Jane Hendron, 760/431-9440 ext. 205
Second 12-Month Status Review Finds Plant Not Warranted for Delisting
Carlsbad, Calif. - The U.S. Fish and Wildlife Service (Service) announced today it has completed a second status review of Peirsons milk-vetch (Astragalus magdalenae var. peirsonii) and concluded the plant should remain listed as threatened under the Endangered Species Act (ESA). The Services 12-month status review will be published in the July 17, 2008, edition of the Federal Register.
In the U.S, the plants only known population is located in Imperial County, California, in the Algodones Dunes. Most of the Algodones Dunes is managed by the Bureau of Land Management (BLM) as part of the Imperial Sand Dunes Recreation Area (ISDRA).
We were originally petitioned by the American Sand Association (ASA) and other off-highway vehicle (OHV) groups to delist the plant in 2001. In 2004, we completed a 12-month status review of the 2001 petition and determined the plant should remain listed under the ESA.
The 2005 petition to delist the plant was also submitted by the ASA and other OHV groups, and asserted that based on additional data collection Peirson?s milk-vetch is more abundant than was reported in the 2001 petition, and that the plants population and reproductive capacity are so stable and strong as to warrant delisting. After determining the petition provided substantial information a second status review was initiated.
Based on our review of all information provided in the petition and in our files, additional research, and input from peer reviewers, we determined that Peirsons milk-vetch is threatened by habitat destruction and modification from OHV use; predation by beetles that likely exacerbates other existing threats; and inadequacy of existing regulatory mechanisms to protect the plant because of uncertainties regarding future management of the ISDRA. Although the petition asserted that the population of Peirsons milk-vetch is more abundant than in 2001, this claim cannot be supported by the available survey data due to differences in rainfall amounts, survey methodologies and variations in climatic conditions between the survey years.
The ISDRA is one of the most heavily used off-highway vehicle recreation areas in the U.S. Although more than 27,000 acres is a designated Wilderness Area permanently closed to OHV use, this area supports less than nine percent of the U.S. population of Peirsons milk-vetch. More than 65 percent of the plants population within the ISDRA is located in temporary closure areas. Depending upon future management decisions by BLM these closure areas could reopen to OHV use, leading to an estimated 41 percent reduction in the plants population.
Another aspect of the 2005 petition focused on the assertion that the seed bank for Peirsons milk-vetch is capable of sustaining the plant based on seed production. Information provided in the petition estimated that plants produce an average of 14 mature seeds per seed pod -- based on collections from 10 plants at a single site -- and that all perennial plants are reproductive. The Service conducted a survey in 2005 and sampled 416 seed pods collected from 78 different plants at different locations, and found an average of only 5.2 mature seeds per pod. Though there may be as many as 15-17 seeds and immature ovules in a pod, only mature seeds can contribute to the seed bank.
Additionally, seed germination and emergence generally occurs between October and late February when the ISDRA receives some of its heaviest OHV use. Studies have shown seedlings damaged by OHVs produce fewer flowers and seeds, and areas closed to OHV use have larger seed banks than areas that are open to OHV use.
The Service reaffirms its determination that the 1998 listing of Peirsons milk-vetch as threatened under the ESA was not made in error and that the plant should remain listed.
A copy of the finding and other information about Peirson?s milk-vetch will be available on the Internet at http://www.regulations.gov"> and at www.fws.gov/Carlsbad.
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 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 www.fws.gov">.