Impacts of prairie grass species restoration on plant community invasibility and soil processes in abandoned agricultural fields

Question: Can plant species with particular traits be used to address common problems encountered during agricultural land restoration, including invasion by undesirable species and altered soil conditions? How does the establishment of dominant old-field and prairie grasses with different functional traits affect community invasibility and soil nitrogen (N) cycling in abandoned agricultural fields? Location: W.K. Kellogg Biological Station, Hickory Corners, Michigan, USA. Methods: We established seedlings of several common old-field and prairie grasses in a Trait Assessment Study to determine the magnitude of species differences in traits expected to influence community invasibility and soil processes. We also established monocultures of these species in a field experiment to determine how species with particular traits impacted community invasibility and soil processes 2 and 4yr after restoration. Results: The prairie species consistently produced more shoot, root and litter biomass, and had more recalcitrant tissue than the old-field species, and there were corresponding differences in invasibility and nutrient cycling. Soils under the three prairie grasses had significantly lower inorganic N after 2yr and significantly lower potential N-mineralization after 4yr. The prairie plots also had significantly less invasion than the old-field plots after 4yr. Plots dominated by the old-field species had higher biomass of non-native species, and higher numbers of colonizing species than plots dominated by prairie species. Conclusions: Restoration using prairie grasses with particular effect traits can reduce N cycling and availability, and lead to a decrease in invasion by undesirable species from adjacent unrestored sites.