Molecular evidence for impoverished mycorrhizal communities of Agropyron cristatum compared with nine other plant species in the Northern Great Plains

Authors: Reinhart, Kurt; Rinella, Matthew - Matt

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2020
Publication Date: 9/1/2020
Citation: Reinhart, K.O., Rinella, M.J. 2020. Molecular evidence for impoverished mycorrhizal communities of Agropyron cristatum compared with nine other plant species in the Northern Great Plains. Rangeland Ecology and Management. 74:147-150. https://doi.org/10.1016/j.rama.2020.08.005.
DOI: https://doi.org/10.1016/j.rama.2020.08.005

Interpretive Summary: • Problem- Large areas have been reseeded with crested wheatgrass. Managers are now often interested in diversifying these areas to make them more favorable to wildlife. However, the persistence of exotic species like crested wheatgrass has likely altered the soil biology of the site and may complicate attempts to restore it. • Accomplishment- This study determined that mycorrhizal fungi communities of dominant mixed-grass prairie plant species are dramatically different and more diverse than crested wheatgrass samples. • Theoretical implications- These findings when coupled with related studies suggest crested wheatgrass is having a soil legacy effect that likely complicates restoration efforts. • Management implications- Our findings suggest seeding areas with persistent cover of crested wheatgrass with plant species that are not dependent on mycorrhizal fungi. In addition, we also suggest that current practices of seeding with crested wheatgrass at energy sites requiring intermediate stages of restoration is likely to complicate final restoration efforts. We instead recommend seeding with species that host a diversity of mycorrhizal fungi.

Technical Abstract: Invasive plant species are capable of changing the community composition of arbuscular mycorrhizal fungi (AMF). Changes to AMF communities may contribute to the net negative impact of invasives on resident plants. Here we compared the AMF communities of the invasive grass Agropyron cristatum across six randomly selected sites where it has dominated for ca. 70 yrs to the AMF communities of eight common plant species from three sites of mixed-grass prairie vegetation in the Northern Great Plains. The richness of AMF communities associated with six of eight dominant plant species were greater than the AMF communities associated with A. cristatum. The percentage of roots colonized by AMF was also greater for seven of eight resident mixed-grass prairie species than A. cristatum. These findings support the observation that cultivars of A. cristatum are not mycorrhizal dependent and results of soil feedback experiments showing the capacity of this invasive plant to reduce AMF richness. These findings support our interpretation that persistent stands of A. cristatum are likely generating soil legacy effects that contribute to the persistence of A. cristatum and that limit species turnover back to mixed-grass prairie vegetation. These findings have important implications for the Applied Ecology of numerous areas already dominated by A. cristatum and refining restoration strategies for ongoing energy development across the Northern Great Plains.