Indaziflam controls nonnative <i>Alyssum</i> spp. but negatively affects native forbs in sagebrush steppe

Abstract Nonnative plant invasions can have devastating effects on native communities; conversely, management efforts nontarget and deleterious impacts desirable plants. In the arid sagebrush steppe rangelands of western United States, nonnative winter annual species affect forage production biodiversity. One method proposed to control these is suppress soil seedbank using preemergent herbicide indaziflam. Our goal was evaluate efficacy indaziflam mustards ( Alyssum spp.) understand potential diverse mountain communities within Yellowstone National Park. Six sites were established along an elevation gradient (1,615 2,437 m), each with high low spp. infestations. We applied 63g ai ha ?1 in late summer 2018 evaluated community cover situ for 2 yr after treatment emergence forb from ex situ. Indaziflam highly effective at controlling yr. Richness Shannon’s diversity significantly lower sprayed plots than control, both decreased gradient. These reductions due a decrease perennial forbs plots; graminoids not affected. Overall, aboveground composition negatively impacted by indaziflam, strongest that rely regeneration seedbank. The this should be beyond length our study time; however, we conclude likely reserved use areas are severely invaded seedbanks composed nondesirable rather diverse, communities.