Ecological restoration has become an essential strategy for reversing biodiversity declines and increasing ecosystem services in degraded ecosystems. However, the outcomes of individual restoration efforts are highly variable, and understanding the causes of this variation is necessary as we work toward more reliable restoration outcomes. While variation in restored plant communities is relatively well studied, assembly of arbuscular mycorrhizal fungi (AMF) communities is likely an important component of restoration success and the recovery of soil ecosystem services, yet we know relatively little about the drivers of assembly of soil communities during ecological restoration. We characterized the diversity and composition of plant and AMF communities within 77 restored tallgrass prairies in Michigan, Indiana, and Illinois. Additionally, we collected data on potential drivers of community assembly, including site age, soil texture, fire history, and resource availability. We used linear models to identify the most important predictors of plant and AMF diversity, and we used PERMANOVA to identify the most important drivers of variation in community composition.
Results/Conclusions
We find that the diversity of plants and mycorrhizal fungi in restored communities is not well predicted by our explanatory variables (p > 0.3). In contrast, we are able to explain some variation in community composition, with similar variables explaining variation in plant and fungal community composition. Site age, soil texture, and fire history are all statistically significant explanations for variation in plant and fungal community composition, though each explains a relatively small proportion of variation (PERMANOVA r2 =0.02-0.04, p < 0.04). However, light availability (r2 = 0.06) and location (MI, IN, or IL, r2 = 0.11) are important explanations for variation in plant community composition but are not significant predictors of variation in AMF community composition. We also find that much of the variation in community composition remains unexplained (residual r2 = 0.69 and 0.85 for plants and AMF respectively). Overall, we find that plant and AMF communities in restored grasslands are responsive to similar environmental conditions, including site age, soil texture, and fire history.