14)
  1. Allred, K.W., E.M. Jercinovic, and R.D. Ivey. 2020. Flora Neomexicana III: An Illustrated Identification Manual, Second Edition. Part 2: Dicotyledonous Plants.
  2. Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.
  3. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  4. Heil, K.D, S.L. O'Kane Jr., L.M. Reeves, and A. Clifford. 2013. Flora of the Four Corners Region. Vascular Plants of the San Juan River Drainage: Arizona, Colorado, New Mexico, and Utah. Monographs in systematic botany from the Missouri Botanical Garden, Vol. 124, Missouri Botanical Garden Press, St. Louis, MO. xvi + 1098 pp.
  5. 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.
  6. Martin, W.C., and C.R. Hutchins. 1980-1981. A flora of New Mexico. 1980, Vol. 1; 1981, Vol. 2. J. Cramer, in der A.R. Gantner Verlag, K.G., Vaduz, Liechtenstein. 2591 pp.
  7. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. New Mexico Native Plant Protection Advisory Committee. 1984. A handbook of rare and endemic plants of New Mexico. Univ. New Mexico Press, Albuquerque. 291 pp.
  9. New Mexico Natural Heritage Program (NMNHP). 2024. Element Subnational Ranking Form: <i>Astragalus micromerius</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 26 July 2024).
  10. Roth, Daniela. Botanist, Navajo Natural Heritage Program, Navajo Nation, Window Rock, Arizona, USA.
  11. Sivinski, R. 1999. <i>Astragalus micromerius</i> [species profile]. New Mexico Rare Plants. New Mexico Rare Plant Technical Council. Online. Available: https://nmrareplants.unm.edu/node/28 (Accessed 2013, 2024)
  12. Sivinski, R., and K. Lightfoot, eds. 1995. Inventory of rare and endangered plants of New Mexico. 3rd edition. Miscellaneous Publication No. 4, Forestry Division, New Mexico Energy, Minerals and Natural Resources Dept., Santa Fe.
  13. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).
  14. Still, S., A. Frances, A. Treher, and L. Oliver, L. 2015. Using Two Climate Change Vulnerability Assessment Methods to Prioritize and Manage Rare Plants: A Case Study. Natural Areas Journal 35(1):106–21.