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6 <br />Shrub density was estimated by counting the number of shrubs • <br />encountered within a 1.0 m= plot. Density was recorded by species. <br />The shrub had to be rooted in the plot to be counted. <br />Tree density was obtained by counting the number of trees and <br />saplings of each tree species occurring within a 50 mz (5 x 10 m) area. <br />Trees and saplings were counted separately, but both were included in <br />the total density measure. <br />Means (x) and standard deviations (s) were calculated for <br />total plant cover, litter and rock cover, plant-litter-rock cover, <br />bare ground, total production, total shrub density and total tree <br />density. These values were calculated for each affected area and <br />reference area. <br />Sample adequacy was calculated for cover and production <br />using the following standard formula: ,_~ <br />~ = z2 (sZ) <br />A d z <br />where n =number of samples <br />z = table value (for grassland z = 1.64; for shrubland z = 1.28) <br />s =standard deviation <br />z =mean of particular parameter <br />d =level of precision: grassland .10 <br />shrubland .20 <br />A standard number of samnles was taken--15 for cover, production <br />and density on the affected areas, and lOfor cover, production and density <br />on the reference areas--before sample adequacy v,as calculated. ;lddi- <br />tional cover or production samples were taken until sample <br /> <br />