RT Journal Article SR Electronic T1 Effect of Pseudoroegneria spicata (bluebunch wheatgrass) Seeding Date on Establishment and Resistance to Invasion by Bromus tectorum (cheatgrass) JF Ecological Restoration FD University of Wisconsin Press SP 145 OP 152 DO 10.3368/er.38.3.145 VO 38 IS 3 A1 Harvey, Audrey J. A1 Simanonok, Stacy C. A1 Rew, Lisa J. A1 Prather, Timothy S. A1 Mangold, Jane M. YR 2020 UL http://er.uwpress.org/content/38/3/145.abstract AB Rangelands degraded by non-native annual grasses are commonly restored by integrating herbicide with fall seeding of native perennial grasses. Seeds are expected to remain dormant throughout winter and emerge in spring. However, restoration often fails due to annual grass seedlings out-competing seeded grasses because they emerge sooner and grow faster. At two sites in Montana, we tested eight seeding dates of Pseudoroegneria spicata to determine the effect on resistance to invasion by the annual grass Bromus tectorum. After one growing season, fall (November) and early spring (April) seeding resulted in larger P. spicata than later spring seeding (May) (829–1,180 tillers per m2 versus 349–561 tillers per m2) at one site, while seeding date had no effect on P. spicata at the second site. In the second season and after B. tectorum introduction, fall and early spring seeded P. spicata was more resistant to B. tectorum compared to late spring seeded. For example, B. tectorum was less dense (480 ± 101 tillers per m2) in P. spicata stands seeded 7 April than 12 May (943 ± 188 tillers per m2), and B. tectorum biomass was lower in fall-seeded stands (227 ± 81 g per m2) than stands seeded 12 May (533 ± 206 g per m2). Our results demonstrate that establishment and subsequent invasion resistance is enhanced by seeding native grasses from fall to early spring, presenting a wider timeframe for seeding than commonly practiced.