As invasive plants establish in local ecosystems, they encounter a wide range of trophic interactions with resident species. Most documented interactions are direct, but invasive plants can also influence native community members indirectly by altering the abundances of intermediate-level species in terrestrial food webs (Weidenhamer & Callaway 2010; Lau 2013). These trophic interactions underpin some of the most important changes that biological invasions can inflict on ecosystem structure, leading to species extinction and major shifts in community composition (Vitousek et al. 1997; Vilá et al. 2011). For example, many invasive plants alter microbial activity, disrupting key mutualistic interactions and resulting in the displacement of native
