Do plant–soil interactions influence how the microbial community responds to environmental change?

Brigham, L.M., Bueno de Mesquita, C.P., Smith, J.G., Sartwell, S.A., Schmidt, S.K., and Suding, K.N. In Press. Do plant–soil interactions influence how the microbial community responds to environmental change? Ecology, e03554. Available at https://doi.org/10.1002/ecy.3554

Moist meadow at Niwot Ridge is co-dominated by Geum rossii, the prolific yellow flower in this photo. Geum was one of two plant species removed as part of the co-dominant removal portion of this long-term experiment. Photo credit: J. Smith

Abstract

Global change alters ecosystems and their functioning, and biotic interactions can either buffer or amplify such changes. We utilized a long-term nitrogen (N) addition and species removal experiment in the Front Range of Colorado, USA to determine whether a co-dominant forb and a co-dominant grass, with different effects on nutrient cycling and plant community structure, would buffer or amplify the effects of simulated N deposition on soil bacterial and fungal communities. While the plant communities were strongly shaped by both the presence of dominant species and N addition, we did not find a mediating effect of the plant community on soil microbial response to N. In contrast to our hypothesis, we found a decoupling of the plant and microbial communities such that the soil microbial community shifted under N independently of directional shifts in the plant community. These findings suggest there are not strong cascading effects of N deposition across the plant–soil interface in our system.