The North American Mycoflora project – the first steps on a long journey

Authors


(tel: +1 510 642 7987; email pogon@berkeley.edu)

North American Mycoflora Project, in New Haven, Connecticut, USA, July 2012

Where would plant ecology and evolution be without the basic knowledge of plant species and distributions? Fortunately we do not need to answer this question because floristics is a mature field, and published floras deliver essential tools for plant ecologists who need to identify species or use plant distribution data for conservation and biogeographic work. By contrast, fungal biologists seldom have the equivalent knowledge, as there are relatively few published mycofloras (fungas, mycobiotas or mycotas). The mycofloras that do exist are necessarily limited to macrofungi, essentially mushrooms, but even with this delimitation the task of assembling a mycoflora is daunting. This is because the number of species is large (Mueller et al., 2007), the fruiting structures are ephemeral and often inconspicuous, the basic taxonomic work is still woefully incomplete, and there are few people trained to do the work. As a result within the entire continent of North America there is not a single regional, state, or local catalogue of the macrofungal species that presents a credible account of the species present and their distributions. The contrast to Europe is striking. The Netherlands, Germany and Switzerland all have surveyed mushrooms and produced extremely useful keys and distribution maps (Krieglsteiner, 1991; Anonymous, 2012a,b), and the Funga Nordica (Knudsen & Vesterholt, 2012) provides an excellent model for a modern mycoflora for Northern Europe.

This is not just a problem for fungal biologists or for North America. In fact the problem is most acute for plant scientists that need to identify the mycorrhizal or pathogenic fungal associates of their plants, and for fungal ecologists that need a global view of diversity. Without a mycoflora identification is an impossible task for the nonspecialist, and without an accurate catalogue of species and their ranges no global patterns can be assembled. Thus the real advantage in a mycoflora is that it makes fungi accessible to nonspecialists. To rectify this problem, the first meeting for the North American Mycoflora project just took place in New Haven, Connecticut in July. The meeting was the culmination of the Fungal Environmental Sampling and Informatics Network, an National Science Foundation (NSF) funded research coordination network that New Phytologist readers may be familiar with from early meetings (Bruns et al., 2008).

A long way to go, so why now?

It was very clear from the meeting that there is substantial unfinished work on the North American Mycoflora and that the barriers to doing the work are huge. The good news is that there are three developments that now make the project tractable: new web tools, involvement of the public, and DNA sequence analyses. The meeting was structured to highlight and coordinate these three elements. It was agreed at the beginning of the meeting that the North American Mycoflora would be a strictly electronic resource. The advantages to a web-only approach are that species descriptions could be directly linked to specimen data, images, sequences, and distributions maps. Keys and descriptions could also be readily updated and corrected, and the mycoflora could be universally available via smart phones or tablet computers. Brach & Boufford (2011) made these same points for plant floras; the message is clear – it is time to go electronic.

‘…the number of trained fungal taxonomists to make such collections is small and decreasing. For this reason the involvement and training of “citizen scientists” is an absolute necessity.’

The electronic way forward

The exact way for the mycoflora to go electronic was not clear because there are many options. However, several platforms looked very promising and are likely to be incorporated. The image-rich, random-access keys that are used at the Discoverlife.org website are likely to be a ‘key’ component. John Pickering (University of Georgia, Athens, GA, USA), the creator of that website gave a live demonstration that illustrated the power of these keys to rapidly delimit possible identifications. Thus far the fungal component of Discoverlife.org is small, but this will likely change shortly as a result of the meeting.

Assembling the existing collection data is another essential step toward the mycoflora, and the recently funded Advanced Digitalization of Biological Collections (ADBC) grant for the Macrofungal Collections Consortium is a great start. Barbara Thiers (New York Botanical Garden, USA), who spearheaded the grant, presented the details of the project at the meeting. The goal is to digitalize the data for 1.3 million collection records of macrofungi housed in 35 institutions in the United States. MycoPortal (www.mycoportal.org), the web tool that is being developed with the ADBC project, will help people access, organize and link the data. Scott Redhead's (Agriculture Canada, Ottawa, Canada) presentation presented parallel efforts that are ongoing in Canada, and these could be coordinated with MycoPortal. Mexico remains the main missing piece of North America, and unfortunately will likely remain so for the foreseeable future.

A crucial role for trained members of the general public

Modern collections are equally important, as they have the advantage of often being coupled with high quality images, and DNA is more easily extracted from them. Unfortunately the number of trained fungal taxonomists to make such collections is small and decreasing. For this reason the involvement and training of ‘citizen scientists’ is an absolute necessity. These are people who are employed in other occupations but dedicate much of their time to fungal taxonomy. The term ‘amateur’ does not do them justice, as they are often highly accomplished within the field of fungal taxonomy. They were represented among the 70 attendees at the meeting by 14 handpicked, exceptional individuals. Nathan Wilson (Marine Biology Lab, Wood's Hole, MA, USA), author of Mushroom Observer website, Rod Tulloss (research associate at the New York Botanical Garden and retired Fellow of Bell Laboratories, USA), extra-academic expert on Amanita, and Mike Wood (computer consultant, San Leandro, CA, USA), author of Mykoweb, are good examples. Bart Buyck (Muséum national d'Histoire naturelle, Paris, France), pointed out that taxonomy of the genus Russula in Europe has been driven by citizen scientists and coordinated by meetings of self-trained specialists for decades. North America lacks this level of coordination, but clearly needs to develop it.

Why specimens and sequences are needed?

The involvement of the public in ongoing mushroom surveys is similar in many ways to bird counts in North America (http://birds.audubon.org/christmas-bird-count), urban plant surveys in France (http://sauvagesdemarue.mnhn.fr/sauvages-de-ma-rue/presentation), moth surveys in the UK (http://www.mothscount.org/), or a growing number of other citizen science projects (http://www.citizensciencealliance.org/). In all cases large numbers of individuals are required to cover the area and training is needed to ensure quality data. One main difference, however, is that sighting alone is sufficient for birds, urban plants, or moths, but not for fungi. Specimens are an absolute requirement for fungal surveys, and there was universal agreement on this point at the meeting. Without a specimen subtle differences among fungal species would be missed and the lumping of species would mask continental distribution patterns and underestimate species richness.

The need for DNA sequence analysis in fungal surveys is a second major difference from other public surveys. Sequences are critical because morphologically defined species are often collections of unrecognized, undescribed, cryptic species (Geml et al., 2006; Carriconde et al., 2008; Grubisha et al., 2012). This point was strongly reinforced by Else Vellinga (University of California, Berkeley, CA, USA), who showed that the most frequently collected fungi are often mis-identified or represent composites of several species. Most of these mis-identifications are due to the widespread application of European names to North American fungi. This is certainly a worldwide problem as European names are the most numerous and most widely applied, but it is particularly acute in North America where so much mycorrhizal work is dependent on fungal taxonomy. This problem may seem like a taxonomic issue that would only concern specialists, but it has much broader impacts because it directly affects the way we think about dispersal, biogeography, conservation, and invasive species. When many species are lumped into one it is not surprising that dispersal appears unlimited, or that biological invasions go unnoticed for decades (Pringle et al., 2009). In addition sequences based on well-identified voucher collections help solve one of the biggest problems in that field, the inadequacy of public fungal databases (Bidartondo et al., 2008). The voucher and sequence requirement for the mycoflora are now enshrined in the motto (Fig. 1).

Figure 1.

The logo and motto for the North American Mycoflora Project.

How does one sample a continent and assemble the results?

What is the most efficient way to sample a continent, preserve all the specimens, and sequence enough of them to capture the pattern? The ‘mycoblitz’ model where large numbers of people from the general public are recruited for seasonal forays, and a smaller subset of trained individuals identify, photograph, preserve, and curate the specimens has been applied in several parts of the United States and Canada, and was discussed by Patrick Leacock (Field Museum of Natural History, Chicago, IL, USA), Else Vellinga (University of California, Berkeley, CA, USA) and Scott Redhead (Agriculture Canada, Ottawa, Canada). The primary drawback to this approach is that the volume of collections overwhelms the resources of the limited number of experts. Furthermore, collections that cannot be identified quickly are often not saved, so more difficult or obscure taxa are underrepresented. Vellinga also presented a small-group collecting model where a subset of the citizen scientists are provided with web coordination, sequence access, and permits. This approach decentralizes the identification and processing and is better in areas with unpredictable climates.

Assembling the results is an equal or greater problem. The example of the recently revised Funga Nordica (Knudsen & Vesterholt, 2012) was presented by Henning Knudsen (Natural History Museum of Denmark, Copenhagen, Denmark), and he provided an excellent model for the North American effort. However, North American is much harder because modern monographic treatments are not available for most fungal groups and large numbers of species remain undescribed. For example, Bart Buyck (Muséum national d'Histoire naturelle, Paris, France) pointed out that there are only > 400 names for Russula species in North America, but there are estimated to be between 1000 and 2000 species of Russula on the continent. This is a particularly depressing example, but most other large genera are similarly unstudied in North America.

We are clearly a long way from a continental mycoflora, but this meeting was the first step in the right direction and may help spur similar projects elsewhere. Maintaining momentum toward the goal and finding funding for it are now the most pressing issues. For those who missed the meeting, videos of the presentations, and links to more information (www.northamericanmycoflora.org/) may help to expand the interest and facilitate the movement toward these goals. Let's do it!

Ancillary

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