Goose Creek Milkvetch
Astragalus anserinus
NatureServe conservation status
Global (G-rank): G2?
State (S-rank): S2
Utah Wildlife Action Plan status
- SGCN
External links
General information
Astragalus anserinus is a candidate species for listing as Federal Threatened or Endangered and is known from a small range straddling the Utah-Idaho-Nevada border region. Goose Creek Milkvetch has bright purple flowers and fuzzy grey green leaves that form low growing whitish mats. This plant is a spectacular site to see when it blooms across the barren hillsides each spring in northwestern Utah.
Description
Astragalus anserinus is a candidate species for listing as Federal Threatened or Endangered and is known from a small range straddling the Utah-Idaho-Nevada border region. Goose Creek Milkvetch has bright purple flowers and fuzzy grey green leaves that form low growing whitish mats. This plant is a spectacular site to see when it blooms across the barren hillsides each spring in northwestern Utah.
Phenology
Flowers May to June
Diagnostic characteristics
Astragalus anserinus is often mistaken for Astragalus purshii, but can be distinguished by having smaller, purple flowers and less wooly leaves. Astragalus purshii is white flowered with a purple keel tip.
Species range
Locally endemic to a portion of the Goose Creek basin where the borders of Nevada, Idaho, and Utah join. Extreme northeastern Nevada in Elko County (with a disjunct occurrence 22 miles southwest in the Delano Mountains), Cassia County in Idaho, and extreme northwestern Utah in Box Elder County.
Threats or limiting factors
Primary threats include drought, introduced plant species, grazing, fire and post fire disking, and recreation. A variety of invasive plants occur within or close to populations of Goose Creek Milkvetch, these include desert madwort (Alyssum desertorum), crested wheatgrass (Agropyron cristatum), cheatgrass (Bromus tectorum), flixweed (Descurainia sophia), leafy spurge (Euphorbia esula), and halogeton (Halogeton glomeratus). Goose Creek Milkvetch populations have been invaded by cheatgrass (Bromus tectorum), leafy spurge (Euphorbia esula), and crested wheatgrass (Agropyron cristatum). These three invasive plants represent a high magnitude and imminent threat to Goose Creek milkvetch (USFWS 2014). Crested wheatgrass was included in post-fire revegetation seed mixes used after the 2007 wildfires, in areas where Goose Creek Milkvetch occurs (USFWS 2014). Continued invasion of exotic species will result in population decline, and failure of populations to rebound from declines due to various factors. Fire and post-fire disking have also caused declines in numbers of Goose Creek Milkvetch plants (USFWS 2014, Lewinsohn 2015). Cattle grazing may also threaten long-term viability by altering habitat indirectly through soil compaction, trail formation, and increased erosion. Trampling and construction of access roads and water tank facilities also impacts habitat. Cattle grazing also depresses pollinators that may be assisting Goose Creek Milkvetch reproduction by destroying potential and existing nest sites and by removing food resources. The open, relatively barren slopes of the habitat (especially near pipeline corridors) are threatened off-road vehicles (USFWS 2014).
Taxonomy
No, this species does not have taxonomic discrepancies