Establishment and 10-year persistence of plant materials at Curlew National Grassland in southern Idaho

Abstract

In 2010, 58 plant material accessions of 35 species of native and introduced grasses, forbs, and shrubs were outplanted in a replicated study at the Curlew National Grassland (CNG) in Oneida County in southern Idaho. Introduced bunchgrasses, Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski [Poaceae]), Siberian wheatgrass (Agropyron fragile (Roth) P. Candargy [Poaceae]), and meadow brome (Bromus biebersteinii Roem. & Schult. [Poaceae]), as well as early-successional native grass species including bottlebrush squirreltail (Elymus elymoides (Raf.) Swezey [Poaceae]) and slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners [Poaceae]), had exceptional establishment. After 10 y, many introduced grasses maintained high plant densities, while plant density of early-seral species such as bottlebrush squirreltail and slender wheatgrass had declined significantly, and late-seral grasses, especially those with rhizomatous growth, increased. Our results show several accessions of all plant groups to be well-suited to conditions at CNG and other semi-arid sites of the sagebrush steppe. Long-term data also suggest that including a diversity of species of multiple seral stages in restoration seed mixes could be beneficial to occupying available niches in space and time and lead to desirable restoration results.