Nov. 19—ANDERSON — With each step hikers take along the trails of Indiana's state forests, they're coming closer than they realize to a vast microbial network that some scientists believe could play a vital role in mitigating climate change.
"As you're walking, there's about 300 miles of fungi under every footstep that you take, and that's all over the world," Suzanne Simard, a professor of forest ecology at the University of British Columbia, says in "Fantastic Fungi," a 2019 documentary examining how fungi contribute to the sustaining and regeneration of plants and microorganisms in nature.
Fungi are seen by many researchers as the threads that help stitch ecosystems together. They attach themselves to plant roots and diverge in all directions, indirectly connecting the most majestic trees with the tiniest sources of nitrogen and other elements needed to maintain life. Mycelia, the root-like structures of fungi, are the vessels through which this connection happens.
"Almost everyone knows about the computer internet. The mycelium shares the same network design," mycologist Paul Stamets says in "Fantastic Fungi."
In Indiana, fungi are also seen as indispensable in keeping harmful pests at bay and preserving the overall health of vegetation in the state's 4.2 million acres of forest lands. Of particular concern is the Asian jumping worm, which looks very similar to the European earthworm, but instead of contributing nutrients to the soil through their excrement, they consume expansive amounts of organic matter, robbing nearby plants of a vital source of nourishment.
"They end up turning the organic matter and topsoil at the edge of a forest into almost a coffee ground-type consistency, which makes it very difficult for our traditional native Indiana plants to grow," said Hans Schmitz, a conservation agronomist with the Purdue Extension's Conservation Cropping Systems Initiative.
Scientists have also noted that gradually rising temperatures in many parts of the world — including the Midwest — may begin to affect fungi's ability to replenish nitrogen and other elements in the soil.
"Fungi and microbial activity in soil is highly affected by soil temperature, so canopy closure is extremely important for regulating soil temperature," Schmitz said.
"A soil that is shaded all of the time is going to be substantially cooler than one that is receiving direct sunlight, so as we look at land use, land cover and climate change in soils, being sure that we have something growing at all times on top of our soils and being able to regulate that temperature is very important."
Those findings, Schmitz noted, carry ramifications for farmers and conservationists alike as crop rotations and other land management methods continue to undergo scrutiny.
"That's why we kind of see a little bit more focus on conservation cropping and the wetland restoration and returning some of our acres to more native habitats," he said.
"Many laboratories are now actually ... trying to identify specific fungi populations and the amount of that population that is available in the soil with the knowledge that there are beneficial fungi, and the higher your fungal population in the soil, it's one indicator of productivity of that soil."
Another area of concern is fungi's role in helping trees, plants and other vegetation recover from catastrophic weather events. Although research on this topic has been sparse, according to Schmitz, a general principle holds that recovery happens more quickly in forested areas due to higher volumes of organic matter in the soil there. The more organic matter present, Schmitz said, the more fungi can help nature heal itself.
"Generally speaking, because that forested ecosystem with the high amount of leaf litter and organic matter that settles in that situation, we should expect to see fungi be a very large part of the recovery of that system due to the high initial populations," he said.
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