Since Euro-American settlement of the region, biological diversity of the northern Great Plains has been adversely affected, mainly by agricultural conversion. The role of invasive plants in degradation of remaining prairies has gained attention in recent years but remains poorly understood. Floristic composition of US Fish and Wildlife Service (Service) prairies is significantly altered, mainly by invasion of smooth brome (Bromus inermis Leyss.), Kentucky bluegrass (Poa pratensis L.), and woody vegetation. We measured floristic composition of about 90 000 ha of Service-owned mixed-grass and tallgrass prairie in North Dakota, South Dakota, and northeastern Montana. Our primary objective was to identify factors associated with greater native grass-forb plant assemblages, while conversely identifying features more aligned with Kentucky bluegrass, smooth brome, and low shrub invasion. Service-owned prairies had a higher frequency of native grass-forb farther from habitat edges, such as cropland boundaries and roads, and on harsher ecological sites composed of poorer soils, steeper slopes, or with southern and western exposures. Kentucky bluegrass, smooth brome, and low shrubs differed in their respective responses to explanatory variables we considered and also reportedly differ in response to management actions such as fire and grazing. Therefore, prairie managers can expect significant challenges during restoration management in cases where two or more of these invaders occur. By understanding patterns of invasion related to edaphic, edge, and landscape features, prairie restorationists can focus on areas where the probability of restoration success is greater and better understand how these features might influence restoration success or failure.

自从该地区的欧洲人定居以来，大平原北部的生物多样性受到了不利影响，主要是受到农业转产的影响。近年来，入侵植物在剩余大草原的降解中的作用受到关注，但仍知之甚少。美国鱼类和野生动物服务局（服务部）草原的植物组成发生了显着变化，主要是由于入侵了光滑的溴（Bromus inermis Leyss。），肯塔基州的蓝草（Poa pratensis）L.）和木质植被。我们测量了北达科他州，南达科他州和蒙大拿州东北部约9万公顷服务业拥有的混合草和高草草原的植物区系组成。我们的主要目标是确定与较大的原生草草植物组合相关的因素，而相反地，确定与肯塔基州早熟禾，平滑溴和低灌木入侵更一致的特征。拥有服务的草原在远离栖息地边缘（例如农田边界和道路）以及在由较差的土壤，较陡的坡度或南部和西部暴露的地区组成的更恶劣的生态场所中，具有较高的天然草叶发生频率。肯塔基草，光滑的溴，低灌木丛对我们所考虑的解释变量的反应各不相同，据报道，它们对火灾和放牧等管理行为的反应也各不相同。因此，如果其中有两个或多个入侵者发生，大草原管理者可能会在恢复管理中遇到重大挑战。通过了解与深层，边缘和景观特征有关的入侵方式，草原恢复主义者可以将注意力集中在恢复成功可能性更大的领域上，并更好地了解这些特征如何影响恢复成功或失败。