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The relative abundance of desert tortoises on the Nevada Test Site within ecological landform units

Technical Report ·
DOI:https://doi.org/10.2172/304054· OSTI ID:304054
 [1];  [2]; ;  [3]
  1. Bechtel National (United States)
  2. Science Applications International Corp. (United States)
  3. Bechtel Nevada (United States)
Sign-survey transects were sampled in 1996 to better determine the relative abundance of desert tortoises on the Nevada Test Site (NTS). These transects were sampled within ecological land-form units (ELUs), which are small, ecologically homogeneous units of land. Two-hundred and six ELUs were sampled by walking 332 transects totaling 889 kilometers (km). These ELUs covered 528 km{sup 2}. Two-hundred and eight-one sign were counted. An average of 0.32 sign was found per km walked. Seventy percent of the area sampled had a very low abundance of tortoises, 29% had a low abundance, and 1% had a moderate abundance. A revised map of the relative abundance of desert tortoise on the NTS is presented. Within the 1,330 km{sup 2} of desert tortoise habitat on the NTS, 49% is classified as having no tortoises or a very low abundance, 18% has a low or moderate abundance, 12% is unclassified land being used by the Yucca Mountain Site Characterization Project, and the remaining 21% still has an unknown abundance of desert tortoises. Based on the results of this work, the amount of tortoise habitat previously classified as having an unknown or low-moderate abundance, and on which clearance surveys and on-site monitoring was required, has been reduced by 20%.
Research Organization:
Bechtel Nevada, Inc., Las Vegas, NV (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC08-96NV11718
OSTI ID:
304054
Report Number(s):
DOE/NV/11718--245; ON: DE99001392
Country of Publication:
United States
Language:
English