Come and be part of a global voice for wild plants and fungi
This autumn, help us find Britain’s most colourful and important fungi – waxcaps.
Fungi are crucial to nearly all life on Earth, but they are not given the recognition and investment they deserve. Will you join our mission to change that?
Our corporate partners benefit from 35 years of experience in nature restoration so they can achieve real impact.
Become a Plantlife member today and together we will rebuild a world rich in plants and fungi
Recent studies have revealed that there’s so much fungi out there that we don’t know about.
But how do we know this? Plantlife’s Rachel Inhester, from our science team, tells us why.
This incredible fact from the Kew report, ‘State of the World’s Plants and Fungi 2023’, highlights just how much there is to learn when it comes to fungi. That was certainly my first thought when I read this statement. It’s exciting to think of all the discoveries we have yet to make, and it gives an indication as to the huge amount of work ahead of us, to find and classify such a large number of unknown species. The report goes on to estimate that there are between 2-3 million species of fungi in the world, and as of yet, only 155,000 of those species have been formally named!
Fungi can be difficult to detect for a number of reasons:
As I was contemplating just how little we know about these extraordinary organisms; another thought came to mind. How can we estimate that 90% of fungal species are unknown to science? How did we come up with that number? In other words, how can we know what we don’t know?
Well, it turns out, that to arrive at such an estimate, you first need a team of fungal specialists, known as mycologists, and then you need the time and capacity to critically evaluate all the current knowledge on the topic so far. It was certainly no simple undertaking!
Past methods of calculating the number of fungal species, were not without issue, so the team of experts definitely had their work cut out for them. Previous estimates couldn’t be completely relied upon on their own. Sampling techniques varied and some fungal groups were not considered in certain studies. Some reports were simply outdated due to the discoveries that have been made since they were first published.
It’s important that we try to speed up this process so that we can understand the fascinating world of fungi around us. Fungi are interconnected with nearly all life on earth. They can improve nutrient uptake of plants, improve the immunity of their plant hosts against pathogens, they are biomass decomposers, and some species are used to make medicines [1].
The team of specialists decided to focus on 4 key academic areas to better estimate the number of expected species. These research areas were scaling laws, fungus to plant ratios, actual vs previously known species and DNA based studies.
Organisms are classified into 8 main levels or ‘taxa’. From highest to lowest, these taxa are: Domain – Kingdom – Phylum – Class – Order – Family – Genus – Species. This is a way of organising organisms into groups which become more inclusive with every level. Let’s use the Fly Agaric fungi as an example. At species level we simply have Fly Agaric (Amanita muscaria). The Fly Agaric is an individual species, but individual species can belong to a larger group, or genus, in this case the genus Amanita. A genus is a grouping of similar species which all share a common ancestor. The groupings, or taxa, get progressively larger as you move up each level until you reach the levels of Kingdom and Domain. The Fly Agaric is part of the Fungi Kingdom which includes all other fungal species.
Scaling law studies aim to predict species diversity by looking at patterns in the numbers of ‘higher taxa’ and the number of known species in each.
In this case, information from the level of phylum (the third taxa) to genus (the seventh taxa) was used. Patterns in the numbers of these ‘higher taxa’ were compiled to predict fungal species diversity. Previous studies were assessed by the fungal experts, who adjusted the estimates to include recent discoveries and accurate numbers of known species.
Fungus to plant ratios have been estimated in multiple studies over the years and for a variety of habitats. Therefore, if we know the number of plant species, we can make a pretty good estimate as to the number of fungal species.
However, the fungal experts were still faced with challenges when examining previous research. Studies varied in how they calculated the ratios to begin with. Some only considered fungi with a known association to plants and other studies were much broader. Coupled with the fact that lots of fungi can be difficult to detect and may have no association with plants whatsoever, a lot of the predictions were considered an underestimate. On evaluating earlier research, the specialists felt that a ratio of 5:1, of fungi to plant species, in temperate areas and 4:1 in tropical locations, was more accurate than previous estimates.
Some species of fungi can be difficult to differentiate. This can cause an underestimation of species numbers as multiple species are occasionally classified as one and the same. The fungal experts examined a study which had investigated this in detail where they concluded that there were 11 times as many actual species compared with previously known species. Varying definitions of exactly what a species is, creates difficulty with this method of estimation.
DNA based methods have been an incredibly powerful tool in documenting fungal diversity around the world. A single sample can allow scientists to sequence the DNA of whole communities of fungi. These samples can come from a variety of places, including soil and deadwood. The samples are then analysed and any DNA within the sample is extracted and sequenced.
This DNA gives us a list of all the fungal species found in a sample, including species which we can’t even see, providing us with a more accurate representation of fungal species numbers.
For Kew’s report, it provided the final piece of the puzzle in answering the question of ‘how many species of fungi do we think there are globally?’.
Using all the information and research available to them, the fungal experts refined their predictions and came up with an estimate of 2.5 million species of fungi worldwide! [2]
So there really was a lot of work that went into this seemingly impossible estimation. As it stands, this estimate reveals how many species we have yet to discover.
At this time, around 2,500 new species of fungi are identified and described each year. And if the above estimate is accurate, that would mean waiting 750-1000 years for us to find and describe the rest. [2]
As we discover more species, we shall hopefully uncover more benefits of the fungi around us, as well as conserving as many species as possible before we potentially lose them forever.
Fungi underpin the health of our environment and are key to resolving the climate, ecological and societal challenges we face. Your donation could help increase understanding of fungi and get them the support they need.
Here we delve into this mind-boggling realm to discover ten of weirdest, wackiest and most wonderful facts from the world of fungi!
Our specialist botanical advisor Sarah Shuttleworth revisits her favourite fungi find – the rare Blue Tooth fungus.
Britain is home to some of the most important waxcap grasslands in the world. However many species are becoming rare and declining; they need identifying and protecting.
We will keep you updated by email about our work, news, campaigning, appeals and ways to get involved. We will never share your details and you can opt out at any time. Read our Privacy Notice.
