Key soil biota may facilitate and/or inhibit plant invasions. To address this broad topic, I will briefly review a series of case studies. This series will address several topics including: i) biogeographic variation in the virulence of soil-borne pathogens in a tree’s native and non-native ranges; ii) whether mycorrhizal effects, and plant-soil feedbacks more generally, depend on a plant’s invasive status; and iii) effectiveness of putative weed-suppressive bacteria strains.
Results/Conclusions
As a group, invasive plants tend to respond similarly to soil biota (mycorrhizal responsiveness [p ≥ 0.16], plant-soil feedback [p = 0.13]). However, individual invasive plants have varying interactions with soil biota which are difficult to predict and may be of ecological importance. In support of the enemy release hypothesis, Pythium pathogens from a tree’s native range caused 38–462% more root rot (p = 0.011) and 80–583% more seedling mortality (p = 0.013) than Pythium from the non-native range. Depending on experiment type (petri-plate [p < 0.0001], plant-soil bioassay [p ≥ 0.13], and field experiment [p ≥ 0.2]), soil bacteria strains indicated some capacity to function as a bioherbicide and control an invasive annual grass. Overall, soil biota are one of many factors which impact the success and failure of invasive plants.