Turner et al. hypothesized that overcompensation most likely occurs in previously ungrazed tallgrass prairie as a result of stored photosynthate. In a 3-year experiment, the authors found that defoliation history largely controlled whether or not defoliated plants overcompensated for tissue removal. Plants on chronically grazed sites only compensated for foliage removed by grazers. They found that production on plots mowed 1-year prior was similar to sites that had been grazed long-term. Without prior mowing, however, aboveground production was 13-61% higher. On long-term grazed sites, production did not differ after 2-years of rest from sites grazed at a range of intensity. Current mowing regime was more important than mowing history in determining nitrogen concentrations except very early in the growing season. Effects of grazing and mowing were inconsistent, but frequent mowing appeared to limit accumulations of belowground N reserves and biomass. Under chronic grazing or mowing, vegetation is prevented from maintaining high nutrient and water uptake capacity and accumulating reserves that allow overcompensation responses.
Citations and enhanced abstracts for journals articles and documents focused on rangeland ecology and management. RSIS is a collaboration between Montana State University, University of Idaho, and University of Wyoming.