Mushrooms are fascinating fungi that have been valued by humans for thousands of years as both food and medicine. But how many different types of mushrooms are there in the world? And how many individual mushrooms exist at any given time? Getting accurate estimates is challenging, but here is an overview of what we know so far about the global mushroom population.
The Number of Mushroom Species
There are approximately 14,000 to 22,000 known species of mushrooms worldwide. The estimated totals vary widely between different sources, mainly because new species are still being discovered all the time, especially in tropical regions. About 10,000 species have been formally classified and described by mycologists (scientists who study fungi), but there may be over 12,000 more that have yet to be documented.
The majority of mushroom species are basidiomycetes, which produce spores on gills or pores. Other groups like ascomycetes (cup fungi) and zygomycetes (pin molds) contain far fewer mushroom-forming species. Most known species occur in the deciduous forests of the Northern Hemisphere, which have been more thoroughly studied than tropical areas.
Geographic Distribution of Mushrooms
Mushrooms can be found on every continent except Antarctica. But the vast majority of species occur in moist temperate and tropical forests in Asia, Europe, North America, South America, and Africa. These continents, along with Australia, are considered megadiverse regions with extremely high numbers of plant and animal species as well as fungi.
Certain countries stand out as having the most mushroom diversity. China, Japan, Korea, India, Thailand, Mexico, Colombia and Brazil all have over a thousand recorded native species. Russia may have over 3000 types. The United States and Canada combined have at least 3000 species. However, mycologists estimate that only about 10% of fungal diversity has been described globally, so the true numbers for most countries are likely much higher.
Estimating the Mushroom Population
Determining the total global population of mushrooms at any given time is even more challenging than counting species. Mushrooms produce ephemeral fruiting bodies that may only last for days before deteriorating. And most species spend the majority of their life cycle underground as thin threads called mycelium.
One method used by mycologists to estimate mushroom population sizes is to measure their biomass per unit area in different habitat types. Studies have found an average of around 300-500 kilograms of mushroom biomass per hectare of temperate forest. Tropical forests tend to have higher fungal biomass approaching 1000 kg/hectare.
If we very roughly extrapolate these density figures to global forest cover, we can generate a ballpark estimate for the total mushroom biomass on Earth:
| Habitat | Area (billion ha) | Average mushroom biomass (kg/ha) | Estimated total biomass (billion kg) |
| Temperate forest | 1.04 | 400 | 416 |
| Tropical forest | 1.76 | 750 | 1,320 |
| Total | 2.80 | 1,736 |
According to these rough estimates, the total global biomass of mushrooms at any given time is around 1.7 trillion kilograms. That’s over 1.7 billion metric tons of fungal fruiting bodies blanketing the Earth! Of course, the actual figure may be quite different – potentially orders of magnitude lower or higher. But this calculation gives us an idea of the scale and ubiquity of mushrooms around the world.
Threats to Mushroom Populations
In the past, the plentiful mushroom population was able to withstand human picking without threat to diversity or ecosystem health. But habitat loss from development, agriculture, and climate change is putting increasing pressure on fungi worldwide. Estimates suggest 10-50% of mushroom species may be threatened with extinction in the coming decades if conservation efforts are not made.
Some of the major threats facing global mushroom populations:
- Deforestation and habitat fragmentation
- Pollution from industry, traffic, and intensive farming
- Invasive species that disrupt native fungal communities
- Over-harvesting of wild edible mushrooms
- Climate change altering habitat conditions and mycelial networks
Protecting the remarkable diversity and abundance of mushrooms around the world requires preserving old growth forests, regulating pollution, controlling invasive species, sustainably harvesting mushrooms, and reducing CO2 emissions. With informed conservation policies, this valuable global fungal resource can thrive for generations to come.
Conclusion
Determining the exact number of mushrooms worldwide is probably impossible given their microscopic size, underground lifestyle and constant flux. But based on available data, there are likely between 14,000 to 22,000 species globally and around 1.7 billion tons of mushroom biomass at any given time. While abundant, mushrooms face increasing threats from habitat loss and climate change. Conserving intact forests and sustainable harvesting practices will help ensure these ecologically vital fungi continue to thrive.
