Acta Bot. Need. 37(2), June 1988, p. 251-263 Macromycetes in alpine snow-bed communities — mycocoenological investigations B. Senn-Irlet Systematisch-Geobotanisches Institut der Universitdt Bern, Altenbergrain31, CH-3013 Bern, Switzerland SUMMARY For a period of 3 or 5 years, six plots in the alpine zone of Switzerland, mainly in the Bernese Oberland, have been observed for macromycetes. In snow-bed communities, 88 species could be found, 25 on siliceous ground and 63 on calcareous ground. Fungi with a wide ecological and distribution dominate in range a large area acidic snow-bed communities(Salicetum herbaceae(SAH)) and fungi with distinctly specified ecological claims dominatein calciphilous snow-bed communities(Salicetum retuso-reticulate (SAR)). In both vegetation types mycorrhizae-formers play a most important role. The differences in the between for flora the two snow-bedcommunities are greater the macromycetes than for the phanerogams. Both vegetation types are characterized by macromycetes. Key-words: agaricales, alpine zone, discomycetes, mycocoenology, snow-bed communities. INTRODUCTION Snow-bed vegetation often passes for a paragon of a high alpine vegetation type, yet this vegetation type takes up only a small surface of the entire alpine plant cover. In fact, grass heaths dominate the alpine zone of the central European Alps. Snow-bed in communities occur habitats with extreme ecological conditions, normally at the bottom of northern with thick a exposed slope a snow cover during winter, or at higher altitude in with The short regions relatively high precipitation. very vegetation period, the main feature of snow-bed lasts 3 months in favourable and communities, years 8 weeks in unfavourable ones (Walter & Breckle 1986). Among the very few plants found that can develop under these rough climatic conditions are the dwarf willows. The rest of the species are tiny, nestled to the soil. Liverworts and mosses play an important role in such vegetation types. Macromycetes are a very substantial part of these alpine communities. It was Favre (1955) who first focused attention on the mycoflora of such extreme habitats. More- he discovered of of over, a high diversity mycorrhizae-forming fungi dwarf shrubs. The aim of this investigation was to assess snow-bed communities of siliceous and and of limestone areas both quantitatively qualitatively. This paper is part a more com- prehensive study on the ecology, sociology and taxonomy of alpine macromycetes (Senn-Irlet 1986). 251 252 B. SENN-IRLET Fig. 1. Map of Switzerland showing the investigation areas. MATERIALS AND METHODS The investigations were carried out in four areas of the alpine mountains of Switzerland 2 (Fig. 1). At each site, plots ofat least 30 m were selected in vegetations consideredto be of described with releves and homogeneous composition. Vegetation was Braun-Blanquet symbols. Mosses and lichens were collected and identifiedin the laboratory. Mycocoenological analyses In accordance with the proposals ofBarkman (1976) and Arnolds (1982), permanentplots of 2 established and observed for of 3 30-100 m were a period (four plots) or 5 years (two and information about plots) to achieve detailed qualitative quantitative macromycete and removed from abundance, frequency and biomass. The carpophores were counted the plot then dry weight was measured by weighing some mature carpophores. The calculated: following parameters were (1) Density (£>) ofcarpophores per year: z:c x 100 DC = y , s where x = number of visits, C=number of carpophores, s = surface of the plot, y = number ofobservation years. Total numberof (2) carpophores per plot: tDC = Y.DC r (3) Average density (aD) of carpophores per year; tDC aDC = • y ALPINE SNOW-BED MACROMYCETES 253 (4) Maximum density (mD) of carpophores per visit: cwlOO — mDCv(iy) ——, 5 where = number cm maximum of carpophores established on one visit during the observation period. RESULTS Vegetation Snow-bed vegetation on limestonediffersstrikingly from that on siliceous ground. Based on the composition ofthe phanerogams, all releves can be ascribed to already well-known plant communities (Braun-Blanquet 1949). Yet, plot 33 shows an interesting species The unusual of composition. occurrence Arabis coerulea and Salix reticulata in plot 33, in with is caused an area predominantly acidophilous flora, by glacially transported dolomiticmaterial in moraine. the is still a However, community interpreted as a SAH. The three plots of SAR show several species typical of dwarf shrubs and of calcareous heaths. These vegetation types can be foundin the neighbourhood, thus they formcontact communities.Above plot 41 the Rhododendro-Vaccinietum,another type of dwarf shrub heath, is present. Adjacent to plots 42 and 43 Caricetum ferrugineae has developed a heath moist grass community. These neighbouring vegetation types influencethe floristic composition of the SAR plots. in Mosses play an important role the structure of snow-beds. In SAH there are nearly beside whereas exclusively acrocarpeous mosses some tiny hepatics, in SAR pleuro- dominate. the richness of lichens is in carpeous mosses Moreover, striking SAR. In relation to their cryptogam composition the two snow-bed communities differ greatly; there are only a few species in common. For the mycological study it is interesting that only five species ofhigher plants may form ectomycorrhizas, i.e. Salix herbacea, S. retusa, S. reticulata, Dryas octopetala and Polygonum viviparum. Mycoflora Two examples of the original mycocoenological data are shown in Tables 1 and 2. The differences between these siliceous the great two plots, one on ground other on calcareous ground, are significant. The plot in the SAH is very poor in fungal species; however, some compensateby their abundance. Many of the SAH macrofungi have a wide ecological range, a large distri- bution area, and are found in a wide altitudinalrange. The mycoflora is considered to be rather trivial. Psilocybe chionophila, a species close to P. montana, and Galerina chionophila are exceptions. They are known only from arctic-alpine snow-beds. The of in is minimal: 2 productivity macrofungi plot 11 1 g dried substance per 100 m l An often of small bodies late in the year~ . singular production fruiting very season, due to harsh climatic conditions, explains the typical low macrofungi productivity of SAH communities. Indeed, carpophores with a cap size between 0-5 cm and 2 cm are standard, rarely some medium-sized carpophores (e.g. Cortinariusfavrei) occur. The plot in SA R reveals quite a differentpicture. Overall 37 species have been foundin 5 years. Apart from some fungi with a wider ecological range, several species have to be con- sidered found as endemic exclusively in the alpine zone ofCentralEurope and Scandinavia. bound Obviously they are to special plant species. For instance, Marasmius epidryas only dead of Other occurs on lignified parts Dryas octopetala (Rosaceae). fungi as Inocybe 254 B. SENN-IRLET mgmg 6060 (3y) 2944 804 1298 258 524 d.w. 6 mDC 84 53 31 59 97 tDC 134134 6-26-2 106 311313197 2 35 1 32 aDC 2-6 116 4545 35 ) 3 3 2 9494 — 53 — 38 2 1985 m (100 1984 0 0 — — — — — 50 5 6 3 DC 6 53 59 1983 253253 131 3 9/9 3030 1 — 17 — 12 1985 22/8 00 — — — — — 25/7 00 — — — — — 20/8 00 — — — — — 1984 3/8 00 — — — — — 4 1400006666 27 2 17 — 19 23/9 . herbaceae 2 m 1 24/8 1515 1515 1 32 1983 1983 — — exp.; Salicetum 11/8 0 0 — N 0 0 — — ——— — — 27/7 m.ii.M., 3 6 1 3 2 —— —— — + community 17/9 1982 — — — 2315 21/7 0 0 02030029 6 3 — + snow-bed 16/9 1981 Zinggenstock, 4/8 0 0 — — — — — acidic of an slope of mycocoenosis cinnamomeoluteacirmamomeolutea Grimsel-Oberaar, species carpophores chionophilachionophila vittaeformisvitlaeformis tetraspora conferendum The II: 1. no. no. no. Table Total Total Psilocybe Galerina Laccaria Entoloma Dermocybe Plot ALPINE SNOW-BED MACROMYCETES 255 egenula, I. luteipes and Cortinarius favrei form mycorrhizae with dwarf willows (Salix other seel. Glaciales), Dryas octopetala and presumably with some alpine phanerogams. also be bound substrates. Debaud showed that Saprophytic fungi may to special (1983) litter extracts of Dryas octopetala stimulated the growth of several calciphilous Clitocybe species while an extract of Salix herbacea had the opposite elfect at least on Clitocybe lateritia. the of SAR have found that in Among remaining species we many are very rare such Arrhenia Galerina and albidum. In Europe, as acerosa, pseudocerina Gerronema plot 42 Marasmiusandrosaceus must be regarded as an alien species; it grows on the needles of Picea abies that have been blown by wind into the plot. In fact the presence ofMarasmius androsaceus indicatesthe proximity of subalpine spruce forest. “ 1 The productivity of fungal biomass in SAR is 10 so it is 10 times higher thanin g year , SAH. Beside many tiny fruiting bodies some single big carpophores occur, such as Russula delica which reached normal size. the lower altitude the (plot 42), cap Due to vegetation of the SAR lasts than that in the SAH This be period investigated plots longer plots. may the main for such differences in the the the reason great productivity. In SAH plots snow melts only during July; in 1981 and 1984 there was thick snow cover even in the first week ofAugust, whilethe SAR plots were free ofsnow from mid-July. In SAH the fructification period starts in the second half of August (Table 1) and is often interrupted by snowfalls in September. Only in years with exceptionally high September temperatures can the mycoflora of SAH develop fully. This was the case in autumn 1985.On 30 September 1985 plot 33 had eight species, with a totalof 33 fruiting bodies; thisis the best record ofall visits to a SAH plot. with a wide and distribution dominate in Fungi ecological range a large area SAH, while fungi with specified ecological demands dominate in SAR. This is true not only in the case of plot 11 versus 42 but also when comparing all plots (Table 3).