title: Effects of nitrogen limitation on species replacement dynamics during early secondary succession on a semiarid sagebrush site.
abstract: A soil nitrogen (N) availability gradient was induced on a disturbed sagebrush site in northwestern Colorado by fertilizing with nitrogen (high available N), applying sucrose (low available N), and applying neither nitrogen nor sucrose (control). Species composition was studied for 3 years. At the end of the study, N concentration of aboveground tissue of 3 major species was determined. The rate of species replacement was most rapid on plots receiving the sucrose treatment and was slowest on plots receiving the N treatment. Early-seral dominats had greater tissue N concentrations when availability of the resource was high but lower tissue N concentrations when available soil N became limited. Midseral dominants displayed the opposite pattern. These results suggest that the supply of available soil N, and therefore the dynamics of N incorporation in perennial plant tissue, is a primary mechanism in controlling the rate of secondary succession within this semiarid ecosystem.
authors.affiliation: Department of Range Science, Colorado State University, 80523, Fort Collins, CO, USA.
authors.forename: Terry
authors.initials: T
authors.lastname: McLendon
authors.affiliation: Department of Range Science, Colorado State University, 80523, Fort Collins, CO, USA.
authors.forename: Edward F
authors.initials: EF
authors.lastname: Redente
keywords: Competition; Disturbance; Nitrogen; Shrubland; Succession