Astragalus schmolliae - C.L. Porter
Schmoll's Milkvetch
Other Common Names: Schmoll's milkvetch
Taxonomic Status: Accepted
Related ITIS Name(s): Astragalus schmolliae C.L. Porter (TSN 25668)
Unique Identifier: ELEMENT_GLOBAL.2.143808
Element Code: PDFAB0F7W0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Pea Family
Image 12082

Public Domain

 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Fabales Fabaceae Astragalus
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Concept Reference
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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 schmolliae
Conservation Status
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NatureServe Status

Global Status: G1
Global Status Last Reviewed: 05Sep2012
Global Status Last Changed: 05Dec1988
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G1 - Critically Imperiled
Reasons: Known only from Chapin Mesa in Mesa Verde National Park and the Ute Mountain Ute Reservation in Montezuma County, Colorado. Although the species is abundant there, much of its occupied habitat has been burned and is threatened by invasive exotics. Additionally, the species has apparently not crossed the canyons to establish itself on other adjacent mesa-tops.
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): C: Candidate (05Dec2014)
U.S. Fish & Wildlife Service Lead Region: R6 - Rocky Mountain

NatureServe Global Conservation Status Factors

Range Extent Comments: Endemic to Montezuma County, Colorado. It is found in the vicinity of Chapin Mesa extending south approximately 6 miles into the Ute Mountain Ute Reservation. Estimated range is 18 square kilometers, calculated in 2008 by the Colorado Natural Heritage Program in GIS by drawing a minimum convex polygon around the known occurrences. Imprecisely reported occurrences are not included.

Area of Occupancy: 6-25 4-km2 grid cells
Area of Occupancy Comments: The total area occupied by the mapped occurrences is 2033 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 4 principal occurrences documented in the Colorado Natural Heritage Program database. One of the occurrences has not been observed in over 20 years. The occurrences are all in the vicinity of Chapin Mesa in Mesa Verde National Park and the adjacent Ute Mountain Ute Reservation.

Population Size Comments: 294,499 individuals have been documented in Mesa Verde National Park (Anderson 2004). Large numbers of individuals are likely to occur on the Ute Mountain Ute Reservation but this area has not been surveyed.

Number of Occurrences with Good Viability/Integrity: Very few (1-3)
Viability/Integrity Comments: There are 2 occurrences with an A or B rank.

Overall Threat Impact: High
Overall Threat Impact Comments: The primary threat to the species is the invasion of weeds into burned areas which are occupied by Astragalus schmolliae. Musk thistle (Carduus nutans) is particularly invasive in burned areas of southern Mesa Verde National Park (MVNP), and has been observed invading areas occupied by A. schmolliae. Cheatgrass (Bromus tectorum) is also invading burned areas occupied by A. schmolliae. Visitor impacts to A. schmolliae within MVNP are localized and minimal, limited to trampling of an occasional plant growing adjacent to a trail or road (Anderson 2004). Outside of MVNP boundaries the threats are grazing and road construction (O'Kane 1988).

Short-term Trend: Decline of 10-50%
Short-term Trend Comments: The population declined 39% as a result of a severe drought in 2002. Additionally, two recent fires have impacted a large portion of the known population of Astragalus schmolliae in Mesa Verde National Park; the Chapin 5 fire in 1996, and the Long Mesa Fire in 2002. Statistical analysis by Anderson 2004, suggests that burning did not significantly impact plant mortality, but long term impacts of fire (i.e., weed invasion) are likely to cause a decline. In 2011, Kuhn and Anderson resampled belt transects for A. schmolliae that were sampled in 2001 and 2003 on Chapin Mesa. Results show a decline in density from 2001 (measured in number of A. schmolliae individuals per square meter). A comparison of the number of individuals present in unburned vs. burned transects indicated no difference between 2001 and 2003 data. Results from 2003 and 2011 also indicated no difference. Additionally, the four demography plots initially sampled in 2003 by Anderson, were resampled in 2011. Results indicate a decline in total individuals and a drastic decline in seedlings from 2003 to 2011. However, two of the four plots showed an increase in non-reproductive individuals. Data from Kuhn and Rondeau 2015 revealed the lowest density of A. schmolliae individuals documented in six years of sampling. This is a sharp contrast to the previous year, 2013, when density levels were the highest recorded in their studies. In 2014, as in almost all of the other sampling years, there was no statistically significant difference in number of individuals in burned vs. unburned plots. The only exception was 2012. 

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

Intrinsic Vulnerability Comments: Restricted distribution. Other factors unknown.

Environmental Specificity: Unknown
Environmental Specificity Comments: Factors constraining range are not known. It appears to be absent on Wetherill Mesa despite the presence of similar soils to Chapin Mesa.

Other NatureServe Conservation Status Information

Distribution
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Global Range: Endemic to Montezuma County, Colorado. It is found in the vicinity of Chapin Mesa extending south approximately 6 miles into the Ute Mountain Ute Reservation. Estimated range is 18 square kilometers, calculated in 2008 by the Colorado Natural Heritage Program in GIS 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 Montezuma (08083)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
14 Mancos (14080107)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A perennial herb. Stems are 4-6 dm tall. Leaves are composed of linear leaflets. Yellowish-white or cream-colored flowers bloom in May, followed by leathery pods in June.
General Description: Herbaceous perennial plants, 4-6 dm tall. Leaves are composed of 11-20 linear leaflets. Uppermost leaflet is jointed to the the rachis. Flowers are white, about 2 cm long, and have black hairs on the calyx. Pods are about 4 cm in length, strigose, curved downward, and dorsiventrally compressed (Spackman et al. 1997).
Terrestrial Habitat(s): Forest/Woodland, Woodland - Conifer
Habitat Comments: Sandy and gravelly flats and terraces, among junipers and pinyon pines, on sandstone (Spackman et al. 1997).  Fire is a natural component of the habitat for this species.  Associated taxa include: Purshia tridentata, Amelanchier utahensis, Poa fendleriana, Achnatherum hymenoides, Penstemon linarioides, Quercus gambelii, Solidago petrodora, Opuntia polyacantha, Yucca baccata, Astragalus wingatanus, Lupinus amophilius, Eriogonum racemosum, Chrysopsis villosa, and Polygonum sawatchense. 


Sandy and gravelly flats and terraces, among junipers and pinyon pines, on sandstone (Spackman <i>et al. </i>1997). Fire is a natural component of the habitat for this species. Associated taxa include: <i>Purshia tridentata, Amelanchier utahensis, Poa fendleriana, Achnatherum hymenoides, Penstemon linarioides, Quercus gambelii, Solidago petrodora, Opuntia polyacantha, Yucca baccata, Astragalus wingatanus, Lupinus amophilius, Eriogonum racemosum, Chrysopsis villosa, and Polygonum sawatchense.

Economic Attributes
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Economically Important Genus: Y
Management Summary Not yet assessed
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Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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Excellent Viability: Size: 15,000 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: 2500 to 15,000 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 2500 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).
Date: 22Apr2015
Author: Handwerk, J.
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 05Sep2012
NatureServe Conservation Status Factors Author: Peterson, S.J., rev. C. Russell, rev. Spackman (1996), rev. Handwerk, J. (2006), rev. Neuhaus, K., J. Handwerk, and S. Panjabi (2006), rev. Handwerk, J. (2010), (2012), (2015)
Element Ecology & Life History Edition Date: 12May2010
Element Ecology & Life History Author(s): Parker, J. (2010), 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
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  • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.


  • Anderson, D.G. 2004. Final Report: Population Status Survey of Schmoll's Milkvetch (Astragalus schmolliae Porter). Prepared for the National Park Service, Mesa Verde National Park. The Colorado Natural Heritage Program, Fort Collins, CO.

  • Barneby, R.C. 1964. Atlas of North American Astragalus. 2 Vols. New York Botanical Garden, Bronx, New York. 1188 pp.

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

  • 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.

  • 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.

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

  • Peterson, J. S., B.C. Johnston, and W. Harmon. 1981. Astragalus microcymbus status report of 3 March 1981.

  • 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.

  • 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.

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