West Mojave Plan FEIR/S - Desert Managers Group

When data for the three lowest sign count categories (i.e., 0 to 8) are combined, a total of140 older transects (66% of 213) and 3,101 newer transects (92% of 3,362) were included.When data for the three highest categories (9 to 50) are combined, a total of 73 older (34%) and261 newer (8%) transects were included. One sees that there has been a shift in the abundanceof observed tortoise sign, with relatively few sign on proportionately more transects recentlysurveyed, corresponding to relatively more sign on proportionately more transects surveyed 20years ago. In other words, there has been a proportional decline in the abundance of tortoise signobserved on transects between 1980 and 2002, indicating a decline in the abundance of tortoisesbetween 1980 and 2002 (see Krzysik 2002a, b, c).Regions of Higher and Lower Tortoise Concentrations: Regions within the DWMAswere identified relative to above average (higher density) and below average (lower density) signcounts. Polygons were established to encompass all areas meeting two criteria. The two criteriaincluded: (1) There must be at least four contiguous square miles of above-average tortoise signbefore a polygon could be established; and, (2) polygon boundaries must not span more than onelinear mile not surveyed or having below-average sign counts. While this approach eliminatedsubjectivity from delineating polygon boundaries, it also resulted in encompassing some squaremiles where there were no data or the sign counts were lower than average.The results of this analysis are depicted in Map 3-8, and are displayed in Table 3-15.Three regions were identified in the Fremont-Kramer DWMA, seven in the Superior-CroneseDWMA, and five in the Ord-Rodman DWMA that support above-average occurrences oftortoise sign (and therefore tortoises; see Krzysik 2002a, b, c). None was found in the PintoMountain DWMA.Table 3-15Above-Average Tortoise Sign Counts ObservedIn Proposed DWMAs between 1998 and 2001DWMA SIZE AND %PROPOSED DWMA NUMBER OFABOVE-AVERAGEPOLYGONSSIGN COUNTS 8 ABOVE-AVERAGEFremont-Kramer 3 142 mi 2 779 mi 2 (18%)Superior-Cronese 7 147 980 (15%)Ord-Rodman 5 69 388 (18%)Pinto Mtn. 0 0 173 (0%)TOTAL 15 258 2,320 (15%)Fremont-Kramer DWMA: There are three tortoise concentration areas on about 142 mi 2 ,comprising about 18% of the 779 mi 2 Fremont-Kramer DWMA, which are shown on Map 3-8.Two of the three tortoise concentration areas occur mostly south of Highway 58, and the thirdone occurs in a 9 mi 2 area north of Highway 58, near the northwest corner of Harper Dry Lake.8In using the two rules to establish polygons, higher density tortoise areas included some square miles of lowerdensities and those that were not surveyed, as depicted on Map 3-7. However, only those square miles supportinghigher sign counts within the polygons are included in the tallies shown in the table. “Above-average” or “higherdensity” areas were derived by excluding all transects with no sign and determining the average of the remainingvalues. In this comparison, only transects surveyed in DWMAs are included. As such, “above-average”transects/square miles are actually “average and above” transects found in DWMAs.Chapter 3 3-87