Astragalus osterhoutii - M.E. Jones
Osterhout's Milkvetch
Other English Common Names: Kremmling Milkvetch
Other Common Names: Kremmling milkvetch
Taxonomic Status: Accepted
Related ITIS Name(s): Astragalus osterhoutii M.E. Jones (TSN 25618)
Unique Identifier: ELEMENT_GLOBAL.2.155315
Element Code: PDFAB0F6E0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Pea Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Fabales Fabaceae Astragalus
Check this box to expand all report sections:
Concept Reference
Help
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.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Astragalus osterhoutii
Conservation Status
Help

NatureServe Status

Global Status: G1
Global Status Last Reviewed: 27Aug2012
Global Status Last Changed: 19Jan1984
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G1 - Critically Imperiled
Reasons: Endemic to small area in Grand County, Colorado, mostly near a single creek. Construction of a dam in 1995 flooded at least 1 occurrence and impacted others. Other threats to this species include off-road vehicles, road maintenance, oil and gas drilling, and mining.
Nation: United States
National Status: N1

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Colorado (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (13Jul1989)
U.S. Fish & Wildlife Service Lead Region: R6 - Rocky Mountain

NatureServe Global Conservation Status Factors

Range Extent Comments: Endemic to Grand County, Colorado. Estimated range is 120 square kilometers, calculated in GIS in 2008 by the Colorado Natural Heritage Program by drawing a minimum convex polygon around the known occurrences. Imprecisely reported occurrences are not included.

Area of Occupancy: 2-5 4-km2 grid cells
Area of Occupancy Comments: The total area occupied by the mapped occurrences is 790 acres (calculated by the Colorado Natural Heritage Program in 2012). Imprecisely reported occurrences are not included.

Number of Occurrences: 1 - 5
Number of Occurrences Comments: There are 6 principal occurrences documented in the Colorado Natural Heritage Program database. One of the 6 occurrences has not been observed in over 20 years.

Population Size Comments: Total estimated sum of individuals from 5 of the 6 documented occurrences is 10,385. The remaining occurrence does not report the number of individuals, but does report the species as 'locally abundant' . The Federal Register (1998) states that there are 25,000 to 50,000 individuals.

Number of Occurrences with Good Viability/Integrity: Few (4-12)
Viability/Integrity Comments: There are 5 occurrences with an A or B rank.

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: The major threat is from habitat destruction from all terrain vehicles going off road. OHVs target the barren hillsides that are Astragalus osterhoutii's habitat. The Colorado Natural Areas Program has worked with the State Land Board and the local OHV community on the Idiot's Hill population to mitigate OHV impacts, by keeping folks on trail and away from A. osterhoutii, and in 2011 put up an interpretative sign at the site. Other threats include road maintenance (including weed control and road widening), mineral extraction/mining, and expansion of Wolford Mountain Reservoir. Some occurrences were impacted by habitat loss due to the creation of Wolford Mountain Reservoir. The threat still exists because of future plans to enlarge the reservoir. Mineral extraction is becoming a more imminent threat because of increased demands from mining interests. The primary pollinator is a ground bumble bee which could also be impacted by surface disturbance and inundation.

Short-term Trend: Unknown
Short-term Trend Comments: BLM and the Denver Botanic Gardens have been monitoring trends in population size for several years (Dawson 2009).

Long-term Trend: Unknown
Long-term Trend Comments: Unknown.

Intrinsic Vulnerability Comments: Restricted to a specialized soil type which is vulnerable to alteration by human activities.

Other NatureServe Conservation Status Information

Distribution
Help
Global Range: Endemic to Grand County, Colorado. Estimated range is 120 square kilometers, calculated in GIS in 2008 by the Colorado Natural Heritage Program by drawing a minimum convex polygon around the known occurrences. Imprecisely reported occurrences are not included.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States CO

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
CO Grand (08049)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
14 Colorado headwaters (14010001)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
Basic Description: A perennial herb, 50 to 100 cm tall, with 15 - 30 mm long linear leaflets and several to many erect, rush-like stems. Large cream-colored flowers bloom June-August, followed by laterally compressed, 40 mm pendulous pods (Spackman et al. 1997, NatureServe 2006).
General Description: Relatively tall (up to 100 cm) herbaceous, perennial plants with numerous bright green stems and white to cream colored flowers. Flowers are about 2 cm long and clustered toward the end of branches. Leaflets are 15-30 mm long, subsessile, and linear-oblong or lanceolate. Pods are 40 mm in length, stipitate, and strongly laterally compressed. Pods are bright green and turn red/maroon as they mature (Spackman et al. 1997).
Duration: PERENNIAL
Reproduction Comments: Flowers bloom June - August, followed by fruit.
Terrestrial Habitat(s): Shrubland/chaparral
Habitat Comments: Highly seleniferous, grayish-brown clay soils derived from shales of the Niobrara, Pierre, and Troublesome formations. On moderate slopes, sometimes found growing up through sagebrush (Spackman et al. 1997).  Associated species include: Artemesia tridentata, Chrysothamnus viscidiflorus, Gutierrezia sarothrae, Eurotia lanata, Phlox hoodii, Eriogonum brevicaule, and Agropogon smithii.
Economic Attributes
Help
Economically Important Genus: Y
Management Summary Not yet assessed
Help
Population/Occurrence Delineation
Help
Minimum Criteria for an Occurrence: Any naturally occurring population that is separated by a sufficient distance or barrier from a neighboring population. As a guideline, EOs are separated by either: 1 mile or more across unsuitable habitat or altered and unsuitable areas; or 2 miles or more across apparently suitable habitat not known to be occupied. Justification: The rationale for this large a separation distance across suitable but apparently unoccupied habitat is that it is likely additional research will find this habitat to be occupied. It can often be assumed that apparently unconnected populations will eventually be found to be more closely connected; these are best regarded as suboccurrences. No information on mobility of pollen and propagules is available on which to base the separation distance for this species.
Date: 27Sep2000
Author: Spackman, S., and D. Anderson.
Population/Occurrence Viability
Help
Excellent Viability: Size: 1000 or more individuals (based on available EOR data). Condition: the occurrence has an excellent likelihood of long-term viability as evidenced by the presence of multiple age classes and evidence of flowering and fruiting, indicating that the reproductive mechanisms are intact. This occurrence should be in a high-quality site with less than 1% cover of exotic plant species and/or no significant anthropogenic disturbance. Landscape Context: the occurrence is surrounded by an area that is unfragmented and includes the ecological processes needed to sustain this species. A suitable natural disturbance regime (which may include fire), suitable soil chemistry and nutrient levels, and a lack of unnatural flooding is required by this species to persist. Justification: Large populations in high quality sites are presumed to contain a high degree of genetic variability, to have a low susceptibility to the effects of inbreeding depression, and to be relatively resilient.
Good Viability: Size: 100 to 1000 individuals (based on available EOR data). Condition: the occurrence should have a good likelihood of long-term viability as evidenced by the presence of multiple age classes and evidence of flowering and fruiting, indicating that the reproductive mechanisms are intact. Anthropogenic disturbance within the occurrence is minimal. If exotic species are present, they comprise less than 10% of the total ground cover. Landscape Context: the surrounding landscape should contain the ecological processes needed to sustain the occurrence but may be fragmented and/or impacted by humans.
Fair Viability: Size: 20 to 100 individuals (based on available EOR data). Condition: The occurrence may be less productive than the above situations, but is still viable, with multiple age classes and evidence of flowering and fruiting, indicating that the reproductive mechanisms are intact. The occupied habitat is somewhat degraded (exotic plant species make up between 10-50% of the total ground cover and/or there is a moderate level of anthropogenic disturbance). Landscape Context: there may be significant human disturbance, but the ecological processes needed to sustain the species are still intact.
Poor Viability: Size: Less than 20 individuals (based on available EOR data). Condition: little or no evidence of successful reproduction is observed (poor seedling recruitment, no flowering or fruiting observed, or poor age class distribution). Exotic plant species make up greater than 50% of the total ground cover, and/or there is a significant level of human disturbance. Landscape context: the surrounding area is fragmented with many ecological processes no longer intact. The occurrence has a low probability of long-term persistence due to inbreeding depression, natural stochastic events, and its intrinsic vulnerability to human impacts.
Justification: Justification: EOs not meeting "C"-rank criteria are likely to have a very high probability of inbreeding depression and extirpation due to natural stochastic processes and/or occur in degraded habitat with low long-term potential for survival.
Key for Ranking Species Element Occurrences Using the Generic Approach (2008).
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 27Aug2012
NatureServe Conservation Status Factors Author: S. Spackman, rev. Maybury/Spackman (1996), rev. Spackman, S. and D. Anderson (2000), rev. Neuhaus, K., J. Handwerk, and S. Panjabi (2006), rev. Handwerk, J. (2009), rev. Handwerk, J. (2012)

Element Ecology & Life History Edition Date: 15Jul2011
Element Ecology & Life History Author(s): rev. SSP (2015)

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

References
Help
  • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.


  • Barneby, R. C. 1964. Atlas of North American Astragalus. Memoirs of New York Botanical Garden, vol. 13. New York Botanical Garden, Bronx, NY.

  • Baskin, C.C., J.M. Baskin and E. Quarterman. 1972. Observations on the ecology of Astragalus tennesseensis. Amer. Midl. Natur. 88(1): 167-182.

  • Colorado Native Plant Society. 1989. Rare plants of Colorado. Rocky Mountain Nature Association, Colorado Native Plant Society, Estes Park, Colorado. 73 pp.

  • Dawson, C. 2009. Personal communication with Colorado Natural Heritage Program staff regarding BLM rare plant monitoring in Colorado.

  • Dawson, C.A. 1999. The autecology of Astragalus osterhoutii Jones. Dissertation. University of Denver, Denver, CO.

  • Elliott, B. A., S. Spackman Panjabi, B. Kurzel, B. Neely, R. Rondeau, M. Ewing. 2009. Recommended Best Management Practices for Plants of Concern. Practices developed to reduce the impacts of oil and gas development activities to plants of concern. Unpublished report prepared by the Rare Plant Conservation Initiative for the National Fish and Wildlife Foundation.

  • Green, T.W. and G.E. Bohart. 1975. The pollination ecology of Astragalus cibarius and Astragalus utahensis (Leguminosae). Amer. J. Bot. 62(4): 370-386.

  • 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.

  • NatureServe. Central Databases. Arlington, Virginia. U.S.A. Online. Available: http://www.natureserve.org/explorer/

  • Neely, B., S. Panjabi, E. Lane, P. Lewis, C. Dawson, A. Kratz, B. Kurzel, T. Hogan, J. Handwerk, S. Krishnan, J. Neale, and N. Ripley. 2009. Colorado Rare Plant Conservation Strategy, Developed by the Colorado Rare Plant conservation Initiative. The Nature Conservancy, Boulder, Colorado, 117 pp.

  • O'Kane, S. L. 1988. Colorado's Rare Flora. Great Basin Naturalist. 48(4):434-484.

  • Panjabi, S. and B. Neely. 2011. Middle Park Conservation Action Plan, 2011 Update. Prepared by The Nature Conservancy and the Colorado Natural Heritage Program. Unpublished report prepared for the National Fish and Wildlife Foundation.

  • Rocky Mountain Society of Botanical Artists. 2009. RARE Imperiled Plants of Colorado, a traveling art exhibition. Exhibition catalogue developed by the Denver Botanic Gardens and Steamboat Art Museum.

  • Spackman, S., B. Jennings, J. Coles, C. Dawson, M. Minton, A. Kratz, and C. Spurrier. 1997. Colorado rare plant field guide. Prepared for Bureau of Land Management, U.S. Forest Service and U.S. Fish and Wildlife Service by Colorado Natural Heritage Program.

  • Taliga, Christine E., 2011. Plant Guide for Kremmling milkvetch (Astragalus osterhoutii). USDA-Natural Resources Conservation Service, Colorado State Office. Denver, CO 80225-0426.

  • U. S. Fish and Wildlife Service. 1988. Proposal to determine Astragalus osterhoutii and Penstemon penlandii to be endangered species. Federal Register 53(128): 25181-25185.

  • USDA, NRCS. 2013. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.

  • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.

  • Western Resource Development. 1990. Osterhout milkvetch inventory: Kremmling Resource Area, Grand County, Colorado.

Use Guidelines & Citation

Use Guidelines and Citation

The Small Print: Trademark, Copyright, Citation Guidelines, Restrictions on Use, and Information Disclaimer.

Note: All species and ecological community data presented in NatureServe Explorer at http://explorer.natureserve.org were updated to be current with NatureServe's central databases as of March 2018.
Note: This report was printed on

Trademark Notice: "NatureServe", NatureServe Explorer, The NatureServe logo, and all other names of NatureServe programs referenced herein are trademarks of NatureServe. Any other product or company names mentioned herein are the trademarks of their respective owners.

Copyright Notice: Copyright © 2018 NatureServe, 4600 N. Fairfax Dr., 7th Floor, Arlington Virginia 22203, U.S.A. All Rights Reserved. Each document delivered from this server or web site may contain other proprietary notices and copyright information relating to that document. The following citation should be used in any published materials which reference the web site.

Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

Restrictions on Use: Permission to use, copy and distribute documents delivered from this server is hereby granted under the following conditions:
  1. The above copyright notice must appear in all copies;
  2. Any use of the documents available from this server must be for informational purposes only and in no instance for commercial purposes;
  3. Some data may be downloaded to files and altered in format for analytical purposes, however the data should still be referenced using the citation above;
  4. No graphics available from this server can be used, copied or distributed separate from the accompanying text. Any rights not expressly granted herein are reserved by NatureServe. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any trademark of NatureServe. No trademark owned by NatureServe may be used in advertising or promotion pertaining to the distribution of documents delivered from this server without specific advance permission from NatureServe. Except as expressly provided above, nothing contained herein shall be construed as conferring any license or right under any NatureServe copyright.
Information Warranty Disclaimer: All documents and related graphics provided by this server and any other documents which are referenced by or linked to this server are provided "as is" without warranty as to the currentness, completeness, or accuracy of any specific data. NatureServe hereby disclaims all warranties and conditions with regard to any documents provided by this server or any other documents which are referenced by or linked to this server, including but not limited to all implied warranties and conditions of merchantibility, fitness for a particular purpose, and non-infringement. NatureServe makes no representations about the suitability of the information delivered from this server or any other documents that are referenced to or linked to this server. In no event shall NatureServe be liable for any special, indirect, incidental, consequential damages, or for damages of any kind arising out of or in connection with the use or performance of information contained in any documents provided by this server or in any other documents which are referenced by or linked to this server, under any theory of liability used. NatureServe may update or make changes to the documents provided by this server at any time without notice; however, NatureServe makes no commitment to update the information contained herein. Since the data in the central databases are continually being updated, it is advisable to refresh data retrieved at least once a year after its receipt. The data provided is for planning, assessment, and informational purposes. Site specific projects or activities should be reviewed for potential environmental impacts with appropriate regulatory agencies. If ground-disturbing activities are proposed on a site, the appropriate state natural heritage program(s) or conservation data center can be contacted for a site-specific review of the project area (see Visit Local Programs).

Feedback Request: NatureServe encourages users to let us know of any errors or significant omissions that you find in the data through (see Contact Us). Your comments will be very valuable in improving the overall quality of our databases for the benefit of all users.