Hannah B. Shulman

Question: In alpine meadow ecosystems of the Rocky Mountains, we studied how arbuscular mycorrhizal fungi (AMF) and soil bacteria drive ecosystem responses to warming. Our goal is to understand how both long term warming and acute warming (e.g. earlier snowmelt timing in spring) impact AMF, their bacterial partners, and the plants they support.

Team: I worked on this project with Dr. Stephanie Kivlin, Dr. Aimée Classen, Dr. David Inouye, Ian Breckheimer, as part of a long-term collaboration based at the Rocky Mountain Biological Laboratory. This work was supported by a grant from the DOE Earth System Science program.

Findings: Warming disrupts the coordination between plants, mycorrhizal fungi, and their bacterial partners at the community scale. Early snowmelt decouples plant and arbuscular mycorrhizal fungal (AMF) phenology, disrupting phosphorus (P) cycling. Long-term warming also decouples AMF and P-cycling bacterial communities belowground. Both of these responses to warming mirror how AMF and P-cycling bacteria naturally assemble across climate gradients with elevation, showing that warming may be pushing ecosystems toward the assembly patterns and P-cycling processes typically seen at lower, warmer sites.

Our current and future work will investigate whether this community decoupling is a driver of regime shifts (such as woody plant encroachment) in montane ecosystems.