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1 Posr-rrrlamarion /nresnyarion ' Despite the rebound in percent composition of annuals, 4 of the 8 test plots steadily increased in perennial composition from 1993 through 1995. with the other 4 still well above the 1993 ' abundances (Figure a). This appazent trend to~vazd an increase in perennials is encouraeing and indicates that the vegetation is progressing toward aself-sustaining permanent stand. Additionally, ' diversity has increased and baze ground has decreased over the 4-year period (Appeudix B). During the 1995 data collection. the reference plot was also sampled. All eight test plots had ' much higher total vegetative cover than the reference plot (Figure 2 and Appeudix B-3). However. all test plots had a lower percent perennial cover than the reference plot (Figure 4). Analysis of species composition reveals the almost complete absence of annuals (particularly ' cheatgrass and tumble mustard) from the undisturbed reference plot (Table 2). Also. the reference plot had a relatively high amount of shrub cover compared to the test plots. These results suggest that [he test plot vegetation community has not yet fully matured. ' The data indicate that soil cover depth does influence vegetative cover. Generally. for all three years of sampling of total vegetative cover, annual species cover, and perennial species cover ' (Figures 2, 3, and 4, respectively), the trends indicate that cover was highest on the 36-inch or 48-inch cover plots. Cover was also slightly higher on the north facing plots over the south facing plots. It is also reasonable to conclude that other factors such as aspect and moisture are ' controlling the abundance and distribution of vegetative cover. For the three years of cover sampling, sample adequacy was reached on all test plots within 10 ' or less transects. However, the reference plot was more variable, requiring 19 transects to reach adequacy (Appendix B-1). ' Herbaceous Production ' The two years of production data presented in Table 3 and Figures 5 through 7 illustrates the overall increase in production found in 1995. Productivity was extremely variable during both years of sampling. Sample adequacy was achieved only once on test plot SI in 1993 (Table 3). ' The number of quadrats needed to achieve adequacy was much higher than the l0 per plot sampled (Appendices C-1, C-2, C-3). ' Herbaceous production doubled from 1993 to 1995 except for test plots S2 and S3 (Figure 5 and Table 3). Production by annuals was also higher in 1995 than 1993 in all test plots (Figure 6). Field obsen~ations found that, as with vegetative cover. the annual cheatgrass and tumble mustard ' were the major contributing species in the increase. Above average spring and early summer precipitation in 1995 probably contributed to the increased production and may have even been the primary factor for the annuals' invasion. 1 1 1 ' _'J6-OTIWrg-rpi3 1a