EMCI is thrilled to learn that our grantee, Professor Pete Avis (UMaine), and his colleague, Evan Warburton, recently had their paper, “The ectomycorrhizal fungal communities of 9000-year-old red spruce forests on a coastal island of northeastern North America,” published in the journal Mycorrhiza. This paper documents the work our funding supported, and we send them our hearty congratulations!
Dr. Avis has prepared the following summary for us:
What are “Ectomycorrhizal Fungi”?
Trees don’t grow in a vacuum; they rely heavily on underground networks of fungi called ectomycorrhizal (ECM) fungi. These fungi attach to tree roots, effectively acting as an extended root system. In a mutual “trade,” the fungi absorb water and vital nutrients from the soil for the tree, and in return, the tree gives the fungi sugars it creates through photosynthesis.
What Did the Study Investigate?
While these underground networks are well-studied inland, researchers wanted to look at how they behave in ancient, isolated environments. They traveled to a coastal island in Maine, USA, to study four ancient red spruce forest sites (where spruce trees have continuously grown for about 9,000 years) and compared them to a nearby beech-birch forest site.
They took DNA samples from:
- The roots of young seedlings
- The roots of mature, grown trees
- The “bulk soil” surrounding them (where no roots were present)
Key Findings
- The Big Three: The ancient red spruce networks are heavily dominated by three specific types of fungi: Cenococcum, Piloderma, and Cortinarius.
- Family Resemblance: Within the spruce forests, the same dominant fungi were found across the board—whether they looked at baby seedlings, mature trees, or the bare soil. This means the helpful fungi are firmly established everywhere in the forest floor, waiting to support the next generation of trees.
- Tree Identity Matters: There was almost zero overlap between the fungi found in the red spruce forests and the fungi found in the beech-birch forest. This proves that the types of trees growing above ground strictly dictate what kind of fungal community lives below ground, much like how it works on the mainland.
Why Does This Matter?
Island ecosystems and old-growth forests are incredibly vulnerable to climate change and human disruption. By mapping out these 9,000-year-old underground partnerships, scientists can better understand how to protect these ancient coastal forests and help them regenerate.
AUTHOR BIOS:
Pete Avis lives in Orono and is Assistant Professor of Ecosystem Genetics with the School of Ecology and Biology at the University of Maine and formerly an associate professor of Biology at Indiana University Northwest. His PhD is from the University of Minnesota. He’s studied mycorrhizal fungi for over 30 years.
Evan Warburton graduated from the University of Maine a few years ago. He worked at the Pacific Northwest National Laboratory in Washington and now lives and works in Philadelphia. He remains enthusiastic about mycorrhizal fungi and how they interconnect forests belowground.
A few pictures and captions below: Top left – Evan and Pete catching the boat from Roque Bluffs; Top right – the reproductive part of one ectomycorrhizal fungus, a chantarelle. Lower left – mushrooms of another ectomycorrhizal fungus in the genus Cortinarius. Lower right – roots of a spruce seedling colonized by ectomycorrhizal fungi.
