Site Characteristics Associated with Nuttall's and Weeping Alkaligrass in Northeastern Oregon

Abstract

Abstract Two species of alkaligrass, Nuttall's alkaligrass (Puccinellia nuttalliana [Schult.] Hitch.), a native, and weeping alkaligrass (Puccinella distans [Jacq.] Parl.), an introduced species from Eurasia, are found within semi-arid regions of the United States. Recently, land managers have become concerned over the ability of these two species to colonize a wide array of soil types, but have not been able to predict which sites might be at risk of invasion. Paired plots comparing site characteristics of infested versus very close, yet uninfested sites were sampled throughout the Grande Ronde Valley, northeastern Oregon. The results of this study indicate that Nuttall's alkaligrass was most commonly associated with sodic soils (73%), whereas 85% of the sites infested with weeping alkaligrass were agriculturally ‘normal’ sites. In general, Nuttall's alkaligrass was positively associated with sodium; whereas, for weeping alkaligrass, competing vegetation was the only factor affecting establishment and ab...