Non-native plants degrade native plant communities, lowering the value of affected ecosystems to humans. Understanding the mechanisms that promote invasion by non-native plants into native communities, while necessary for the development of effective control strategies, represents a major challenge for ecologists. Central to plant competitive relationships are arbuscular mycorrhizal fungi (AMF). These plant symbionts depend completely on the plants that host them for energy. In return, the fungi form hyphae that greatly extend the plants effective root system, increasing uptake of important nutrients, while offering a degree of protection against pathogens. Previous work has shown that plants can influence the composition of AMF infecting its neighbors. Since different AMF species differ in the services they supply to different plants, this could represent a key mechanism determining the outcome of plant competitive relationships. The goal of this research is to elucidate these relationships. A series of experiments will be conducted to determine: (1) the extent to which neighboring plant species identity differentially influences AMF community compositions in roots; (2) the role of host identity in determining the functional attributes of specific AMF species; (3) whether the presence of a given AMF species alters the functional attributes of co-infecting AMF species; and (4) whether alteration of AMF community compositional and functional attributes due to neighbor effects differentially drive coexistence or facilitate invasiveness when neighboring plants are either native or non-native species.

In addition to leading potentially to improved strategies for the control of alien plant species, broader impacts of this work include providing opportunities for members of the local community to become involved in hands-on ecological research through workshops covered by the media (TV and newspaper). Additionally, the work will provide opportunities for students, including underrepresented groups via the NSF-funded project TRAIN, in the science of microbial and ecosystem ecology.

National Science Foundation (NSF)
Division of Environmental Biology (DEB)
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Alan James Tessier
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University of Montana
United States
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