Mycorrhizae and the Web of Life

Red squirrel savoring a snack © 2012 Beatriz Moisset

By now we have become familiar with the concept of a garden as an ecosystem or as a community with all sorts of associates, including plants, birds, insects and others. All of them complement each other and compete with each other. If you pull one thread of this tapestry, you can feel the repercussions in near and distant parts. But many times we don’t think about the partners underground. Their interconnections are just as complex, or even more so. I talked about the fungi called mycorrhizae in my recent post “Root Partners, Mycorrhiza” and want to take the subject a little further.

There are thousands of species of mycorrhizal fungi. They often intertwine with each other and with the roots of numerous plant partners of the same or different species. They also associate with soil bacteria, including valuable nitrogen-fixing bacteria. So they form an intricate network which can cover vast expanses of land. Some workers feel that the whole forest is one enormous partnership, which they call the “Wood Wide Web“. Such inter-connectivity confers tremendous resilience to a system.

A beautiful explanation of this web of life is the illustration “A Thousand Words” of the Australian Fungi Website. Although to me it is worth far more than a thousand words.

© Heino.ANBG fungal site

Let us skip #1 for now:
2 (green) and 3 (violet): Two mycorrhizal fungi, one produces above-ground mushrooms and the other below-ground truffles as fruiting bodies. The mycelium of #2 reaches three different trees, while that of #3 connects with just two trees. Both mycelia are surrounded by symbiotic bacteria.
4: A small tree, growing shaded under the canopy of larger ones. It may be getting some nourishment indirectly from them by means of the interconnecting mycelia.
5 (orange): Another type of mycorrhiza. It forms a different kind of fruiting bodies called corticioid; flat structures seen on decaying wood or on mosses. We see them as disease or decay, but more often than not corticioid fungi are mycorrhizal and thus significant parts of the plant community. This is another example of a largely ignored member of ecosystems. Who would think of their beneficial function with such plain appearance?
1: Finally, what would a society be without a few freeloaders? Two kinds are illustrated here.
1 (red): A parasitic mushroom, drawing food from a tree and returning nothing.
1 (black): Another kind of parasite; this time a flowering plant, such as Indian pipe. These plants have lost all chlorophyll and are dependent on fungi, not only parasitic ones as the one illustrated here but also mycorrhizal. So, indirectly they parasitize the trees.

Tomentella radiosa, a corticioid fungus. © Gerhard Koller. Wikicommons

Indian pipe, a parasitic flowering plant © 2012 Beatriz Moisset

You may be wondering what the bushy tailed little rascal perched on a pine tree is doing in an article on mycorrhizae. Squirrels, as well as other animals, are an integral part of a community. Many fungi need helpers to spread their spores. This is similar to the association between flowering plants and pollinators. The fleshy mushrooms provide food for small creatures such as squirrels, chipmunks and beetles. Truffles, being underground, resort to strong aromas to attract hungry seekers. In some cases, these odors resemble sexual pheromones, driving some male animals to distraction. Flying squirrels are very effective at finding truffles. Spores have a tough, acid-proof coating so they can survive the trip through the intestines if they get eaten and end up being deposited some distance from the parent organism.

A community made entirely of native organisms has evolved an optimal balance of the parts above and below ground. Disturbed soils have lost more than the flora above ground; they have also lost much of their native mycorrhizae and soil bacteria. Many invasive plants do well without these soil components (probably that is why they are so invasive). Non-natives, such as garlic mustard and thistle illustrate this situation. They prosper and prevent the growth of mycorrhizae and, by extension, the restoration of native plants. This is another tragic example of the ecological disruption caused by non-natives. In some cases it may be necessary to inoculate mycorrhizae when trying to restore disturbed soils.

I never cease to marvel at the constellation of relationships in a garden. It includes native plants, the insects that feed on them, the wildlife that feed on such insects, the pollinators, the birds that spread seeds, and, last but not least, the mycorrhizae, other soil organisms, and the animals that take care of the mycorrhizae reproduction.

Mycorrhizal mushroom. © 2012 Beatriz Moisset

More on mycorrhizae:
Mycorrhiza Primer
The Use of Mycorrhizal Fungi in Erosion Control Applications

© 2012, Beatriz Moisset. All rights reserved. This article is the property of Native Plants and Wildlife Gardens. If you are reading this at another site, please report that to us

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About Beatriz Moisset

Born in Argentina and a resident of the United States for about forty years. A biologist by profession and a photographer and painter by avocation. I finally found the way to combine all these different interests in one single package when I became interested in pollinators. I have been photographing and painting them and studying their biology and ecology and I probably could spend the rest of my life doing so because the subject is endlessly fascinating and of tremendous esthetic, ecological and economic importance. Author, with Steven Buchman, of Bee Basics: An Introduction to Native Bees


  1. Donna@ Gardens Eye View says:

    Beatriz I am so glad to see the continuation of this subject. As a humble gardener my self education lacks some of this fascinating science and how it all connects. I often wondered who was eating the fungi in my yard and on my decaying stump. I love learning the intricacies of life below ground…thx for this education and I hope the subject continues…
    Donna@ Gardens Eye View recently posted..Gardens Eye Verse-March

  2. Phil (Smiling Gardener) says:

    Thanks, great article! Interesting info on the different types of mycorrhizal fungi.

    Of all the amazing things these fungi do for plants, one that always blows me away is that many of the plants in an ecosystem are connected together by these fungi and will actually share nutrients with each other via the mycorrhizal network. The fungi are truly integral to the health of a forest and a garden. Thanks again.
    Phil (Smiling Gardener) recently posted..Plant Diseases And Pests Aren’t Caused By A Lack Of Pesticides

  3. Forest Keeper says:

    As an arborist I have been fascinated by the subject of mycorrhizal fungi for quite some time. I love learning about the micro biology of soil. Paul Stamets has written many fascinating books on this subject and has done some remarkable research in this field.
    Thank you for the great post!
    Forest Keeper recently posted..Planting Healthy Trees- You Can Grow That-March edition

    • Gloria says:

      Thanks for the link to Paul Stamets. The Ted talk video and the articles online are very interesting.
      Gloria recently posted..Winter in a our back garden

  4. Gloria says:

    A wonderfully helpful illustration showing the connections including ,I noticed, the decaying organic matter laying on the soil.
    Gloria recently posted..Winter in a our back garden

  5. UrsulaV says:

    Flying squirrels and truffles! My mind is blown.

  6. Loret says:

    Love fungi, fascinating subject
    Loret recently posted..Responsibility on the Internet

  7. Matt says:

    So what is the best way to foster mycorrhizal fungi in my suburban yard? . . . . compost? add it?

    • Beatriz Moisset says:

      This is a very important question; but one I don’t dare to tackle. Perhaps, some of the people with more practical knowledge than me will have some suggestions.
      Beatriz Moisset recently posted..Noctuids, another family of little known pollinators

  8. Diane St John says:

    I love this topic! When I started gardening I really had no idea about this and would rake my leaves away. I think the best way to get the life going in the soil is to nourish with leaves, the way nature has done forever. It is so interesting how it is all connected!
    Diane St John recently posted..No One Ever Fertilized An Old Growth Forest

  9. Debbie Roberts says:

    Great post, I especially love that illustration…it makes it all fall into plae so easily.
    Debbie Roberts recently posted..Wordless Wednesday ~ Yellow

  10. The Local Scoop says:

    The pic of the squirrel is a red squirrel (Tamiasciurus hudsonicus). It is a resident of coniferous forests (versus the gray squirrels of deciduous forests).

    • Beatriz Moisset says:

      Thanks for catching that. Now I remember that I substituted one image for another and forgot to change the caption. I will do it right now. Thanks.

  11. Todd@BigBlogOfGardening says:

    Excellent article. These fungi are so important, it can’t be understated. The interdependent relationship between plants and everything that lives on the earth is fascinating.
    Todd@BigBlogOfGardening recently posted..Spring lawn care – an organic guide



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