The Hidden Fungi of Great Basin National Park

Adapted from an article by interpretive park ranger Lisa Johnston in The Midden*, Great Basin National Park's newsletter, Winter 2018.*

The aspen bolete, Leccinum insigne*, a mycorrhizal fungus that grows near quaking aspen. Image from the National Park Service's page.*

On your next hike, look closely at the trees. From almost anywhere you stand, you can see every stage of growth and decay. You may not see a single mushroom unless it has rained recently, but the fungi that produce them are all around you, and without them the forest would look very different.

Recyclers of the forest

Fungi are major suppliers of nutrients in the forest. Most obviously, they break down lignin and cellulose, the tough materials of wood, so that trees can return to the soil they grew from. Few other organisms can digest them.

Fungi that decay wood are saprotrophic: they feed by breaking down dead material. In Great Basin National Park they include the oyster mushroom, Pleurotus populinus, which grows on fallen and standing dead quaking aspen, and the purple-tinged Trichaptum abietinum, found on rotting conifers.

The oyster mushroom, Pleurotus populinus*, a wood-decay fungus found on quaking aspen logs and snags. Image from the National Park Service's page.*

Partners of trees

Other fungi help keep trees and plants healthy by trading nutrients with their roots, a partnership called mycorrhiza. All mushroom-producing fungi grow as long threads called hyphae that run through the material they live in. Mycorrhizal fungi wrap their hyphae around the cells of plant roots or grow right into them. This greatly increases the surface area through which water enters the combined root-and-fungus system, and delivers nutrients the plant could not otherwise reach. In return, the fungus gets carbohydrates the plant makes by photosynthesis. Sometimes the exchange tilts toward one side and becomes parasitic, but usually both benefit. The aspen bolete, Leccinum insigne, is one such partner of quaking aspen in the park.

A kingdom of their own

Fungi are neither plants nor animals but a separate kingdom of life, and their ways of living are just as varied. Some are predators that use chemical lures to attract and trap tiny animals such as nematodes or springtails; others are parasites of insects or plants.

Rarely noticed, fungi are an essential part of Great Basin's ecosystem. Each short-lived mushroom is a sign of a large living organism that has been growing underground, waiting for rain.

Sources

• National Park Service, Great Basin National Park, "Introduction to Fungi in Great Basin National Park," by Lisa Johnston, originally in The Midden, Vol. 18, No. 2 (Winter 2018). https://www.nps.gov/articles/000/introduction-to-fungi-in-great-basin-national-park.htm