Thursday, 6 July 2017

Plotting fungi distribution against host distribution

Tom May
Royal Botanic Gardens Victoria


Many larger fungi such as mushrooms are associated with particular plant hosts. Some form mutualistic partnerships with trees (mycorrhizas), others are decomposers of wood or litter.

Fungimap records provide interesting comparisons of the distribution of host plant and fungus. We can use the spatial portal of the Atlas of Living Australia to map individual species, and to map several species at once, a very useful feature. Here, we use the co-mapping ability of the ALA Spatial Portal to investigate the distribution of two Fungimap target species, Cortinarius metallicus and Craterellus cornucopioides.

Mapping Cortinarius metallicus

Cortinarius metallicus growing under Nothofagus
(note the characteristic leaves of the tree on the mushroom's pileus).
Image: Geoff Lay CC BY-NC-SA.
Cortinarius metallicus is a distinctive mycorrhizal fungus that is always reported in close association with Myrtle Beech Nothofagus cunninghamii. Sporophores of the fungus are found under the canopy or very near Myrtle Beech trees, where the mycelia (growing portion) of the fungus in the soil wraps around the fine roots of the tree, providing an interface for a reciprocal exchange of nutrient between tree and fungus.

In the Spatial Portal of the ALA we can see that the overall distribution of the fungus spans Victoria and Tasmania (map not shown here).





Map of records of Cortinarius metallicus in Victoria
 in the Atlas of Living Australia (June 2017).
In Victoria, two dots seem more isolated from the main distribution (which is in the Central Highlands to the east of Melbourne), one dot is to the west and one is to the east. Perhaps these outlying occurrences are incorrect records or maybe there have been mistakes in assigning the geographic coordinates. Outliers that are several 100s or 1000s of kilometres away from the main distribution would be suspect. However, in this case, from the map alone, it is difficult to be sure if any dots are in the wrong place as none sit more than about 100 km away from the main distribution in the Central Highlands.





In the ALA spatial portal, mapping Cortinarius metallicus over Nothofagus cunninghamii provides an interesting perspective. Co-mapping shows that both host and fungus are found widely in Tasmania and in certain areas within Victoria. The scattered isolated green dots for Myrtle Beech outside of the main areas of distribution, especially seen in Victoria, are usually records of cultivated trees in parks and gardens.


Distribution in Tasmania of Cortinarius metallicus (red dots)
mapped over Nothofagus cunninghamii (pale green dots),
using the spatial portal of the Atlas of Living Australia (June 2017)


Closer inspection of the fungus records (red dots) in Tasmania shows that some of the dots are well outside of the areas where Myrtle Beech is found (pale green dots). For example, there is an isolated red dot in the lower east coast of Tasmania. Inspection of the record data shows that the original record is in fact from the Tarkine region of northern Tasmania, and there has been a mistake in assigning the geographic coordinates. In addition, the two records in the sea off the west coast obviously have mistakes in their geographic coordinates.

Distribution in Victoria of Cortinarius metallicus (red dots)
mapped over Nothofagus cunninghamii (pale green dots),
produced in the spatial portal of the Atlas of Living Australia (June 2017)









In Victoria, there is an isolated record from north-east of Melbourne, in an area where there is no Myrtle Beech. This record was checked against the original locality data and is not an incorrect geographic coordinate. In a case like this, we inspect any images associated with the record; but for this record, there is no image. Given that all other records of the species are in very close association with Myrtle Beech, the record must be regarded as dubious, and will therefore be marked as such in the Fungimap database. When Fungimap data are next uploaded to the ALA dubious records such as this will not be included. The second somewhat isolated record in Victoria, from the Baw Baw plateau, to the east of the main distribution in the Central Highlands, is associated with Myrtle Beech, and there is no reason to doubt the record (and a further record with an image was recently received from that area, as reported in A virtual foray in Cool Temperate Rainforest).


Mapping Craterellus cornucopioides

Craterellus cornucopioides
Photo: Richard Hartland. CC BY
A Fungimap target species that has been suggested as having a strong association with Myrtle Beech is Horn of Plenty Craterellus cornucopioides. This name is from the Northern Hemisphere. It would not be at all surprising if the local fungus turns out to differ from the Northern Hemisphere species. For the moment we refer to it as Craterellus cornucopioides. The fungus occurs from Tasmania to Queensland. FunGuild (a database on the trophic status of fungi, i.e. whether particular fungi are decomposers, mycorrhiza-formers, parasites etc.) lists the genus Craterellus as highly likely to be ectomycorrhizal.


Distribution in south-eastern Australia of
Craterellus cornucopioides (red dots) mapped over
Nothofagus cunninghamii (pale green dots),
produced in the spatial portal of
 the Atlas of Living Australia (June 2017)

Plotting Craterellus cornucopioides (red dots) against Nothofagus cunninghamii (pale green dots) as a potential host (in Victoria and New South Wales) shows that at a broad scale, where Myrtle Beech is present, most records of the fungus seem to be within the distribution of Myrtle Beech. However, the fungus also occurs in areas very distant from Myrtle Beech, in the east of Victoria and in coastal New South Wales, as well as Queensland.

Another species of Nothofagus, Nothofagus moorei, occurs in New South Wales and southern Queensland. In New South Wales this Nothofagus is restricted to the Barrington Tops and areas to the north. The northernmost record of C. cornucopioides in New South Wales is in fact from the Barrington Tops, although there is no mention of the presence of Nothofagus. However, all other reports of C. cornucopioides from New South Wales are to the south of the distribution of Nothofagus moorei.









Distribution in Victoria of Craterellus cornucopioides (red dots)
 mapped over Nothofagus cunninghamii (pale green dots),
produced in the spatial portal of  the Atlas of Living Australia (June 2017)
Closer inspection of the Victorian occurrences of Craterellus cornucopioides shows that some dots that fall over the Mrytle Beech distribution, when mapped at a wide scale, are in fact are close to, but not co-incident with the distribution of Myrtle Beech, when mapped at a finer scale. There are also occurrences of the fungus to the east, far from the current distribution of Myrtle Beech, and so the fungus is able to grow in a much wider overall range compared to the tree. If Craterellus is indeed mycorrhizal, it remains to be seen which trees in particular it is associating with. Observations of exactly which types of trees the sporophores occur under will be useful in determining this. Co-mapping certainly shows that it is not a strict associate of Nothofagus.


The uses of co-mapping

Co-mapping of host and fungus is a useful tool for understanding the strength of association between particular fungi and plants, and also for detecting erroneous records, either due to misidentification or to incorrect geographic coordinates. Co-mapping also suggests areas to explore where the plant is present but the fungus has not yet been reported. For example, Cortinarius metallicus has not yet been reported from three areas in Victoria where Myrtle Beech is present: The Otways, the Strzelecki Ranges and Wilsons Promontory - so look out for this distinctive fungus in these areas.

Tom May
Fungimap / Royal Botanic Gardens Melbourne

Friday, 23 June 2017

To Foray or to Forage?

by Alison Pouliot

[Reprinted from Fungimap Newsletter 57. This article is the Introduction to a special issue of the Newsletter on the topic of edibility.]


Do we really want to see mushroom collecting
regulated in Australia?
Image Alison Pouliot.


According to Pliny, foragers seeking edible mushrooms should steer clear of serpents' dens as their breath renders mushrooms toxic. Despite his counsel, great flourishing crops of poisonous Yellow Stainer mushrooms (Agaricus xanthodermus) are becoming commonplace on urban nature strips, sans serpents. This special issue of Fungimap Newsletter addresses the germane yet contentious theme of foraging for wild edible mushrooms in Australia. What are the risks and benefits of foraging for wild edible fungi? What position should Fungimap take regarding the increasing number of requests for information about the edibility of fungi? And what can we learn from responses to the rapid rise of foraging in similarly traditionally mycophobic nations such as the UK and the USA in recent decades?





Since its founding in 1996, Fungimap has focussed on the scientific collection of fungus data with the aim to map the distribution of Australian macrofungi and contribute to knowledge about fungal ecology, life histories and conservation. A core part of the activities of Fungimap is identification of the numerous records that are submitted each year as part of the ongoing mapping scheme for Australian fungi, focussed on target species, but also covering other fungi that are recognisable in the field. All images submitted with records are checked, and data are also checked via inspection of maps to detect outliers that might be dubious records. In addition to records of fungi, Fungimap is increasingly receiving requests for identification in relation to edibility (a typical email is a couple of images with the request: ‘Can I eat this mushroom?’). In this special issue, various authors share their experiences and views on the potential perks and perils involved in foraging for wild edible fungi, and how Fungimap should respond to this growing interest.

People have been eating edible fungi for thousands of years – potentially tens of thousands of years – the first possibly being Aboriginal Australians. In dozens of developing countries wild edible fungi provides an important food source for alleviating hunger and poverty. In contrast, wild edible fungi are eaten predominantly as a gourmet speciality in the developed world including Australia. However, relative to many other countries (e.g. continental Europe, particularly Slavic countries, Russia and some African, South-east Asian and South American cultures) little is known about the edibility of Australian fungi.

Poisonings from the ingestion of toxic mushrooms do occur in Australia, most notably and lethally from the Deathcap (Amanita phalloides). Cultural issues also come into play here. Despite stronger foraging traditions in other countries, knowledge about the edibility of fungi does not always translate to Australia where foragers encounter different species and environments. Moreover, unlike European fungus field guides, it is only in the rare exception that Australian guides indicate the edibility of a species. The disparity between the level of public knowledge about wild edible fungi and that required for safe foraging is an issue of great concern to Fungimap.

In Australia, other than Aboriginal use of fungi for which records are scant, interest in fungi has predominantly been among field naturalists who mostly take a scientific approach. The Field Naturalists Club of Victoria (FNCV) has held fungus forays since its founding in 1880. Interestingly, early reports from the FNCV journal, The Victorian Naturalist, reveal that some field naturalists also collected fungi as food. However, given the unstable taxonomy of Australian fungi and growing awareness of conservation as from the 1970s, field naturalists today mostly only pursue fungi as a scientific interest. Nevertheless, in countries such as Sweden, foraying and foraging often occurs simultaneously and many folk consider them to be mutually compatible, encouraging a wide appreciation of the many values of fungi. Much can be understood about the compatibilities and conflicts between foraying and foraging by looking beyond our shores. The rapid increase in foraging in the UK and USA and the consequent environmental and social issues could inform an Australian response and protocol. Reviewing these situations could allow us to anticipate potential problems, hence minimizing environmental damage, social conflict and the need for regulation by fostering more sensitive and sustainable foraging practices.

Further to human health risks associated with foraging, potential conservation issues, particularly from the commercial exploitation of wild edible fungi, require informed discussion. Lack of knowledge about species distributions and life histories make it difficult to predict potential impacts on popularly harvested species and environments, hence the need for a precautionary approach. Australia currently has no guidelines or recommendations for the collection of wild edible fungi, although all fungi are implicitly protected on public land (being lumped under plants if not specifically mentioned in legislation). Biodiversity conservation in Australia, indeed globally, has focussed on the protection of plants and animals, with fungi being largely overlooked. All current conservation efforts in Australia stem from NGOs, community groups and interested individuals. Recent initiatives such as the Global Fungal Red List are making important inroads into the recognition of fungi in conservation. Could interest in wild edible fungi also stimulate greater interest in the ecology and conservation as has been the case with many hunters and fishers?

Two of the more commonly foraged species,
Lactarius deliciosus and Suillus luteus
are both often sought from pine plantations.
Image Alison Pouliot.
The issue opens with two articles by fungus enthusiast and field guide author Patrick Leonard. He provides a fascinating historical summary of the various uses of fungi by Aboriginal and early European Australians. His humorous account of the development of the commercial mushroom industry that produced a mushroom (Agaricus bisporus) that tastes like "wet cardboard" might be a stimulus, he suggests, for a return to foraging. He lists several known edible Australian species, dispels some myths and provides some cautionary tips for foragers, and concludes by reminding us that despite the pleasures and benefits of foraging, there are "far too many of us to indulge in it regularly".

Leonard's second article focusses on the issue of whether foraging poses a conservation threat to fungi. As very few people forage for edible fungi in Australia it is unsurprising that there is little research to assess potential environmental effects. Hence, Leonard looks into research further afield – to China, the USA and Europe – to discover that commercial harvesting has led to a decline in fungus populations. Leonard addresses four major issues which he summarises as questionable sustainability, collateral damage, conflicts with local residents and habitat damage. While a commercial licensing system exists in Australia, Leonard outlines its failings particularly the challenge of determining sustainable yields and a lack of monitoring and policing. He concludes that regulation is necessary due to declining fungus populations .

Leonard provides a thoughtful assessment of many aspects of the argument while other contributors strongly represent a particular stance. A keen forager, Kim Nguyen insists that conversations about edibility need to be had among the mycological community. She discusses the various approaches to public queries regarding edibility among fungal studies groups and mycological societies in Australia and beyond. Furthering the argument for foraging, data administrator of the iFungi Au iPhone app, Gregg Cook, acknowledges the risks involved for uninformed foragers but considers that "is it is irresponsible or negligent" to withhold knowledge about the edibility or toxicity of a species.

Chef, George Biron writes of his passion for forging for wild edible fungi but also the dangers, noting that a "short half day foray" is not sufficient to train someone to safely identify edible mushrooms. Biron recognises the growing interest in foraging for wild fungi and encourages the production of an "ecologically sound" guide and accreditation courses. He suggests that accredited commercial foragers would not only become the preferred providers for provedores and restaurateurs, but that knowledge gained through courses would lead to greater respect for environments where fungi grow. In a more lighthearted article, self-confessed "boletivore-Biron" introduces the French notion of "terroir" as potentially influencing the flavour of Australian grown Boletus edulis. Like Nguyen, he also sees a link between foraging and conservation.

Representing the other end of the foraging spectrum, mycologist Genevieve Gates begins her article by stating the difficulty in defining any fungus as definitively edible due to the differing responses of individuals (e.g. allergic reactions) to other types of supposedly edible foods such as shellfish and strawberries. Further to poisoning risks, Gates strongly conveys her belief that that fungi exist for species other than Homo sapiens and human foraging would not be sustainable and could not be regulated in an Australian context.

There are various arguments against foraging that mostly centre around conservation concerns and poisoning risks. Mycologist, Tom May provides an insightful overview of his observations of the general public's poor ability to accurately identify mushrooms. As the senior mycologist at the Royal Botanic Gardens Victoria and an honorary consultant to the Victorian Poisons Information Centre, May is probably the most experienced person in the country in identifying specimens provided by the public and advising on cases of fungal poisoning. May cites several incidents of mis-identification where major identification features such as morphology, colour, spore colour, habitat and other conspicuous characteristics were overlooked. In reference to specimens brought to the herbarium by the general public, he comments, "Indeed, it is quite rare for the identification to be correct!". His concerns echo those of mycologist Ian Pascoe who commented in the 1980s that the public are often poor observers and unlikely to have the necessary skills to differentiate species. However, May is not steadfastly opposed to foraging but encourages a cautious and slow approach – an "apprenticeship" in learning how to accurately identify fungi.

How might restricted species such as Cyttaria gunni
be affected by increased interest in foraging?
Image Alison Pouliot.
Other authors relate their personal experiences of foraging. Sarah Lloyd and partner Ron have sampled various fungi that grow on their Tasmanian property with mixed reactions and lament the loss of knowledge about the edibility of fungi held by the Traditional Owners of the region. While not specifically focussed on edible fungi, in their article, Lloyd and mycologist Sapphire McMullan-Fisher reiterate the connectedness of nature including fungi and provide a set of codes for ensuring that the environment is not damaged through the collection of fungi. Masters of BioSciences student, Grace Boxshall, is conducting research on the poisonous species, Agaricus xanthodermus (and its allies), the species responsible for most poisonings in Victoria. The results of her work should provide valuable insights into the phylogeny for Australian representatives of the genus and a better understanding on variations in toxicity within the genus. Boxshall puts out a call to the public to assist in her research by submitting sightings of species of Agaricus, Chlorophyllum and Macrolepiota through FungiSight.


People seek and relate to fungi in many different ways. Mycologists study the ecological and evolutionary significance of fungi to situate them within larger schemes of life. Naturalists make lists of species to understand fungal ecology and geography. For visual artists and aesthetes, form and colour are the focus. Foragers seek edible mushrooms. All of these approaches contribute to the understanding and appreciation of fungi. The trick might be to focus on the common ground between them, so as to ensure a sensitive and sustainable approach that will minimise environmental damage, poisoning risk and ensure the ongoing flourishing of Australia's rich and unique mycota.

Friday, 9 June 2017

A virtual foray in Cool Temperate Rainforest

Most Fridays I sit down with Fungimap volunteer Graham Patterson in the Fungimap office and go through the week's emails, checking the identification of fungi records that have been submitted to Fungimap.

Each week in the Fungimap email in-box there is a mix of batches of records from long-time recorders, often with many records; but some emails with one or a few records. Long-time recorders usually supply a spreadsheet with locality and other details for the fungi they have spotted. There are also new contacts from people just starting to record fungi. These deliberate records are mixed in with enquiries about fungi from around Australia in relation to edibility, toxicity, beauty, weirdness and danger. Many of the latter enquiries do not have locality information. However, as well as providing brief answers to the enquiries, if an image is supplied, and we can identify the image and it is an interesting record, we request additional locality information.

Cortinarius metallicus growing under Nothofagus cunninghamii.
 Photo: Eileen Laidlaw, used with permission, all rights reserved.
Recently, one batch from Eileen Laidlaw stood out as an interesting set of species. Eileen's records came from the vicinity of the car park at Mt St Gwinear, including along the upper reaches of South Cascades Creek (Baw Baw Plateau, Victoria). There were a number of photos attached to the email. Even before reading the record spreadsheet I could see that some of the fungi were from Myrtle Beech (Nothofagus cunninghamii) Cool Temperate Rainforest - because I spotted the distinctive blue pileus of Cortinarius metallicus among the attached images. This species was originally placed in the genus Rozites, due to the presence of a distinct annulus (ring) on the stipe, but Rozites is now considered a synonym of Cortinarius. Closer inspection of the photo revealed a scatter of the distinctive small, crenate (scalloped-edged) leaves of Myrtle Beech, and the information in the habitat column of the record sheet confirmed the connection: 'On soil accumulated on a granite rock, surrounded by Myrtle Beech and Mountain Tea Tree'.

Cortinarius metallicus is a Fungimap target species, distinguished by the blue colour, the viscid (slimy) pileus surface and the stipe with annulus. So far, it has only been found in association with Myrtle Beech, in Tasmania and Victoria. The only species that it could be confused with is the widespread Cortinarius rotundisporus, which also has a blue, viscid pileus, but the stipe lacks an annulus.

Cortinarius perfoetens growing under Nothofagus cunninghamii.
Photo: Eileen Laidlaw, used with permission, all rights reserved.
Also in the batch was an unidentified species of Cortinarius. The photo showed the distinctive shaggy stipe and glutinous pileus of Cortinarius perfoetens. Like C. metallicus, this species was formerly placed in Rozites (as Rozites foetens) due to the presence of a distinct annulus on the stipe. The associated habitat information indicated 'Sub Alpine grove of Myrtle Beech and Tea tree, nearest tree Myrtle Beech', which is also in accord with the strong association between Cortinarius perfoetens and Myrtle Beech. Almost all records of the fungus are with this tree - with the exception of a well-documented collection by John Walter from the Wombat State Forest, under Eucalyptus and a long way from the nearest Myrtle Beech stands in the Otway Ranges and the Central Highlands of Victoria.

Arrhenia chlorocyanea.
Photo: Eileen Laidlaw, used with permission, all rights reserved.
Another of the attached photos stood out due to the small, rather dark greenish-blue pileus in combination with decurrent lamellae. This had been correctly identified by Eileen as Arrhenia chlorocyanea, a very uncommon species. Another of the unidentified fungi matched a rather large white Lactarius that is similar to the Northern Hemisphere L. piperatus, but will not be the same species, and so for the moment we are refering to it by the tag name Lactarius sp "austral piperatus". A multicoloured Russula with a red pileus and yellow lamellae and stipe matched an illustration in Gates & Ratkowsky A Field Guide to Tasmanian Fungi (p. 143) - we are denoting this species Russula sp. "red-yellow". Further fungi reported from the vicinity of Mt St Gwinear included Leotia lubrica and various other species of Russula.

For a few minutes we were transported to the gloomy depths of a rainforest in a 'virtual' foray as we flicked through the images. I thank Eileen for the chance to accompany her 'real' foray

Data from records such as these are entered in the Fungimap Records Database. Records eventually find their way to the Atlas of Living Australia, as dots on maps. You can submit records to Fungimap (info@fungimap.org.au) using the records spreadsheet.

Tom May
Fungimap / Royal Botanic Gardens Victoria