West Mojave Plan FEIR/S - Desert Managers Group

Using Dr. Berry’s same data, Table 3-13 shows the percent declines observed at eachof the study plots, the dates of the first and last surveys, and the elapsed time between thesurveys (in parenthesis). Study plots are shown in descending order of observed tortoisedecline, with the highest declines shown at the top and the lowest at the bottom.Table 3-13Percent Declines in Tortoise Numbers at Nine Permanent Study Plotsin the West Mojave Planning Area, 1979 - 1996STUDY PLOT FIRST - LAST SURVEY DATES PERCENT DECREASE(ELAPSED YEARS)Fremont Peak 1980 - 1993 (13) 93%DTNA Interior 1979 - 1996 (17) 91%DTNA IC Outside 1979 - 1993 (14) 84%Johnson Valley 1980 - 1994 (14) 77%DTNA IC Inside 1979 - 1993 (14) 74%Fremont Valley 1981 - 1991 (10) 72%Kramer Hills 1980 - 1995 (15) 69%Lucerne Valley 1980 - 1994 (14) 30%Stoddard Valley 1981 - 1991 (10) 5%These data indicate that tortoise declines have ranged from as much as 93% at theFremont Peak study plot to as little as 5% at the Stoddard Valley study plot. In the past, therehas been some criticism of extrapolating declines found at the study plots to surrounding areas.Tortoise sign count surveys conducted between 1998 and 2002 for the West Mojave Plan,however, have demonstrated that these regional declines indeed have occurred, and are notrestricted to the permanent study plots. Moreover, the pattern of decline recorded at Dr. Berry’sstudy plots mirrors the findings of the regional field surveys. Above average tortoise sign countsoccur in regions that encompass the three plots where declines were least severe (Kramer Hills,Lucerne Valley, and Stoddard Valley). The plots where tortoise declines were between 93% and72% (Fremont Peak down to Fremont Valley) occurred outside the above-average tortoise signcount polygons.3.3.2.4.2 Desert Tortoise Field SurveysMany types of focused desert tortoise surveys have been conducted:• Since 1990, “presence-absence” surveys have been required by cities and counties todetermine if tortoises would be adversely affected by a proposed project or land use.• Since 1990, “clearance” surveys have been authorized under Section 7 and Section10(a)(1)(B) of FESA to remove tortoises from harm’s way during otherwise lawfulactivities.• During 2001 and 2002, “distance sampling” surveys have been completed throughout thefour proposed DWMAs, which are intended, over a relatively long period of time (i.e., 30years), to estimate tortoise densities and population trends at the DWMA level.Chapter 3 3-78