Climate change–induced stress disrupts ectomycorrhizal interaction networks at the boreal–temperate ecotone

Journal Article · Mon Aug 14 00:00:00 EDT 2023 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.2221619120· OSTI ID:1995031

Fernandez, Christopher W. ^[1]; Mielke, Louis ^[2]; Stefanski, Artur ^[3]; Bermudez, Raimundo ^[3]; Hobbie, Sarah E. ^[4]; Montgomery, Rebecca A. ^[5]; Reich, Peter B. ^[6]; Kennedy, Peter G. ^[7]

---

1. Department of Biology, Syracuse University, Syracuse, NY 13210, Department of Plant &, Microbial Biology, University of Minnesota, Saint Paul, MN 55108
2. Department of Plant &, Microbial Biology, University of Minnesota, Saint Paul, MN 55108, Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala 750 07, Sweden
3. Department of Forest Resources, University of Minnesota, Saint Paul, MN 55108
4. Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108
5. Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia
6. Department of Forest Resources, University of Minnesota, Saint Paul, MN 55108, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2751, Australia, Institute for Global Change Biology, and School for Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109
7. Department of Plant &, Microbial Biology, University of Minnesota, Saint Paul, MN 55108, Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, MN 55108

The interaction networks formed by ectomycorrhizal fungi (EMF) and their tree hosts, which are important to both forest recruitment and ecosystem carbon and nutrient retention, may be particularly susceptible to climate change at the boreal–temperate forest ecotone where environmental conditions are changing rapidly. Here, we quantified the compositional and functional trait responses of EMF communities and their interaction networks with two boreal ( Pinus banksiana and Betula papyrifera ) and two temperate ( Pinus strobus and Quercus macrocarpa ) hosts to a factorial combination of experimentally elevated temperatures and reduced rainfall in a long-term open-air field experiment. The study was conducted at the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment in Minnesota, USA, where infrared lamps and buried heating cables elevate temperatures (ambient, +3.1 °C) and rain-out shelters reduce growing season precipitation (ambient, ~30% reduction). EMF communities were characterized and interaction networks inferred from metabarcoding of fungal-colonized root tips. Warming and rainfall reduction significantly altered EMF community composition, leading to an increase in the relative abundance of EMF with contact-short distance exploration types. These compositional changes, which likely limited the capacity for mycelial connections between trees, corresponded with shifts from highly redundant EMF interaction networks under ambient conditions to less redundant (more specialized) networks. Further, the observed changes in EMF communities and interaction networks were correlated with changes in soil moisture and host photosynthesis. Collectively, these results indicate that the projected changes in climate will likely lead to significant shifts in the traits, structure, and integrity of EMF communities as well as their interaction networks in forest ecosystems at the boreal–temperate ecotone.

• Sponsoring Organization: USDOE
• OSTI ID: 1995031
• Alternate ID(s): OSTI ID: 2417741
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 34 Vol. 120; ISSN 0027-8424
• Publisher: Proceedings of the National Academy of Sciences
• Country of Publication: United States
• Language: English