Astragalus perianus

Astragalus perianus is a perennial forb occurring on tertiary igneous gravels in alpine tundra, spruce-fir, and (rarely) sagebrush stands of the western United States, in Beaver, Garfield, Iron, Kane, Piute, and Sevier counties, Utah. It was once considered to be very rare or (possibly) extirpated throughout its range, but surveys conducted in the mid to late 1980s located twelve total populations containing approximately 300,000 individuals. It was delisted from the Federal List of Endangered and Threatened Plants in 1989. There are currently nineteen estimated occurrences, which are threatened by habitat degradation due to grazing, non-native mountain goats, wildfire, drought, recreation, and road maintenance. Surveys are needed to assess the current status of threats, site conditions, and abundance of plants.

Astragalus perianus occurs in the western United States, where it is endemic to south-central Utah (FNA 2023). Specifically, it is a Southern-Plateaus endemic of the Tushar Mountains and Sevier-Paunsaugunt and Markagunt Plateaus in Beaver, Garfield, Iron, Kane, Piute, and Sevier counties (Welsh et al. 2015). Range extent was calculated using data from the Utah Rare Plant Database (2024), excluding observations over 40 years old (UNHP 2024).

By applying a 2 km separation distance to herbarium records documented between 1994 and 2025, it is estimated that there are eleven occurrences rangewide (RARECAT 2025, SEINet 2025). However, the Utah Natural Heritage Program estimates that there are nineteen occurrences using population location data from the Utah Rare Plant Database (2024) and applying the same separation distance (UNHP 2024).

Threats were compiled using observations and notes from the Utah Rare Plant Database (2024) and Utah Geospatial Resource Center data (2024). Severity of impacts are not well known so ranges are provided where appropriate. The primarily threats to Astragalus perianus are habitat degradation due to grazing, fire, drought, recreation, and road maintenance (UNHP 2024).

All occurrences are located within grazing allotments, and many are also within mountain goat habitat. Mountain goats are non-native to the region, and were introduced to the Tushar Mountains by the State of Utah for trophy hunters (Alexander 2016, UNPS 2025). Many occurrences located on US Forest Service lands in the Dixie National Forest have burned (UNHP 2024). Fire has impacted some occurrences, and this risk is likely to increase as tree mortality has increased in Utah's forests due to widespread damage largely by spruce and bark beetles. Most occurrences are located near roads. Recreational use of habitat, such as foot traffic, dispersed camping, and off-road vehicles may pose a threat to some populations. As the human population grows in areas within easy access to habitat and as recreational use increases, the impacts may become more significant. Drought and climate change are also threats likely impacting this species throughout its range (Wrobleski et al. 2023).