• Proposed
  • Under Assessment
  • Preliminary Assessed
  • Assessed
  • VUPublished

Tulostoma niveum Kers

Search for another species...

Scientific name
Tulostoma niveum
Author
Kers
Common names
vit stjälkröksvamp
hvit styltesopp
white stalkball
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Agaricaceae
Assessment status
Published
Assessment date
2019-03-25
IUCN Red List Category
VU
IUCN Red List Criteria
B2ab(ii,iii,iv,v); C2a(i)
Assessors
Ainsworth, A.M. & Jeppson, M.
Reviewers
Dahlberg, A., von Bonsdorff, T., Gonçalves, S.C. & Kałucka, I.L.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/58521336/58521340

Justification

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. It is known from less 75 localities in Finland, Sweden, Norway, UK and Switzerland with the main population in Sweden. The total number of localities, including unknown, is estimated not to exceed 150. The number of mature individuals per site it is estimated to be typically around 50 and rarely approach 100, hence the total population is estimated not exceed 10000.

The area of occupancy of this species is also restricted, and would be very unlikely to exceed 2000 km2 even taking into account unknown localities. The population is severely fragmented, as it is comprised of very small isolated subpopulations.

Tulostoma niveum mainly occurs in stable and not threatened habitats. However, the total population is estimated to slowly decline as a consequence of habitat overgrowth and exploitation. It is sensitive to trampling. It is 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 Vulnerable B2ab(ii,iii,iv,v); C2a(i) based on its restricted area of occupancy, severe fragmentation, small population and decline.

Geographic range

Tulostoma niveum is endemic to Europe occurring in Finland, Norway, Sweden, Switzerland and the United Kingdom. The species has been actively searched for by different initiatives during the last decade in Norway, Sweden and Scotland. A recent finding in Krasnodar (southern Russia) needs confirmation (currently identified from photo).

Population and Trends

The overwhelming majority of the known world population is 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). It is 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 average number of mature individuals per location is estimated to be 50 (rarely up to 100), hence the total population not to exceed 7500 (or possibly 10000).

The species was the subject for a Species Action Program in Sweden 2005-2010 with a focus on inventories of known sites, to search for new sites and check the status of these sites. It was found to mainly grow 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


Habitat and Ecology

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 the UK are located in open, unshaded areas, not under trees.

Threats

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 is mainly growing in stable not threatened habitats. 

However, as ceased grazing may lead to increased shading, the population of Tulostoma niveum in Sweden is assumed to be decreasing slightly. The species is sensitive to trampling wear along paths and trails on the moss-covered limestone outcrops. In Finland, Rosa rugosa is a big threat for the coastal Finnish locality.

Conservation Actions

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. A recommended conservation action where invasion by Betula is a threat would be cutting and stump treatment of these trees.

Population genetics studies on the physical extent of genets (and how many ramets per genet) would improve estimates of “mature individuals”.

Use and Trade

The species is not used.

Source and Citation

Ainsworth, A.M. & Jeppson, M. 2019. Tulostoma niveum. The IUCN Red List of Threatened Species 2019: e.T58521336A58521340. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T58521336A58521340.en .Downloaded on 31 January 2021

Country occurrence