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Lorennro Canvon Mine ~ Vegemuort 7echnira! Reyort • Mapping of transects in the disturbance and reference areas was accomplished at a scale of 1:400. Preliminary transect locations were identified on the general vegetation map in areas where disturbance was proposed. A grid and random number table were used to randomly locate transect locations on the map and a compass was used to locate the transects in the field. Slight modifications were made in the field if the preliminary location of a transect did not fall within a single community type. A random numbers table was used to relocate the transect in the field to fall within one community type only. Reference area transect locations were located similarly to disturbance area transect locations. Point-intercept Cover Quantitative studies of community composition employed the widely used point-intercept methods. The technique is efficient and appropriate for plant communities at Lorencito Canyon, suitable for both large and small mosaics, and objective. At a minimum, fifteen transects were sampled in each community type present in each disturbance area and corresponding reference area or sufficient transects were sampled to reach sample adequacy. Vegetative community types occurring within the disturbance areas included oak/pinyon pine and grassland. Transects were located in homogeneous vegetation units. Ground cover was evaluated using the Cover-Point Optical Point Projection Device along each 50- • meter transect by sampling two points approximately one-meter apart for a total of 100-points per transect. Each sample point was determined by projecting the ocular sight vertically downward to the sample location on the transect and recording all "hits" as either litter, rock, bare ground, or vegetation by species. In treed communities, canopy cover was also evaluated by projecting the ocular sight vertically upward to the sample location above the transect and recording only vegetative "hits." Following the data collection at the minimum number of transects, statistics were run in the field to determine whether sample adequacy was achieved. Sample adequacy was determined using the Snedecor-Cochran sample adequacy formula. The formula is as follows: Nm;n = (t~sZ) divided by (dx)~ where: Nm;n = the minimum number of observations needed, t = the t-table value for a two-tailed t-test with (n-1) degrees of freedom at the 90% confidence level, s= = the sample variance, • Veg.476/December 9, 1996 2