CPC Plant Profile: Shivwits Milkvetch
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Plant Profile

Shivwits Milkvetch (Astragalus ampullarioides)

Photo Credit: Renee Van Buren
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Fabaceae
  • State: UT
  • Nature Serve ID: 135255
  • Date Inducted in National Collection: 09/01/2001

Astragalus ampullarioides is an extremely rare species comprising four small populations in Washington County, Utah (Van Buren and Harper 2003). The species is restricted to Chinle soils and was Federally listed as Endangered in September 2001. Significant portions of this species habitat is threatened with extinction by multiple threats. These threats include urban development, heavy grazing by cattle and rabbits, off-road vehicle use, and mineral exploration and development. Astragalus ampullarioides is a perennial, herbaceous plant with cream colored flowers that are produced in the spring. The U.S. Fish and Wildlife Service and Welsh recognize this entity at the full species level as A. ampullarioides (Welsh 1998). This taxon was originally described as a variety of Astragalus eremiticus. Later research demonstrated significant genetic differences (Stubben 1997) as well as morphological and ecological differences (Welsh 1998) to warrant full species status. This species resembles Astragalus ampullarius, but the caudex isnt as deeply buried and the stipules are distinct (UNPS 2003).

Participating Institutions
Updates
Nature Serve Biotics
  • 05/02/2017

Edaphic endemic with a very small range that occurs on one geological formation in Washington Co., Utah. There are seven extant populations with most of the potential habitat previously destroyed by urban development. More than 50 percent of known populations has been destroyed (from about 2000 to less than 1000 individuals). (Armstrong and Harper 1991, VanBuren 1992). Threats include development, trampling, grazing, and pollinator declines.

  • 01/01/2010

Habitat disturbance from urban development, off-road vehicles, grazing by cattle and rabbits, displacement by exotic weed species, mineral development clay quarry mining, and unauthorized waste disposal (USFWS 2000).

  • 01/01/2010

The four populations contain on average 1,000 individuals in a given year (Van Buren 2003).

  • 01/01/2010

Currently the USFWS is developing a recovery plan for this species. A seed bank study at Utah Valley State College is also currently underway.

  • 01/01/2010

Currently the USFWS is developing a recovery plan for this species. A seed bank study at Utah Valley State College is also currently underway.

  • 01/01/2010

(1) Fence perimeter of populations; (2) Conduct pollination biology studies to determine pollinators and breeding system of species; (3) Conduct genetic studies on all populations to manage for and address genetic diversity concerns; (4) Conduct competition studies to determine effects of alien species on seedling establishment.

  • 01/01/2010

Seed should be collected from existing populations and stored at established conservation seed programs. Existing populations should be monitored annually and seed should also be collected from newly-established individuals to increase the genetic diversity and gene pool for this species stored at conservation seed programs.

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Nomenclature
Taxon Astragalus ampullarioides
Authority (S.L. Welsh) S.L. Welsh
Family Fabaceae
CPC Number 10827
ITIS 820304
USDA ASAM14
Common Names SHEM Milkvetch | Shivwits | Shivwit's milkvetch | Shivwits milk-vetch | hermit milkvetch
Associated Scientific Names Astragalus ampullarioides | Astragalus eremiticus var. ampullarioides | Astragalus eremiticus var. malheurensis | Astragalus eremiticus var. spencianus | Astragalus malheurensis
Distribution Washington County, UtahLAND OWNERSHIP:Bureau of Land Management- St. George Field Office, National Park Service Zion N.P., Paiute Tribal Lands, State Trust Lands, and Private.Approximately 50
State Rank
State State Rank
Utah S1
Habitat

Astragalus ampullarioides is distributed on a narrow band of the exposed Chinle formation over a distance of about 40 km (25mi) near the city of St. George, Utah. A. ampullarioides is a narrowly distributed Mojave Desert endemic in warm desert shrub and pinyon-juniper communities. Associated native plant species include Dichlostemma pulchellum, Lotus humistratus, Gutierrezia microcephala,and Calochortus flexuosus. Most frequent species within monitoring plots include Bromus rubens, Bromus tectorum, Erodium cicutarium, and Dichelostemma pulchellum (Van Buren 1998).

Ecological Relationships

Astragalus ampullarioides is a tall member of the Fabaceae, with stems growing up to a height of 50 cm (20 inches). Each plant produces approximately 45 flowers on a single flowering stalk in the spring. Unlike many members of the Astragalus genus, A. ampullarioides is highly palatable to grazing animals (USFWS 2000). Individuals of this taxon appear to live 4-5 years, perhaps longer (Van Buren 1998). Population density of A. ampullarioides is correlated with precipitation with adult mortality affected by the previous years rainfall and seedling emergence affected by the current years rainfall (Van Buren and Harper 2003). The breeding system of this species is presently unknown. However, this species is visited and probably pollinated by bumblebees and anthophorid bees (Torti 2003).

Pollinators
Common Name Name in Text Association Type Source InteractionID

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