For Immediate Release: September 9, 2005 CA-CDD-05-87
Contact: Doran Sanchez (951) 697-5220; or Jan Bedrosian (916) 978-4616

Peirson's Milk-vetch 2005 Monitoring Data Published for Imperial Sand Dunes

Monitoring data documenting the 2005 density and population of the Peirson's milk-vetch, a plant species listed as threatened under the Endangered Species Act (ESA) and found in the Imperial Sand Dunes Recreation Area (ISDRA) in eastern Imperial County, has been published by Bureau of Land Management (BLM).

Monitoring of the plant is a requirement of the Recreation Area Management Plan (RAMP) approved by BLM in May as specified in the Biological Opinion issued by the U.S. Fish and Wildlife Service (FWS) in compliance with the ESA. The data were collected from more than 500 transects spread throughout the 160,000 acre ISDRA within the area's seven management areas with habitat suitable for Peirson's milk-vetch. Contractors in three teams consisting of 36 technicians walked 3,098 kilometers (1,923 miles) between late winter 2004 and early spring of 2005, collecting data under the supervision of BLM botanists.

Under the most recent protocols, monitoring of the milk-vetch was initiated in 2003 under a pilot study and continued more intensively in 2004, with the new data adding a third year of intensive monitoring data about the species. This new data also tracks from other monitoring data compiled by BLM between 1998 and 2002.

The 2005 data is available on BLM's website at http://www.blm.gov/nhp/spotlight/state_info/highlights.htm.

According to the executive summary of the monitoring study, there were an estimated 1.8 million Peirson's milk-vetch plants in the seven management areas at the time of the survey as follows (from north to south):

-Mammoth Wash Management Area - 73,502 plants
-North Algodones Dunes Wilderness - 179,283 plants
-Gecko Management Area - 305,583 plants
-Glamis Management Area - 78,201 plants
-Adaptive Management Area - 660,131 plants
-Ogilby Management Area - 448,233 plants
-Buttercup Management Area - 86,143 plants

The study also states, "There were major differences between 2005 and the years 2003 and 2004…. The favorable 2004-2005 growing season resulted in much higher numbers of plants in spring 2005 than in either 2003 or 2004, and the onset of rains in October 2004 resulted in a high percentage of plants flowering at the time of the 2005 monitoring." The study also notes, "About 0.44% of the estimated total number of Peirson's milk-vetch plants showed evidence of OHV damage at the time of the survey." It also notes, "Only… (1.6%) of the Peirson's milk-vetch plants in 2005 were more than a year old…. This supports previous contentions that this species functions more like an annual than a perennial and that the majority of seeds in the seed bank are produced from current year plants in good rainfall years." The study concludes this data represents "the clearest picture yet of the distribution of Peirson's milk-vetch in the Algodones [Imperial] Dunes."

-BLM-

California Desert District Office - 22835 Calle San Juan De Los Lagos, Moreno Valley, California - (951) 697-5220