FUNGI (Chapter 10)

Lead Authors:  Anders Dahlberg and Helga Bültmann 

Contributing Authors: Cathy L. Cripps, Guðríður Gyða Eyjólfsdóttir, Gro Gulden, Hörður Kristinsson and Mikhail Zhurbenko

SUMMARY

Fungi are one of the most species-rich groups of organisms in the Arctic. While the occurrence, distribution and ecology for lichenized fungi (lichens) are reasonably well known, less is known about non-lichenized fungi (normally just called fungi), including lichenicolous fungi (fungi living on lichens) and in particular, microfungi. The known number of fungal species in the Arctic is presently about 4,350, of which 2,600 are macrofungi and 1,750 are lichens, the rest are microfungi. The fungi have largely a cryptic life form and have therefore not been exhaustively inventoried. Hence, total fungal-species richness in the Arctic may exceed 13,000. Local species richness is typically high and can be very high, e.g. about 50 lichen species on less than 1 m². Most species appear to be present throughout the Arctic, and they also occur in alpine habitats outside the Arctic, particularly in the northern hemisphere. Few fungi are endemic to the Arctic. Of the lichens, 143 species are listed as Arctic endemics, but it is likely that the major part will prove to be synonyms of other species.

Fungi are pivotal in Arctic terrestrial food-webs. Mycorrhizal, saprotrophic and pathogenic fungi drive nutrient and energy cycling, and lichens are important for primary production. Reindeer lichens Cladonia subgenus Cladina spp. form dominant vegetation types in many areas and function as keystone species.

As for other inconspicuous organism groups, it is obviously desirable to gain a better knowledge of the identity, occurrence and functions of fungal species, and particularly the large number of unrecorded species (mainly microfungi). An evaluation of the conservation status of Arctic fungi is feasible, and the mapping of rare and endemic species is necessary. Enhanced monitoring and functional research would enable more accurate prediction of how fungal diversity and the ecosystem functions of fungi will develop with climate change.

Effects of climate change on diversity of Arctic fungi are predicted to be gradual but radical over time, due to changes in vascular plant flora and vegetation, especially the expansion of shrubs. Most fungal species associate with living or dead parts of specific vascular plants and will respond directly to changing composition, abundance and location of the vegetation. Similarly, terricolous lichen communities will be affected by increased competition from vascular plants. The changing vegetation will transform the fungal diversity and thereby affect ecosystem services provided by fungi, such as plant’s uptake of nutrients, decomposition and long-term carbon sequestration in soil, although unknown how and to what degree. The conservation status of Arctic fungi is predicted to scarcely be affected within the next decades but greatly changed over the long term.

I want to tell you something I learned about plants from the late Kakkik that I tried myself. My sister’s late husband used to know about nirnait, caribou lichen, the plants that caribou eat. They are long and you pull them out. They tend to grow in swampy areas. I boiled them when all the people in our camp were sick. I was the only one up and about when we were living in a fishing camp. My mother had been admitted to the hospital and we were waiting for her return in August. Six of my family members were sick in bed. I boiled some caribou lichen in a pot for a long time, following my brother in-law’s advice. He told me to stop boiling them when the water turned black. I waited for them to cool down and I gave each sick person some to drink. The next day, they were all up and about. It looked like the cough syrup in a bottle. Aalasi Joamie in Joamie et al. 2001.

INTRODUCTION

Fungi are an extraordinary group of organisms. They constitute a large portion of Arctic biodiversity and are essential in the functioning of Arctic terrestrial ecosystems. A substantial part of the fungi is lichenized and generally termed lichens. The remaining part of the fungi is in general terms just called fungi and will here be referred to as fungi. Given favorable weather conditions, some may produce short-lived, sometimes prominent, sporocarps (mushrooms), but predominantly, and for many species exclusively, they exist as cryptic and hidden mycelia in e.g. soil and in living or dead insect or plant tissues. The most well-known group of fungi in the Arctic is the lichenized fungi (lichens) because they grow on substrate surfaces and often contribute conspicuously, and colorfully, to Arctic vegetation. This is particularly apparent in the high Arctic and in reindeer lichen-dominated vegetation types in the sub-Arctic.

Here we review the knowledge and status of Arctic macroscopic fungi, i.e. visible sporocarps of fungi, and lichens. Microfungi constitute the most species-rich fungal group in the Arctic, but are only briefly mentioned due to scarcity of knowledge.

CONCLUSIONS AND RECOMMENDATIONS

Fungi is a key group of organisms with high species richness and large significance for ecosystem processes in the Arctic. Except for macrolichens, however, their presence and significance has often been overlooked and poorly appreciated in the Arctic, despite being species rich, abundant and pivotal in carbon and nutrient cycling. Distributional and ecological knowledge is reasonably good for macrolichens but sparser for fungi and microlichens.

Even with these caveats, present knowledge largely enables us to predict the future of Arctic fungi. The unavoidable greening of the Arctic will steadily and significantly affect the distribution and abundance of fungi, as habitat conditions gradually transform the distribution and abundance of plants. This change is in progress already, but studies of Arctic soil fungal communities imply that the response as yet is relatively slow (Timling & Taylor 2012). Therefore, we judge that these changes will only rarely affect their conservation status in the immediate future. However, over time the effects of climate change and subsequently transformed vegetation will have profound effects on the distribution and composition of fungi and consequently also their ecosystem functions. Most of the species are circumpolar and also distributed outside the Arctic. However, a large proportion of them are confined to Arctic-alpine habitats of which the greater part is located within the Arctic and few are true Arctic endemics.

The following actions would enable a more thorough analysis of the status and trends of Arctic fungi.

• Long-term funding is necessary to maintain and train Arctic specialists in mycology and lichenology and to ensure research and monitoring to take place.
• The identity and taxonomy of species with unclear status (e.g. poorly known fungi and potentially endemic lichens) should be critically examined. The large potential of fungal analysis of deep sequenced environmental samples will largely benefit by clarified fungal taxonomy.
• A checklist for Arctic fungi should be compiled.
• The knowledge of distribution and ecology for all fungi, but in particularly for non-lichenized fungi, should be improved.
• Conservation status should be assessed for Arctic lichens and fungi, preferentially at both the Arctic and global scales.
• Long-term monitoring within representative Arctic habitats would enable us to document and follow fungal species shifts over time.
• Analyses of how vegetation changes may, based on knowledge of fungal ecology, predict potential habitats for fungi in space and time.
• Efforts to analyze the effects of slowly shifting fungal communities on ecosystem processes such as nutrient cycling and carbon fluxes are needed.
• Analyses of how the supply of reindeer food lichen communities will alter due to vegetation change should be conducted in order to better predict future conditions for populations of reindeer/caribou.