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NEWS RELEASE: June 8, 2011


Fremont County Rockcress Designated Candidate for Endangered Species Protection;

Protection for Gibbens’ Beardtongue, Precocious Milkvetch, Ross’ Bentgrass, and Yellowstone Sand Verbena is Not Warranted


  • Genevieve Skora 307.772,2374
  • Dan Blake: 307.772.2374
  • Leith Edgar: 303.236.4588

The U.S. Fish and Wildlife Service (Service) has completed a status review of five Wyoming plants.  We have determined that Fremont County rockcress (Boechera pusilla) warrants protection under the Endangered Species Act (Act); however, listing the plant is precluded by the need to address other high priority species.

We have also determined that Gibbens’ beardtongue, precocious milkvetch, Ross’ bentgrass, and Yellowstone sand verbena do not warrant protection under the Act because we found no factors that cause these species to be endangered or threatened.  We made these findings after a thorough review of all the available scientific and commercial information regarding the status of these species.

Fremont County rockcress is also called small rockcress and was formerly identified as Arabis pusilla.  This speciesis a perennial herb found only in the southern foothills of the Wind River Range, in Wyoming, on land administered by the Bureau of Land Management (BLM) Rock Springs Field Office.  There is only one known population of this species. 

We have not fully identified the nature of the threat or threats to the Fremont County rockcress,  but the reduced population numbers demonstrate some type of threat is present.  The threat may be connected with drought conditions, disease, or other factors.  Additionally, Fremont County rockcress may already be below the minimum viable population size for this species to persist. The flowering population in 2010 was 350 plants, down from a recorded high of approximately 900 individuals in 2003.

The Service will make a determination on the status of Fremont County rockcress as threatened or endangered when we do a proposed listing determination.  Currently, listing of Fremont County rockcress is precluded by higher listing priorities.  In the interim, the Service will add Fremont County rockcress to our list of candidate species and review its status annually.  The Service has assigned a Listing Priority Number of 8 to Fremont County rockcress based on our finding that the species faces threats that are of moderate magnitude and are imminent. 

Gibbens’ beardtongue (Penstemon gibbensii) is a perennial forb with bright blue tube-shaped flowers.  This species is a regional endemic that occurs near the intersection of the borders of Wyoming, Colorado, and Utah.  The majority of Gibbens’ beardtongue (77%) occurs on Federal and State land, with some on land managed by The Nature Conservancy that includes private land.  Gibbens’ beardtongue is listed as a BLM sensitive species.  As such, it is managed to promote its conservation and minimize the likelihood and need for listing under the Act.

Precocious milkvetch (Astragalus proimanthus) is a mat-forming, stemless, perennial herb that occurs only on the shale bluffs of the Henrys Fork River, near the town of McKinnon, Wyoming.  The majority of this species’ distribution is on land managed by the BLM (95%), with some occurrences on State and private lands.  Precocious milkvetch is also listed as a BLM sensitive species.  In addition, this species has been designated as a special status plant species and is included in an Area of Critical Environmental Concern that further protects it from surface disturbance or other activities that could adversely affect it or its habitat.

Ross’ bentgrass (Agrostis rossiae) is a small annual grass that grows as a dense clump.  This species is a regional endemic that grows on glacial deposits that border active geysers and hot springs in the west-central portion of Yellowstone National Park.  The National Park System is mandated with conserving the scenery, natural and historic objects, and the wildlife within its parks.  Additionally, the National Parks have mechanisms in place to control nonnative plants and ensure that visitors do not harm the plants located within the parks.

Yellowstone sand verbena (Abronia ammophila) is a low-growing, mat-forming perennial herb that is only found in Yellowstone National Park on the shores of Yellowstone Lake.  Yellowstone sand verbena occurs in four populations; however the majority of plants are located in one population.  Yellowstone sand verbena also receives the protections of the National Park System as described above.

We found no evidence that any factor affects Gibbens’ beardtongue, precocious milkvetch, Ross’ bentgrass, or Yellowstone sand verbena to a degree that these species would meet the definition of threatened or endangered under the Act.  Therefore, we determined listing Gibbens’ beardtongue, precocious milkvetch, Ross’ bentgrass, and Yellowstone sand verbena is not warranted at this time.  Because listing these four species is not warranted, we will take no further action with these species at this time.

While candidate species receive no statutory protection under the Act, inclusion on the candidate list promotes cooperative conservation efforts for these species.  Our ultimate goal, which is shared by many state wildlife agencies, private organizations and individuals, is to intervene and successfully address the needs of candidate species so that listing is no longer needed.

For example, we provide technical assistance and competitive matching grants to private landowners, states and territories undertaking conservation efforts on behalf of candidate species.  We also work with interested landowners to develop Candidate Conservation Agreements.  These voluntary agreements allow citizens to manage their property in ways that benefit candidate species, in some cases precluding the need to list the species.  These agreements can also be developed to provide regulatory certainty for landowners should the species become listed under the Act.

Addressing the needs of candidate species before the regulatory requirements of the Act come into play often allows greater management flexibility to stabilize or restore these species and their habitats.  In addition, as threats are reduced and populations are increased or stabilized, attention can be shifted to those candidate species in greatest need of the Act’s protective measures.

We made these determinations in response to a petition filed July 24, 2007, by Forest Guardians (now WildEarth Guardians) requesting that all full species occurring in our Mountain-Prairie Region ranked as G1 (critically imperiled) or G1G2 (critically imperiled or imperiled) by the organization NatureServe be listed as threatened or endangered under the Act.  The petition identified 206 species as petitioned entities, including the 5 species we address in this status review.  We completed an initial review of these species on August 18, 2009, and concluded that the petition contained substantial information supporting a full study of the status for these five species.  Today’s announcement constitutes our final action on this petition for these species.

A copy of the final rule and other information about Fremont County rockcress, Gibbens’ beardtongue, precocious milkvetch, Ross’ bentgrass, and Yellowstone sand verbena are available on the internet at http://www.fws.gov/mountain-prairie/species/plants/fivewyomingplants or by contacting the Wyoming Ecological Services Field Office, U.S. Fish and Wildlife Service, 5353 Yellowstone Road Suite 308A, Cheyenne, WY 82009, phone (307) 772–2374.  The final rule is published in today’s Federal Register.  Please submit any new information, materials, comments, or questions concerning this finding to the above address.

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people.  We are both a leader and a trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service.  For more information on our work and the people who make it happen, visit fws.gov.

 - FWS -


Last updated: April 10, 2015