• Effects of Single and Sequential Defoliations on the Carbohydrate Reserves of Four Range Species

      Menke, J. W.; Trlica, M. J. (Society for Range Management, 1983-01-01)
      Four range species, fourwing saltbush (Atriplex canescens), antelope bitterbrush (Purshia tridentata), scarlet globemallow (Sphaeralcea coccinea), and blue grama (Bouteloua gracilis) were defoliated heavily (removing 90% of the foliage) at 1 of 5 phenological stages. In addition, other plants were clipped from 1 to 6 times at 3 phenological stages over a 2-year period. Total nonstructural carbohydrate (TNC) reserves of fourwing saltbush and antelope bitterbrush were most sensitive to a single defoliation at the seed-shatter phenological stage. Blue grama was affected most at the rapid growth stage, whereas scarlet globemallow was not significantly affected by any of the single defoliations. A single defoliation proved adequate for determination of the most sensitive season for defoliation. Antelope bitterbrush was affected more by 6 successive intense defoliations than were the other 3 species: scarlet globemallow < blue grama < fourwing saltbush. TNC reserve cycles were severely dampened in antelope bitterbrush, and less so in fourwing saltbush.