Agricultural cultivation in the Midwestern United States has caused an 82-99% decline in the tallgrass ecosystems that once dominated North America and has severely impacted the ecosystem services they provide. Current prairie restoration and land management approaches focus on improving aboveground ecosystems, but are poorly integrated with restoration of soil microbial biodiversity and carbon cycling. Restored prairies harbor microbial communities that metabolize more labile forms of carbon and have greater rates of soil respiration than pristine remnant prairies, suggesting that traditional prescribed burn approaches lead to an alternative stable belowground community. In this study, we examine whether inoculation with microbial communities obtained from a remnant prairie soil source promote resilience restored soil microbial communities to environmental variation. Specifically, we examined whether inoculation reduces the effects of warming on restored soils in a greenhouse experiment. We compared inoculation with live soil communities to inoculation with a high molecular weight carbon substrate (cellulose) as a selection mechanism for remnant-like microbial communities. Following inoculation, we examined16S rRNA-based soil microbial biodiversity, extracellular enzyme activities of B-glucosidase, cellobiohydrolase, N-acetylglucosaminidase and phosphatase and microbial utilization of 31 carbon substrates using a Biolog Ecoplate approach.
Results/Conclusions
Overall, our results demonstrate that warming increases the variability of soil microbial community composition, enzyme activity and carbon utilization, suggesting that restored prairie soil microbial activity will be strongly affected by a 4-degree increase in temperature. However, pots that were inoculated with cells prepared from the remnant soil extract exhibited less variability under the warming treatments than the controls. This suggests that inoculation with remnant prairie soil microbial communities can be used as a tool to stabilize newly restored prairie soils. We developed and tested this technique for use in a field-level application and the approach is straightforward and not economically prohibitive to conduct for land managers who wish to improve belowground restoration on their properties.