Cheatgrass - native plant community interactions in an invaded southwestern forest

Abstract

Invasions by nonnative plant species such as cheatgrass (Bromus tectorum) are a major concern in many ecosystems worldwide. When invasive nonnative species dominate a new ecosystem, they can alter biodiversity, species composition, nutrient cycles, disturbance regimes, and other ecosystem functions and processes. In 2003, cheatgrass rapidly spread through the Mt. Trumbull Ecosystem Restoration Project in the Uinkaret Mountains of northwest Arizona. In several areas, cheatgrass became the dominant herbaceous species, although native vegetation continued to dominate a substantial portion of the landscape. The three studies I present here examine the roles of disturbance, propagule pressure, competition, and resource availability on cheatgrass - native plant dynamics. The first study examines the susceptibility of remnant native vegetation to cheatgrass invasion, and persistence of the cheatgrass invasion in the presence of elevated disturbance through biomass removal and/or elevated propagule pressure through seed additions. Both cheatgrass- and native-dominated areas were persistent for three years after treatment. The second study monitored changes in plant species richness, composition, and distribution in invaded and non-invaded areas.

Citation

McGlone, Christopher M. 2010. Cheatgrass - native plant community interactions in an invaded southwestern forest. Flagstaff, AZ: Northern Arizona University. 133 p. Dissertation.