The Wood Wide Web

Now that monsoon season is in full swing - one of my favorite times of the year, nothing is more exciting than seeing the thunderheads grow above the Sky Islands as we cross our fingers, hoping rain will come our way. And nothing is better than the petrichor that follows, a sweet mix of earth and creosote. The high desert surrounding Tucson is bright green and spiny; the grasslands are alive and dancing again, and the trees are full of movement. But something much smaller is also making moves after a long, hot summer. As monsoon rains create and maintain a moist environment within the surface of the soil, fungi begin to flourish throughout the coming fall. 

Southern jack-o-lantern mushroom (Omphalotus subilludens)

Often overlooked, mushrooms and their intricate mycelium networks are vital components of our ecosystems. While our arid climate might not seem conducive to fungal life, Arizona boasts a surprising diversity of fungi, many of which play crucial roles in maintaining ecosystem health. From the pine forests to the desert floors, fungi have adapted to thrive in diverse habitats across the state and the entire world.  

Beneath the surface of the soil, a hidden world of interconnected threads known as mycelium forms intricate networks. These networks are created by the branching filaments of fungi and serve as nature's communication and nutrient distribution systems. Mycelium networks play a crucial role in the health and functioning of ecosystems by facilitating nutrient exchange between plants, aiding in decomposition, and even providing defense mechanisms against pathogens. The mushrooms we see above ground are the fruiting body of the organism, and the majority of the fungal biomass is contained in the mycelium, which can be microscopically thin and hundreds of miles long. 

Mushroom species unknown

Ecosystem health is intricately linked to the vitality of mycelium networks. In forests, mycorrhizal fungi form symbiotic relationships with trees, aiding in nutrient uptake and promoting overall tree health. In arid regions, fungal decomposition of organic matter contributes to soil fertility and water retention, crucial factors for desert plant survival. Mycelium networks also act as biofilters, detoxifying soil and water by breaking down pollutants and contaminants.

Splitgill mushroom (Schizophyllum commune)

While mycology has been studied for centuries, the importance of mycelium networks in ecosystem health is a relatively new area of focus. As scientists dive deeper into the intricate interactions between fungi, plants, and soil, they uncover the indispensable role that fungi play in maintaining ecological balance. Research initiatives and collaborations are underway to better understand the dynamics of mycelium networks and their implications for conservation and restoration efforts. Entangled Life, by Merlin Sheldrake, is a wonderfully interesting and educational book that taught me a lot about what’s happening underground and made me think about all the invisible strings that connect us.

Mushroom species unknown

Since we’re on the subject of fungi, it is hard not to talk about lichens, which are a composite organism made up of an alga and a fungal species. These two organisms live together, providing each other with the nutrients and minerals the other cannot extract from their surroundings. Like much of mycology, lichens remain mysterious and puzzling - they don’t fit easily into any of the boxes we humans love to make. They leave us with many questions, like where does a mushroom fall on the spectrum between plant and animal? Should a lichen be considered one organism if it cannot live as separate beings? No matter how we choose to classify them, their ecological roles are critical. The beginning and end of the nutrient cycle are often associated with these organisms. Lichens are able to break down rock and other materials, which contributes to sediment formation. Fungi are known as decomposers that return nutrients to the soil. 

Rock-shield lichens, genus Xanthoparmelia

As we continue to unravel the mysteries of fungal ecology, we gain a deeper appreciation for the interconnectedness of all living organisms and the delicate balance that sustains life on Earth. By protecting and celebrating these fungal marvels, we not only conserve the health of Arizona's ecosystems but also contribute to the broader understanding of biodiversity and ecology.