West Mojave Plan FEIR/S - Desert Managers Group

Table 3-32 shows the relative abundance of perennial and annual plants, winterfat,hopsage, and saltbush observed during the 1998 Survey on the 102 sites with historic MGSrecords and the 208 additional sites within the known range. Numbers represent the number ofplants observed on a given (or average) transect.Table 3-32Comparisons Among Habitat Variables Observed Along 1998 Survey TransectsNUMBER OF PLANTSTransect Type102 WithMGS Records208 Without MGSRecordsPerennialPlantsRange: 3 to 21Mean: 9.8Range: 2 to 19Mean: 10.6AnnualPlants3 to 3819.57 to 4721.2Chapter 3 3-150Winterfat Hopsage Saltbush Hopsage &Winterfat0 to 458 0 to 164 0 to 463 1 to 164 / 1 to 45815.1 14.6 89.2 28.0 32.00 to 423 0 to 242 0 to 646 1 to 242 / 1 to 42323.3 21.0 82.2 36.0 40.0NUMBER (%) OF TRANSECTS WITH NO OCCURRENCES OF SPECIFIED PLANT102 With MGSRecords208 Without MGSRecordsN/A N/A 45(44%)N/A N/A 73(35%)38(37%)60(29%)51(50%)86(41%)24(23%)39(19%)These data suggest that the average numbers of winterfat and hopsage observed wereabout the same within each of the two transect categories (15.1 versus 14.6 and 23.3 versus21.0). The largest numbers of winterfat exceeded those of hopsage two times on 102 transects(211 and 458 for winterfat versus 164 for hopsage) and two times on 208 transects (367 and 423versus 242). This indicates, on average, that winterfat and hopsage may occur in similarnumbers on a regional scale, but that winterfat occasionally occurs in denser aggregations thanobserved for hopsage.In comparing the two data sets, relatively more winterfat and hopsage occurred on the208 transects than on the 102 surveyed at historic MGS locations. This is also reflected in therelatively lower percentages of the 208 transects where one or the other (or both) plants wereabsent. This is not clear evidence against the current hypothesis that these two plants (andprobably others) may be critically important to MGS survival. Far too many factors governMGS densities and distribution to fully understand the relationship between MGS and plantoccurrence. For example, there is no evidence that MGS was absent from the 208 transects,which were all within the range. With the exception of transects surveyed between Lancasterand Lucerne Valley, most transects occurred in suitable, potentially occupied habitats, wherethere have been recent and historic observations.In a memo dated 6 August 2002, Dr. Leitner indicated that 48 of these 310 transectsincluded occurrences of: (1) 100 or more winterfat, hopsage, or the two combined or (2) between50 and 99 of either hopsage or winterfat. He found that 33 of these 48 occurrences (69%) wereconcentrated in three specific areas: 12 (25%) in the Little Dixie Wash area, between the SierraNevada and Ridgecrest/Inyokern; 11 (23%) in the Cuddeback Dry Lake/Pilot Knob area; and 10(21%) in the Coolgardie Mesa/Superior Valley area). The remaining 15 transects with theconcentrations of these plants were generally scattered, with only five occurrences south ofHighway 58.