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12 <br />favored by shallow topsoil. Smooth brome has most likely responded <br />• to the increased soil moisture and nutrients available on the <br />deeper soils while cicer milkvetch and Kentucky bluegrass may be <br />responding to decreased competition on the shallower soils. <br />After 10 years smooth brome dominated all treatments and <br />accounted for over 41$ of the relative biomass when averaged over <br />all four topsoil depths. Two subdominants, giant wildrye (Elvmus <br />cinereus) and cicer milkvetch accounted for an additional 27$ of <br />the relative biomass (16~ and 11~, respectively). Three Aaropyron <br />species (A. smithii, intermedium, and cristatum) added an <br />additional 22$ resulting in a total of 90$ of the relative biomass <br />of the topsoil treatments being produced by these six species. <br />Canopy Cover <br />• Total canopy cover ranged from 50 to 56~ across the four <br />topsoil depths with no consistent trends and nc significant <br />differences among treatments (Figure 3). There were differences at <br />the lifeform level with the three deepest topsoil depths (30, 45 <br />and 60 cm) supporting significantly more perennial grass cover than <br />the shallowest depth of 15 cm. Perennial forb canopy cover on the <br />other hand was significantly greater on 15 and 30 cm when compared <br />to 45 and 60 cm. Shrub cover was virtually non-existent on 45 and <br />60 cm and made up a very small portion of the total cover on the 15 <br />and 30 cm topsoil treatments. <br />Number of Species <br />The number of shrubs across the topsoil treatments was <br />• inversely proportional to depth in 1990. As depth increased the <br />