Conduct field work in order to improve population estimates for all age classes of desert tortoises

Under a $131,750 Cooperative Agreement awarded September 1, 2025, through December 31, 2025, the U.S. Fish and Wildlife Service (USFWS) Region 8 funded Lonesome Desert, LLC to conduct comprehensive field monitoring and data collection activities for desert tortoise population assessment in California's Mojave and Colorado Deserts. Through the Endangered Species Recovery Implementation program (CFDA 15.657), Lonesome Desert provided qualified surveyors and handlers to execute line distance sampling, capture-recapture plot surveys, and telemetry work designed to improve population estimates across all age classes of desert tortoises. The awardee's deliverables included staffing demographic plot surveys with experienced transect walkers maintaining 5- to 10-meter belt intervals, deploying up to four trained tortoise handlers for field processing, and collecting standardized field data submitted via paper and electronic formats provided by the USFWS Desert Tortoise Recovery Office.

Additionally, Lonesome Desert maintained ongoing telemetry tracking of radio-transmittered tortoises at two to three focal population sites throughout California on a monthly basis, including the scheduled replacement of existing transmitters. These monitoring and data collection activities directly supported the Range-Wide Monitoring Program's objective of describing the status and trends of the Mojave desert tortoise population in California under USFWS direction, with all coordination conducted in partnership with the USFWS Desert Tortoise Recovery Office and other cooperating entities.

The U.S. Fish and wildlife service desert tortoise recovery office and partners lonesome desert LLC are proposing activities through the range wide monitoring program to fulfill this goal. Members of lonesome desert have partnered with the USFWS dtro to conduct line distance sampling along with associated telemetry work and plot based surveys in the mojave and colorado deserts of california over the last two decades. Lonesome desert will carry out proposed monitoring and related activities for collection of data to describe status and trends of the mojave population of the desert tortoise where IT occurs in california under the direction of the USFWS dtro. This scope addresses completion of desert tortoise monitoring and desert tortoise habitat surveys in california. Tortoise densities are monitored primarily using capture recapture plot surveys and line distance sampling. These methods require data collection on transects and at telemetry sites. Lonesome desert will provide qualified desert tortoise surveyors for demographic plot surveys. Personnel will ideally consist of surveyors with multiple years of experience walking belt transects for desert tortoises at 5 to 10 M intervals. Lonesome desert will also provide up to four qualified desert tortoise handlers for processing tortoises found during plot surveys. Lonesome desert staff will maintain coordination with the USFWS dtro and other cooperators as needed. Lonesome desert will maintain the tracking of transmittered tortoises at two or three focal populations in california once monthly throughout the term of the task. Data will be collected and submitted on field data sheets as well as electronically using survey forms provided by the USFWS dtro. Each focal tortoise will be fitted with a transmitter and lonesome desert will complete scheduled replacement of the existing transmitter units during monthly location activities at each of the focal sites. Lonesome desert will attempt to add transmitters to new tortoises as needed to maintain 12 transmittered tortoises at each site. Lonesome desert will provide the necessary transmitter units as well as all equipment and materials to attach them to the focal tortoises. Survey start dates and locations will be identified in coordination with the USFWS dtro based on activity periods of desert tortoises and in accordance with range wide monitoring needs. Demographic plot surveys will occur during the fall active season for the desert tortoise. Focal population maintenance will occur monthly for the duration of the year.