Equilibrium theory predicts that following disturbance, ecosystem structure and function will eventually converge with those of undisturbed ecosystems that are not changing. This study tested this theory by comparing the structural characteristics of a sedge meadow recovering from disturbance by cattle grazing to that of a reference site, from 1977 to 1997 in Wisconsin. Both of these study sites changed structurally from 1977 to 1997, supporting the non-equilibrium theory. Seedlings of Cornus sericea were invading the grazed sedge meadows and the reference sedge meadow. Changes in the reference site were relatively minor over this time interval; certain species either increased or decreased in dominance. A few short-term species of the recovery sedge meadow, Aster lanceolatus, Calamagrostis canadensis, Poa compressa, Solidago altissima, and Verbena hastata, followed the tenets of the equilibrium theory, but became less apparent 4-9 years after cattle exclusion. This study suggests that the progression from sedge meadow to shrub dominated carr is linked to disturbance by cattle grazing and not strictly an outcome of succession. Ultimately, the shift from sedge meadow to shrub carr, in the aftermath of cattle grazing, may be permanent, and represent an example of non-equilibrium dynamics in succession.
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.