Fungi: an immense kingdom to discover and protect

They are neither plants nor animals, although they play equally decisive roles in the balance of ecosystems. We are talking about the fungi kingdom, of which mushrooms are the best known representatives, but there is a lot more to discover.

It is estimated that there are between 2.2 and 3.8 million species, but only around six hundred of them are rated on the IUCN – International Union for Conservation of Nature – Red List of Threatened Species, which says a lot about how little we know about the biodiversity and conservation of the immense kingdom of fungi.

Mushrooms are the best known celebrities of the kingdom, because their above-ground appearance makes them easier to identify, but there are many other hardworking fungi that operate ‘hidden’ from view and help to balance the Earth’s various biomes. Although little known and undervalued, they play a decisive role in numerous structural functions for life, from the cycling of nutrients to the production of medicines and food:

• Some 80% of land plants, including large trees in our forests and food crops, depend on their interactions with fungi (mycorrhizae). In addition, the decomposition of organic matter would not take place at all without their help (and that of other organisms, such as bacteria). As a result, all “organic waste” would accumulate on the ground. The nutrients essential for plant growth would not be renewed and the soil itself would not renew itself or be able to store carbon as it does today.
• The mould which gave rise to penicillin, known to be the first antibiotic ever isolated, also belongs to this kingdom — it is the microfungus of the genus Penicillium. Less well known but equally important, the fungus Tolypocladium inflatum is used as an immunosuppressive drug during organ transplantation and in the treatment of autoimmune diseases.
• Similarly, yeasts (Saccharomyces), which are involved in fermentation and the growth of cereals that are used to make bread and beer, or in the production of wine from grapes, also belong to the fungi kingdom, and are single-celled fungi.

These are just a few examples of fungi and the benefits they provide us with. The benefits they provide make up for their bad reputation, since the concept of fungus is still closely associated with the diseases they cause, both in animals and plants. So long as this negative perception persists, it will be more difficult to muster the commitment and resources needed to understand and catalogue fungal biodiversity, permitting us to anticipate the negative impacts that extinctions in this kingdom can have and even to predict and prevent the evolution of fungal diseases.

Did you know that…

• Some soil fungi establish a mutually advantageous relationship (symbiosis) with plant roots. In this association, called mycorrhiza, fungi receive the sugars produced in photosynthesis from plants and plants benefit directly from the transport of mineral nutrients and water carried by the fungus. Just as their lives are interconnected, so are many of the risks associated with diminishing diversity.
• There are different types of mycorrhizae. Those in which fungi form on the roots of plants, called ectomycorrhizae, are the most common in temperate climates, the most representative worldwide, and promote the greatest retention of carbon in the soil. With rising temperatures and changes in rainfall patterns caused by climate change, ectomycorrhizae and the important role of soil as a carbon sink could be at risk.
• The thing we call a mushroom is the visible part (fructification) of a group of multicellular fungi. Many of these fungi are edible and at least 350 different edible species have been identified worldwide. Among the best known and most appreciated edible varieties in Portugal are Boletus edulis, known as cep or porcini mushrooms, and Cantharellus cibarius, known as the golden chanterelle mushroom. The former is an autumn species, classified as “Least Concern” by the IUCN, and the latter, which grows in spring and autumn, has not been rated.
• Fungi can also establish mutualistic relationships with algae (and cyanobacteria). In this case, they generate new living beings: lichens or lichenised fungi, another group about which there is also still plenty to discover. It is estimated that between 17 and 30% of fungi are capable of converting into lichens, but it is not known how many species of lichen there are. There are estimated to be at least 18,000, but this number is likely to be much higher. They are able to grow on a wide variety of surfaces, including on soil, rocks, walls, and tree trunks.

More information on fungi to help prevent risks and losses

Of the 2.2 to 3.8 million species of fungi thought to exist globally, only 148,000 have been identified. In a single year (2019), 1886 “new” species were scientifically named, points out the State of the World’s Plants and Fungi 2020, which warns that “often, by the time a new species is named and described, it already faces a risk of extinction”.

This risk was underlined by a wide range of scientists who, in 2021, signed a petition to include the fungi kingdom in the global targets for biodiversity protection (in definition, at the United Nations Conference on Biodiversity – COP15). The experts recommended that when it comes to biodiversity, flora, fauna, and fungi should be on an equal footing.

Also in 2021, the International Union for Conservation of Nature welcomed a new committee: the Fungal Conservation Committee. This group, made up of renowned experts from several countries (including the Portuguese experts Cátia Canteiro and Susana Gonçalves), wants to raise awareness of the importance of fungi, highlight the need to protect them, and promote conservation actions. Some of its members are also responsible for the assessment and validation of the risk status of fungi species on the IUCN Red List.

Expanding this list is a task that fungi experts can help with (individually, in scientific groups, or through organisations dedicated to the subject). The IUCN encourages this input from anyone who wishes to share information on species that may be under threat globally and should therefore be assessed. Learn about the criteria to be applied and how to contribute.