Why are fungi so important?
Mycology, the study of fungi – its importance to us and to ecology and conservation is perhaps unsurpassed by any other branch of the biological sciences. Whether you simply enjoy the fruits (bread and beer, wine and cheese) of the labour of countless yeast cells, savour the taste of freshly fried mushrooms, benefit from antibiotics sequestered from moulds, curse the loss of garden plants through dampening-off and blight, regret the wholesale loss of much loved trees such as ash and elm, value the horticultural therapy of nutrient rich friable leaf mould, or with wider horizons, applaud the recycling of biomass worldwide and their intimate symbioses with higher plants, then you know mycology matters.
I think we are all born mycologists. A child is naturally fascinated by the shapes and colours of mushrooms and toadstools. Their often diminutive size adds to their appeal and the satisfaction of finding them. So fungus forays have become one of the most popular events organised by environmental groups attracting all ages and helping to introduce children to the natural world and how it works. It is not uncommon for autumn forays to attract over 100 forayers and applying the general rule of one species per forayer it’s easy to see that collections of 100+ species are not unusual.
What exactly do participants gain from a foray? For a start the sight of so much colourful diversity amassed on tables in a village hall is undoubtedly arresting and memorable. No other branch of biology rewards a few hours of amateur searching with such diversity. Regular foray sites boast species lists of 500-1000 and Esher Common and Bagshot Heath SSSI in SE England holds the record at over 3,300 species, that’s over 25% of the British list.
New species to science found everyday!
Nobody knows how many fungi there are worldwide. Currently mycologists describe roughly 1,500 new to science each year but with an estimated of 1.5 million species to document, this process will take a millennium to complete. And even here in the UK which is mycologically relatively well known, 460 species new to science were discovered between 1980 and 1989. Sometimes these new taxa are surprisingly abundant in particular habitats eg Russula torulosa, a beautiful brittle gill which carpets the pine plantations at Newborough on Anglesey, first discovered new to Britain by local amateur mycologist, Charles Aron in 1998 .
The simple shape of fungi provides a convenient opportunity to explain form and function, especially reproduction. A toadstool is simply the fruiting part of the fungus organism designed to accommodate the maximum number of spores per cap. This is achieved by gills, pores and spines of agarics, boletes and hedgehog fungi respectively. Then the numbers game kicks in again – spore production is astronomical with an average mushroom producing 40 million per hour for two days. The Giant Puff Ball (Calvatia gigantea) holds the record with a large fruiting body accommodating roughly 7 million, million spores. Children love big numbers. They also love little numbers and when you explain that each spore is only a few thousandths of a millimetre in diameter and yet some fungi ‘shoot’ them into the air up to 5 cm, which is like a human being fired from a cannon and landing 10 kilometres away, then fungi begin to sound ‘cool’.
A world intertwined by fungal hyphae
If toadstools are the fruit where’s the rest? Hidden in their favoured substrate – soil, leaf, wood – in the form of wefts of millions of branched hyphae, each no more than 5-20 thousandths of a millimetre wide, elongating by up to 6mm an hour exploring the environment for food in the form of organic carbon. In this way an individual fungus can create a kilometre of fresh hyphae in a day. Through their flexible walls and permeable membranes hyphae are akin to supple syringes, secreting enzymes and absorbing products of the digestion of macro-molecules such as cellulose and lignocellulose, the two most abundant carbon compounds on the planet. Most heterotrophic forms of life including most animals and bacteria cannot digest cellulose, making fungi essential for recycling nutrients. Without recycling life on earth would cease. Vital stuff, important for everyone to appreciate.
And then there are the symbiotic fungi – they come in a huge range of size and form and include lichens, the most widespread group of earth dwellers at least at the resolution of the human eye. Lichens are an amalgam of fungi and either algae and/or cyanobacteria and are thought to be among the oldest macroscopic mutualisms on the planet. They may well have kick-started the colonisation of life on land by creating a biofilm on formerly bare surfaces. Then there are the endophytic fungi including the truly microscopic Glomerocytes which we now appreciate occur inside the living tissues of virtually all plants assisting with nutrient acquisition as well as gifting them immunity to many disease organisms. Extensive formations of macrofungi such as brittle gills, milkcaps, boletes, Cortinarioids and hundreds more form so called ectomycorrhizal associations with the roots of many familiar plants including all the dominant tree species of temperate regions eg oak, birch, pine and spruce.
Whatever their size these fungi benefit their partners significantly, enhancing the capacity of root systems to take up water as well as nitrogen and phosphorus. Without the association it seems that many species of higher plant would not survive, especially on poorer soils or under exacting circumstances. In return the host plants transfer up to 25% of their photosynthetic output into their roots to sustain the populations of vital fungal hyphae. That’s a huge amount of primary production being diverted and speaks volumes for the relative importance of fungi to forest trees.
This is an ancient relationship. Fossils of the first land plants, from the Devonian Period, some 400 million years old, display tell-tale hyphae-like impressions within their tissues and it may well be that such infection and co-operation was essential for plant life to cope with the exacting conditions of life on land rather than the sea. Roots may be viewed as repositories for fungi – that’s how important fungi were and still are.
The largest organism on the planet and a mere 2,400 years old
But understanding how all this works in nature is among the hardest tasks for ecologists and mycologists. Hyphae are difficult to identify and don’t necessarily belong to the nearest fungus at ground level. Their extent can be enormous (900 hectares in the case of one genetically distinct individual Honey Fungus in Oregon) and their life spans counted in hundreds of years (an estimated 2,400 years for the Oregon monster). So understanding what’s going on at one point in time and space and from there extrapolating the significance of fungi at ecosystem and evolutionary levels is a challenge.
Fungi as indicators and conservation priorities
It’s a challenge we can’t afford to ignore and answers are urgently needed to inform fungus conservation. Fungi, both mycorrhizal and saprotrophic, forest denizens and grassland specialists, are sensitive to changes in the environment from climatic oscillations to agricultural upheavals, from acid rain to changes in commercial forestry. Targeted surveys and analysis of historic foray-finds show that fungi are declining in quantity and diversity.
The same is true for lichens, a group which has proven its worth as a bio-indicator of environmental change. Quantifiable negative correlations at individual, species and community levels are all demonstrable between number and biomass of lichens and loss of habitat such as ancient woodland and increasing atmospheric pollution. Lichen diversity now plays an important part in site assessment for ecological continuity, air quality and nature conservation.
And yet in Britain not a single SSSI exists specifically for non-lichenised fungi and the first full-time post for a conservation mycologist was only created in 2010. It has befallen the NGOs listed at the end of this article to take up the mycological cause with assistance from the Royal Botanic Gardens at Kew and Edinburgh as well as CABI Bioscience. They have helped highlight almost 100 species of fungi of sufficient conservation concern to warrant Biodiversity Action Plans. Additionally, the British Mycological Society has produced two provisional conservation assessments – a Red Data List of 380 species of non-lichenised fungi and an inventory of over 500 important sites for non-lichenised fungi. In 2008 Plantlife published an excellent strategy (entitled ‘Saving the Forgotten Kingdom’) on behalf of a range of interested mycological partners. It is significant that several European countries have official Red Lists for non-lichenised fungi and their conservation attracts more attention than here in the UK.
Finally let’s return to the foray where the fruits of decay and symbiosis surely brighten our perception of the living world as a dynamic system in which many if not most of the connections are fungal and have been ever since life emerged from the sea and colonised land. Outwardly simple but biochemically so complex, fungi are truly the ultimate ecological facilitators. They underpin ecosystem functioning and ultimately ecosystem services and they matter to us all.
Find out more
British Mycological Society www.britmycolsoc.org.uk – foremost organisation for the study and survey of non-lichenised fungi in British Isles and the largest mycological society in the world – publishes excellent quarterly magazine, ‘Field Mycology’ and organises workshops, field trips and lectures.
British Lichen Society www.britishlichensociety – outstanding combination of amateur and professional energy which has resulted in lichens being relatively well understood in this country both taxonomically and ecologically. Much of that knowledge has been channelled into lichen survey and conservation. The society arranges field trips and workshops and publishes a Bulletin and a scientific journal, ‘The Lichenologist’.
Association of British Fungus Groups www.abfg.org – supports amateur forayers, and publishers the quarterly magazine ‘Forayer’.
Plantlife www.plantlife.org.uk – an influential plant conservation society which takes fungi seriously too.
The following bibliography is in alphabetic order of primary authors:
Gilbert, O. (2000) Lichens. Published by Collins and a very worthy title in the New Naturalist Series.
Marren, P. (2012) Mushrooms. Published by British Wildlife Publishing, Dorset. – a vivid introduction to the world of fungi, compiled with infectious enthusiasm and conservation insight by one of our foremost natural history writers.
Spooner, B. and Roberts, P. (2005) Fungi. Published by Collins. One of the finest titles in Collins’s unrivalled New Naturalist Series this volume covers everything from evolution to economics to ecology. Written in an accessible style this is a tour de force by two of the country’s leading mycological experts who until their recent retirement worked at Kew Royal Botanic Gardens.
Buczacki, S. and Shields, C. (2012) Collins Fungi Guide. HarperCollins London. Comprehensive and easy to use this handy field guide describes and illustrates 2,400 species.
Courtecuisse, R. and Duhem, B. (1994) Mushrooms and Toadstools of Britain and Europe. Collins Field Guide, Collins, London. Another excellent field guide describing 1750 species (including European species) though poor on bracket fungi and some other groups such as puffballs and jelly fungi. Illustrations superb.
Dobson, F.S. (2000) Lichens. An Illustrated Guide to the British and Irish Species. 4th revised colour edition. Published by The Richmond Publishing Co. Ltd., Slough. An attractive field guide with excellent photographic images, authoritative text and good selection of most widely occurring species.
Phillips, R. (1981) Mushrooms and Fungi of Great Britain and Europe. First edition published by Pan Books, London. 2nd edition published in 2006 by Macmillan. Wonderful colour photographs. Covers a large, carefully chosen list of fungi.
Sterry, P. and Hughes, B. (2009) Collins Complete Guide to British Mushrooms and Toadstools. HarperCollins, London. Comprehensive and very well chosen set of fungi, very well illustrated with photographs.
Boertmann, D. (2010) The genus Hygrocybe. 2nd revised edition. The essential identification guide for this important genus of grassland fungi. The British Isles hold more species and the best sites for this group than any other European country and they are now regarded as prime indicators of sites of conservation interest.
Kibby, G. (2012) The genus Russula in Great Britain. Self published.
Other monographs published by Kew are available eg Hebeloma, Agaricus, Boletes – these are usually well illustrated and essential for critical identification work.
Web Sites specifically for identification of Fungi and Lichens:
British Lichens www.britishlichens.co.uk very useful, user-friendly site
Cybertruffle www.cybertruffle.org.uk outstanding international fungal identification site with lots of links
Fungi Online www.mykoweb.com