Fungi are a persistent legacy : drivers of fungal abundance and community composition over time

Abstract

Plants are a major force shaping how ecosystems function, including non-native plants. The effects that non-native plants have on ecosystem properties and processes can be particularly important as invasive plants are associated with changes in nitrogen and carbon cycling Plants can also indirectly affect ecosystem processes through their influence on the soil microbial community and different plants are associated with different microbial communities. The legacies produced by invasive plants can be long-lasting and inhibit the restoration of damaged ecosystems. Because of the central role of soil fungi in ecosystem processes, I examined how fungal abundance and community composition were altered by non-native plants, and the persistence of these changes. Specifically, I examined how two different cases of invasion by non-native species affected soil fungi over three years compared to soil fungi in native, undisturbed sites. I further tested how the soil fungi responded to the removal of the non-native plants and to inoculation with local native microbial communities. Legacy effects of land use history on soil fungal abundance and community composition were found in these central Florida communities. There were substantial differences in soil fungal abundance and community composition in disturbed and pasture sites compared to native scrub, and these differences persisted for three years after non-native grasses were removed. Not only did the grass-dominated pasture and disturbed sites differ from the undisturbed native shrub-dominated ecosystem, they differed significantly from each other, indicating that the different non-native grasses and other specific changes associated with each land use played a role in soil fungal communities. The combined results of this study have implications for restoration ecology. The current dependence of the fungal community on land use and the associated non-native species invasions (along with other analyses done in this system) suggest that a different approach to restoration is required here to overcome the observed legacy effects.