Asclepias welshii - N.& P. Holmgren
Welsh's Milkweed
Other Common Names: Welsh's milkweed
Taxonomic Status: Accepted
Related ITIS Name(s): Asclepias welshii N.& P. Holmgren (TSN 30325)
Unique Identifier: ELEMENT_GLOBAL.2.146639
Element Code: PDASC02290
Informal Taxonomy: Plants, Vascular - Flowering Plants - Milkweed Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Gentianales Asclepiadaceae Asclepias
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: Asclepias welshii
Conservation Status
Help

NatureServe Status

Global Status: G1
Global Status Last Reviewed: 21Oct2013
Global Status Last Changed: 29Nov1984
Ranking Methodology Used: Ranked by calculator
Rounded Global Status: G1 - Critically Imperiled
Reasons: Known from only six population areas with a total of approximately 20,000 above-ground stems (the number of genetic individuals is unknown). The known range includes Kane County, Utah, BLM land in Coconino County, Arizona, and Navajo Nation lands in Arizona (Navajo, Apache, and Coconino counties). The two Utah occurrences face the greatest threats, with parts of the species' very fragile sand dune habitat impacted primarily by off-road vehicle activity. The two Navajo Nation occurrences are smaller, but are relatively remote and are believed to have good to excellent viability. The two occupied areas on BLM land in Arizona are relatively remote, and not affected by ORV disturbance.
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 Arizona (S1), Navajo Nation (S1), Utah (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LT: Listed threatened (28Oct1987)
Comments on USESA: Asclepias welshii was proposed threatened on June 6, 1984 and determined threatened on October 28, 1987.
U.S. Fish & Wildlife Service Lead Region: R6 - Rocky Mountain

NatureServe Global Conservation Status Factors

Range Extent Comments: Occurs on the Coral Pink Sand Dunes and the Sand Hills 8 miles northeast of the Dunes, both in Kane County, Utah. In Arizona, several disjunct populations occur in Coconino County including the Paria Canyon-Vermilion Cliffs area near and along the border with Utah, the Ferry swale area near Thousand Pockets, sand dunes SE of Preston Mesa (N of Tuba City on the Navajo Nation - discovered 2002), and a second recently discovered (2001) population on the Navajo Nation occurring along Comb Ridge near Little Capitan Valley, extending from Navajo county just into Apache County (S of Monument Valley).

Area of Occupancy: 6-25 4-km2 grid cells
Area of Occupancy Comments: Total occupied habitat in Arizona and Utah is around 6.5 sq km, with the majority found in Arizona (6.06 sq km).

Number of Occurrences: 1 - 5
Number of Occurrences Comments: Six general areas known in both Arizona and Utah, 2 in Utah (Kane Co.) and 4 in Arizona. Arizona populations include BLM Paria Canyon Wilderness in Coconino Co., Ferry Swale area S of Utah border, and the recently discovered populations on the Navajo Nation in Arizona (Coconino, Navajo and Apache Cos.). The Navajo Nation populations were discovered in 2001 (re-visited 2002).

The species was surveyed for extensively on the Navajo Nation. Some additional populations may occur N of Tuba City. Both Wendy Hodgson and Lee Hughes indicate that more surveys are needed in proper habitat including Echo Cliffs. (Laurenzi and Spence 2012).

Population Size Comments: Known from a total of approximately 20,000 above-ground stems (the number of genetic individuals is unknown). One population on the Navajo Nation has at least several hundred stems and the other population is small with around 100 stems. In 1987 the populations in Utah numbered about 10,000 stems on the Coral Pink Sand Dunes and about 500 stems growing in the Sand Hills northeast of the Coral Pink Sand Dunes. In 1992, the populations on the Coral Pink Sand Dunes numbered 12,000 stems, while during the last census in 2002, about 72,000 stems were observed. By comparison, approximately 8500 were known in 1984.

Number of Occurrences with Good Viability/Integrity: Very few (1-3)
Viability/Integrity Comments: The Navajo Nation populations were noted to have good to excellent viability. Viability of the other Arizona occurrences, along with the Utah populations has not been assessed.

Overall Threat Impact: High
Overall Threat Impact Comments: In Utah, thousands of people visit the state park area for OHV, camping, hiking, etc.; livestock grazing is also a threat. On the Navajo Nation in Arizona, the main threat is grazing, although no immediate impacts have been observed; there are no issues with OHV traffic at this time. Likewise, the BLM Ferry Swale and Paria Canyon-Vermillion Cliff populations (Paria Wilderness Area) do not show any immediate impacts and are protected from OHV use, and livestock grazing.

The more immediate threats would be a small occupied geographically area, drought, and undisturbed dunes. This species prefers some amount of disturbance whether by wind, or OHV use, however, the age class observed is generally primary or secondary in areas with OHV use (Kneller 2002). More mature stems tend to be observed in those areas with natural disturbance such as wind (Kneller 2002). The populations on BLM land in Arizona are not affected by the light grazing that occurs there. Light livestock activity occurs below the dunes, and none of the plants were eaten or utilized by livestock (Hughes, 2009).

Short-term Trend: Decline of 10-30%
Short-term Trend Comments: Some population decline has been observed over the past few years in the Sand Hills population in Utah (Kneller 2002), however, since this is a rhizomatous plant, stem number does not necessarily equate to plant number. An ongoing drought in the area (since late 1990s) could be affecting the stem number in these populations.

In 1992, the estimate population for the Coral Pink Sand Dunes under Utah State Park management, was about 12,500 stems; the area managed by the BLM was not estimated. The other populations ranged in number from only a few to around one thousand stems, per census conducted by Franklin in 1992 and Lee Hughes of the Arizona Strip. In 2002 (Kneller), the entire Coral Pink Sand Dune was surveyed, with a total of 71,491 stems counted. Of these 16,133 (22.5%) were primary stems, 20,936 (29%) were secondary stems, and 34,422 (48%) were mature stems.

Both recently discovered (2001 & 2002) Navajo Nation occurrences seem stable, although no monitoring is presently ongoing.

Breakdown of population fluctuations:

1) Coral Pink Sand Dunes (UT): Low of about 5340 stems in 1980 to a high of 71,491 stems in 2002.
2) Sand Hills (UT): High of 574 stems in 1980 to a low of about 300 stems in 2002.
3) Pine Hollow Canyon UT or Wave/Stateline AZ: At least 240 stems observed in 1989 with a high of 566 stems in 1990, down to 14 stems counted in 2008.
4) Coyote Buttes (AZ): About 558 stems 1992 (no survey reports since).
5) Paria Plateau - Ferry Swale (AZ): About 166 stems observed in 1992 down to 23 plants in 2007 and none observed in 2008 (Hughes 2009).
6) Sand Cove (AZ): 16 Stems observed in 1989 and again in 1997.
7) Cottonwood Cove (AZ): About 246 stems observed in 1992 (not surveyed for since then).
8) Comb Ridge (near Little Capitan Valley - AZ): 100s observed over a large area in 2001 & 2002.
9) SE of Preston Mesa, ca. 12 miles N of Tuba City (AZ): About 45-50 stems discovered in 2002.

BLM populations in Arizona showing reduction due to competition with invading plants (Hughes 2009).

Long-term Trend: Unknown

Intrinsic Vulnerability Comments: Fragile nature of the habitat, easily degraded by surface disturbance, and movement of sand by wind when disturbed. However, note that the Navajo Nation populations are remote and difficult to access.

Environmental Specificity: Narrow. Specialist or community with key requirements common.
Environmental Specificity Comments: Predominately a plant of open red sand dunes of the Navajo Sandstone in extreme northern Arizona and southern Utah. It is found in sagebrush, juniper, and ponderosa pine communities at elevations ranging from 5,059 to 6,538 feet (1542 to 1993 meters).

Other NatureServe Conservation Status Information

Distribution
Help
Global Range: Occurs on the Coral Pink Sand Dunes and the Sand Hills 8 miles northeast of the Dunes, both in Kane County, Utah. In Arizona, several disjunct populations occur in Coconino County including the Paria Canyon-Vermilion Cliffs area near and along the border with Utah, the Ferry swale area near Thousand Pockets, sand dunes SE of Preston Mesa (N of Tuba City on the Navajo Nation - discovered 2002), and a second recently discovered (2001) population on the Navajo Nation occurring along Comb Ridge near Little Capitan Valley, extending from Navajo county just into Apache County (S of Monument Valley).

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 AZ, NN, UT

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Apache (04001), Coconino (04005), Navajo (04017)
UT Kane (49025)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
14 Lower Lake Powell (14070006)+, Paria (14070007)+, Chinle (14080204)+, Lower San Juan (14080205)+
15 Kanab (15010003)+, Moenkopi Wash (15020018)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Help
Basic Description: A stout, rhizomatous perennial herb, 2.5-10 dm tall. Produces globular clusters of flowers that are cream-colored with pink-tinged centers. The plants produce milky juice.
Technical Description: See Welsh et al. (1987).
Duration: PERENNIAL
Ecology Comments: Asclepias welshii is adapted to the naturally unstable drifting sands of the Coral Pink Sand Dunes and is a significant component of the flora of the Dunes. It is a colonizer of the unvegetated dunes in the sequence of plant succession on the Dunes.
Terrestrial Habitat(s): Forest/Woodland, Sand/dune, Shrubland/chaparral, Woodland - Conifer
Habitat Comments: Coral Pink sand dunes in sagebrush, juniper, and ponderosa pine communities at 1700 to 1900 meters. Occupies both the crest and lee slopes of dunes, adjusting readily to changes in depth of the sand. (Welsh et al. 1993)
Economic Attributes
Help
Economically Important Genus: Y
Management Summary Not yet assessed
Help
Population/Occurrence Delineation Not yet assessed
Help
Population/Occurrence Viability
Help
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
Help
Authors/Contributors
Help
NatureServe Conservation Status Factors Edition Date: 11Jun1987
NatureServe Conservation Status Factors Author: Roth, E., rev. D. Atwood, rev. B. Franklin (1996), rev. D. Roth/K. Gravuer (2006), rev. S Schuetze (2012)
Element Ecology & Life History Edition Date: 27Sep1990

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
  • 100th Congress. 1988. Endangered Species Act of 1973, appropriations authorization for fiscal years 1988-1992. Public Law 100-478-October 7, 1988 102 STAT.2307-102 STAT.2323.

  • Anderson, J. [1977-8]. Several plants species lists from BLM Cedar City District. Unpaginated [10 pp.].

  • Anderson, John. 1980. Study on Asclepias welshii on the Coral Pink Sand Dunes and Sand Hills. Cedar City District, Bureau of Land Management. Unpaginated ( 5 pp.).

  • Armstrong, L. 1993. Correspondence of December 17 to Ben Franklin.

  • Armstrong, L. 1993. Informal memorandum of March 8, 1993: Asclepias welshii recovery meeting.

  • Bringherst, Royce. 1990. Welsh's milkweed management plan (DRAFT). Coral Pink Sand Dunes State Park. Utah Department of Natural Resources. 12 pp.

  • Division of Parks and Recreation. 1985. Draft general management plan, Coral Pink Sand Dunes State Park. Utah Department of Natural Resources, Division of Parks and Recreation. 24 pp.

  • England, J. L. 1989. Memorandum, Fish and Wildlife Service.

  • England, L. 1986. Memorandum of December 4 to Asclepias welshii files.

  • Franklin, M.A. 1993. Survey report on Asclepias welshii N. Holmgren and P. Holmgren. 1992. Section Six Agreement, Utah Dept. Natural Resources, Utah Natural Heritage Program, U.S. Fish and Wildlife Service Ecological Service. Unpublished report on file Utah Natural Heritage Program, Salt Lake City. 6 pp. + appendices.

  • Holmgren, N. H., and P. K. Holmgren. 1979. A new species of Asclepias (Asclepiadaceae) from Utah. Brittonia 31(1): 110-114.

  • 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.

  • Lamb, G.W. 1990. Letter of October 30 to Sue Rutman of the U.S. Fish and Wildlife Service. BLM.

  • Letters. 1984. Concerning Asclepias welshii proposal to list.

  • Lunceford, B. 1988. Report. Welsh's milkweed marked plot monitoring studies. Kanab Resource Area, Bureau of Land Management. Unpaginated (3 pp.).

  • Lunceford, B.R. 1990. Welsh's Milkweed - Coyote Buttes Population Report from the 06-11-90 Study.

  • Lunsford, B. 1984. Maps of "T & E and sensitive plants in the Kanab Resource Area [BLM]." 1 p. + 2 maps.

  • Palmer, B. 1989. A Study of Welch's Milkweed Asclepias welshii) on the Coral Pink Sand Dunes. Bio. Dept. Southern Utah State College.

  • Palmer, B. C. 1993. Studies on Asclepias welshii, 1992. Report to the Bureau of Land Management. Brent Palmer Consulting. Unpaginated (19 pp.).

  • Palmer, B. C. 1991. Studies on Asclepias welshii, 1990-91 - A Continuation. Unpaginated (4 pp.).

  • Rowley, R. 1984. Kanab Resource Area, BLM. Letter to Dr. James L. Miller, USFWS, Denver, CO.

  • Rutman, S. 1992. Handbook of Arizona's endangered, threatened, and candidate plants. U.S. Fish and Wildlife Service, Phoenix, Arizona.

  • U. S. Fish and Wildlife Service. 1984. Proposal to determine Asclepias welshii (Welsh's milkweed) to be an endangered species. Federal Register 49(110): 23399-23401.

  • U.S. Fish and Wildlife Service (USFWS). 1984. Endangered and Threatened wildlife and plants; public hearing and reopening of comment period on proposed Endangered with Critical Habitat Status for Asclepias welshii (Welsh's Milkweed). Proposed rule; notice of public hearing, and reopening of comment period. Federal Register. 49(172): 34879.

  • U.S. Fish and Wildlife Service (USFWS). 1987. Endangered and threatened wildlife and plants; final rule determining Asclepias welshii (Welsh's Milkweed) to be a threatened species with critical habitat. Final Rule. Dated: October 28, 1987. Federal Register 52(208):41435-41441.

  • U.S. Fish and Wildlife Service (USFWS). 1992. Welsh's milkweed (Asclepias welshii) recovery plan. U.S. Fish and Wildlife Service, Denver, Colorado. 19 pp.

  • U.S. Fish and Wildlife Service. 1987. Final rule determining Asclepias welshii (Welsh's milkweed) to be a threatened species with critical habitat. Federal Register 52(208): 41435-41441.

  • USBLM. [1979]. Lists I, II, and III, i.e., threatened, endangered, and sensitive plant species. Cedar City District. Unpaginated (6 pp.) + map.

  • Van Pelt, Nicholas Sheridan. 1982. Coral Pink Sand Dunes (BLM); photos of Asclepias welshii and habitat. 2 pp.

  • Welsh, S. L., and K. H. Thorne. 1992. Report of Bureau of Land Management sensitive plant species: western Kane County, Utah. ?? pp.

  • Welsh, S. L., and K. H. Thorne. 1993. Report of Bureau of Land Management sensitive plant species: western Kane County, Utah. 49 pp.

  • Welsh, S.L., N.D. Atwood, L.C. Higgins, and S. Goodrich, eds. 1987. A Utah Flora. Great Basin Naturalist Memoir 9, Brigham Young University, Provo, Utah. 894 pp.

  • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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.