Grasslands provide a variety of vital ecosystem services, yet many are highly disturbed or degraded and require management to maintain and enhance biodiversity. Recent studies suggest that the soil microbial community may play a key role in the establishment of desirable species that provide key functions in managed grasslands, with the hypothesis that perennial, late-successional species are more dependent on mutualistic microbes found in high-quality remnant grasslands than early-successional or invasive species. Here we explore how different groups of grassland legumes (late-successional, early-successional, and invasive), which associate with both arbuscular mycorrhizal fungi and nitrogen-fixing rhizobia bacteria, respond to soil microbial communities from grasslands varying in land-use history. In a greenhouse study, we assessed growth and root-nodule production of plants inoculated with field soil collected from remnant prairies, post-agricultural grasslands, and agricultural sites.
Results/Conclusions
Contrary to expectations, we did not find strong differences between species types in response to microbial communities from different land-use histories. All species produced significantly more biomass when inoculated with field soil than when grown in sterilized controls, regardless of field soil origin, and tended to perform better with post-agricultural and remnant microbial communities than agricultural ones. Early-successional and invasive species (Chamaecrista fasciculata and Lespedeza cuneata, respectively) tended to produce the most biomass and were more likely to produce root nodules when grown with post-agricultural microbial communities. In contrast, the late-successional native species (Amorpha canescens) produced similar amounts of biomass and was equally likely to produce root nodules when grown with post-agricultural and remnant prairie microbial communities. These results suggest that legume species may differ in their responses to microbial communities from grasslands differing in land-use history; future work with additional legume species will further explore microbial community effects on plant growth, particularly the role of rhizobia.