Should it be assessed as NT or VU (less than 10 000 mature individuals or less than 15 (20 000 mature individuals)? Sweden assessed it as NT 2015.
Tulostoma niveum, the white stalkball, is a rare endemic fungus in Northern Europe (with an outlying population in Switzerland) that occurs among bryophytes on calcareous rocks and boulders. Known from less 75 localities in Finland, Sweden, Norway, UK and Switzerland with the main population in Sweden. The total number of locations, including unknown, is estimated not to exceed 150. The on average number of mature individuals per location is estimated to be 50 (100), hence the total population not to exceed 7500 (or-15000).
Tulostoma niveum mainly occurring in stable and not threatened habitats However, the total population is estimated to slowly decline as a consequence of habitat over growth and exploitation. Sensitive for trampling. Assessed as nationally declining in Finland, Norway and Sweden. Designated as Vulnerable in the unofficial Red Data List of UK and treated as vulnerable and requiring conservation action in the Scottish Biodiversity.
It is assessed as Near Threatened (or Vulnerable) based on small population and decline.
Endemic to Europe occurring in Finland, Norway, Sweden, Switzerland and UK. The species has been actively searched for by different initiatives during the last decade in Norway, Sweden and Scotland.
The overwhelming majority of the known world population are located in Sweden. The total number of known localities is less than 65 (Finland 2, Sweden estimated to be 50 (2015), Norway 4 (2015), UK 4 (restricted to Scotland). A single Swiss site is reported in Jeppson et al. (2017). It is assessed as threatened or near threatened in all northern countries; Finland (2010, CR, B1ab(iii)+2ab(iii); D1), Norway (2015, EN, B2a((i),ii)b(iii)c(iv); C2a(i)b), Sweden (2015, NT, (C2a(i)) and UK it was was designated as Vulnerable )(D2) in the unofficial Red Data List (Evans et al 2006). Currently treated as vulnerable and requiring conservation action in the Scottish Biodiversity List. The total number of locations is estimated not to exceed 150. Each discrete fruiting patch is interpreted as a mature individual. The on average number of mature individuals per location is estimated to be 50 (100), hence the total population not to exceed 7500 (or-15000).
The species was the subject for a Species Action Program in Sweden 2005-2010 with a focus on inventories on known sites, to search for new sites and check the status of these sites. It was found to mainly growing in stable environments which are not endangered. However, the total Swedish population is assessed as slowly decreasing due to overgrowth in forests due to a decline in forest grazing, exploitation and possibly also trampling by man in some areas where walking tracks cross calcareous rocks.
Population Trend: Decreasing
The white stalkball is a saprotrophic fungus growing in moss cushions (mainly Tortella tortuosa and Ditrichum flexicaule) on limestone boulders or walls with no mineral soil beneath the associated moss. In Sweden, most of the records originate from forested areas where it occurs in glades and along forest edges where there is sufficient light. Although there are some inland records, a majority of the findings have been made at sites situated close to the seashore. The sites in UK are located in open, unshaded areas,not under trees.
In Scotland, the major threat is cessation of grazing leading to colonisation and shading of site by Betula saplings. The overwhelming majority of the known world population is currently in Sweden where it mainly is growing in stable not endangered habitats. The total population of the country is, however overall decrease slightly, due increasing shading of sites as a consequence of ceased grazing and exploitation through construction. The species is also sensitive to trampling wear along paths and trails on the moss -covered limestone outcrops. In Finland, Rosa rugosa is one big threat for the coastal Finnish locality.
Exploitation of habitats where white stalkball grows is a disadvantage given its extremely limited geographical extent. Trampling by man is a potential threat in some areas where walking tracks cross calcareous rocks. Cutting and stump treatment of invasive Betula.
Population genetical investigation of physical extent of genets (and how many ramets per genet) would improve estimates of “mature individuals”
Fleming, L.V., Ing, B. & Scouller, C.E.K. 1998. Current status and phenology of fruiting in Scotland of the endangered fungus Tulostoma niveum. Mycologist 12(3): 126-131.
Holden, E.M. (2011). Baseline data to indicate the extent of the white stalkball (Tulostoma niveum) on Craig Leek Site of Special Scientific Interest. Scottish Natural
Heritage Commissioned Report No. 177
Jeppson M. 2005. Åtgärdsprogram för bevarande av vit stjälkröksvamp (Tulostoma niveum). (Species Action Program for Tulostoma niveum, In Swedish with English summary). Naturvårdsverket, report 5512. Can be downloaded through internet.
Jeppson, M. 2006. Tulostoma niveum - en av världens sällsyntaste svampar [Tulostoma niveum - one of the rarest fungi in the world]. Svensk Mykologisk Tidskrift 27(2): 58-63.
Jeppson, M. 2006. Riksinventering av vit stjälkröksvamp (Tulostoma niveum) 2004-2006, Länsstyrelsen i Örebro län, publ. nr. 2007-42
Jeppson M., Altés, A., Moreno, G., Nilsson, R.H., Loarce, Y., de Bustos, A. & Larsson, E. (2017). Unexpected high species diversity among European stalked puffballs - a contribution to the phylogeny and taxonomy of the genus Tulostoma (Agaricales). Mycokeys 21: 33-88.
Jordal J.B. & Johnsen J.I. (2009) Hvit styltesopp Tulostoma niveum - nå også på Sørvestlandet. Agarica 28: 64-70 [http://www.jbjordal.no/publikasjoner/Tulostoma_niveumAgarica-28.pdf].
Kers, L.E. 1978. Tulostoma niveum sp. nov. (Gasteromycetes), described from Sweden. Botaniska Notiser 131: 411-417.
Lost & Found Fungi Project (2018) website: http://fungi.myspecies.info/content/lost-found-fungi-project (accessed 22 Feb 2018)