Abstract
Interactions between soil nitrogen (N) availability, fungal community composition, and soil organic matter (SOM) regulate soil carbon (C) dynamics in many forest ecosystems, but context dependency in these relationships has precluded general predictive theory. We found that ectomycorrhizal (ECM) fungi with peroxidases decreased with increasing inorganic N availability across a natural inorganic N gradient in northern temperate forests, whereas ligninolytic fungal saprotrophs exhibited no response. Lignin-derived SOM and soil C were negatively correlated with ECM fungi with peroxidases and were positively correlated with inorganic N availability, suggesting decay of lignin-derived SOM by these ECM fungi reduced soil C storage. The correlations we observed link SOM decay in temperate forests to tradeoffs in tree N nutrition and ECM composition, and we propose SOM varies along a single continuum across temperate and boreal ecosystems depending upon how tree allocation to functionally distinct ECM taxa and environmental stress covary with soil N availability.
| Original language | English |
|---|---|
| Pages (from-to) | 391-404 |
| Number of pages | 14 |
| Journal | Ecology Letters |
| Volume | 25 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2022 |
| Externally published | Yes |
Funding
We thank Nisha Gudal, Liberty Woodside, Melissa Chen, Noor Ahmad, and Catherine Seguin for assistance with fine root processing. We also thank Diana Saum, Kirk Acharya, Samuel Schaffer‐Morrison, Jordan Matthews, Edith Juno, and Gwendolen Keller for field assistance. We are very grateful to Stuart Grandy for py‐GC/MS analysis of soil samples. We thank Deborah Goldberg and Inés Ibáñez for insightful comments on earlier versions of this manuscript. We also thank Timothy James for valuable comments on previous drafts of this manuscript and assistance with ITS2 barcoded primer protocols. We are grateful to Christopher Blair, Christina Cartaciano, and Thomas Schmidt at the University of Michigan Microbiome Core for ITS2 sequencing. We also thank Beth VanDusen and Jennifer Wen for additional assistance with characterisation of soil chemistry, as well as Ojen's Alterations for litter bag construction. We are very grateful to three anonymous reviewers for their insightful and constructive comments during the review process, which have helped us substantially improve our manuscript. This work was supported by funding from the National Science Foundation, the School for Environment and Sustainability, and the Rackham Graduate School at the University of Michigan.