Should be namned Aurantiporus croeus
Well known, much searched for and a conspicuous wood-inhabiting fungus confined to coarse old veteran oaks in wooded meadows and pastures. Hapalopilus croceus is nationally red-listed in 11 European countries. It is considered to have its main present distribution in Sweden (listed CR), Poland (listed EN), Russia (not evaluated), Germany (CR) Estonia (CR) and Latvia (EN). It is very rare and its habitat, coarse old oaks is declining throughout Europe. Furthermore, there is a serious gap in the age-structure of oaks, a few old coarse veteran oaks (>400 yrs), far too few mature oaks (200-400 years) and many young oaks (< than 100yrs ).Long lived mycelia, probably typically more than 100 years. Appears to be present in Asia and America. The status there, presently not known, hence global evaluation uncertain.
Preliminary global red-list assessment: DD (Data Deficient) due to unknown status in Asia and North America. Can hopefully soon be cleared and a more comprehensive global assessment made.Red-List evaluation for Europe turns out to be CR (Critically Endangered).
A globally (and in Europe) widely spread species and not qualifying for criteria B and D. Difficult to estimate the population size, although in Europe it is known from about 100 localities (the highest no in Sweden, Latvia and Germany), with typically single to few occurrences (mycelia) per site. Possibly could the C-criteria be used. However, in the lack of estimation of population size, only criteria A can be used and population development inferred from habitat development. The evaluation period is estimated to be 100 years (=3 generations which in this long lived species is considered to be more than 33 years).
More information needed about: the occurrence and status of H. croceus in Asia and North America. References for decline of coarse oaks in Europe. Status in Russia.
This is a species, which largely follows the distibution of oak (Quercus) in Europe. The species is found from the Mediterranean Sea to the northern boundary of oak in northern Europe. It is also found in North American temperate deciduous forest, probably in East Asia.H. croceus is known from at t least 24 European countries, but everywhere scattered and rare, with the largest populations in Sweden and Latvia (each with about 1/3 of Europe’s known localities). In France 5 localities, 2 before 1920 (PAM). One tree in Denmark.
Because oak trees has been intensively utilized for hundreds of years in Europe, H. croceus has been in long-term decline, and the orange polypore is today one of Europe’s rarest and most endangered species of fungi, limited to areas that still have concentrations of veteran oaks. Oak forests in most of Europe have been severely exploited through the centuries, in particular since 1800, especially trees with rough dimensions. Old and rough oak trees are therefore rare or absent altogether over large areas, and is limited to small and scattered populations and individual trees.Today the felling of such trees has largely ceased. However, most places lacking an intermediate generation of oaks, which creates a discontinuity and thus an ecological “bottleneck”. Decline of veteran oaks has happened in both forests and in the agricultural landscape including parks and cemeteries.
How is the situation outside Europe?
Population Trend: Deteriorating
The orange polypore is a magnificent, saffron-orange-red, wood-inhabiting fungus that grows on old and rough veteran oak trees, in forests and farmland. H. croceus is confined to oald oaks and are found in deciduous forest , mixed forest , parks and pastures. It is a weak parasite and saprotroph on old and rough oversized, living and dead oak trees (veteran trees), both standing and lying down. In South Africa it is reported from chestnut ( Castanea ). Most observations in Europe is done on living, old, giant and hollow oaks, where the annual fruitbodies appear on dead parts of the tree, most of the lower part of the trunk, the tree’s base or cavity. Rarely found on fallen trunks. The fungus colonize living trees through holes, cavities etc , growing so parasitic in the dead heartwood, and continuing degradation after the tree has died and fell over. Each oak holds probably only one mycelium, genetic individual. Fruit bodies are annual, but the mycelial individuals can be very long lived, many decades and potentially until the wood is rotted out, which of oak may take several hundred years. At the only locality in Denmark,what is considered to be the same individual mycelia (genotyper) has been fruiting for more than 70 years.
The species is threatened by a) its infrequency due to lack of old oaks, b) a severe shortage of intermediate aged oaks to replace the old veteran oaks colonized by H. croceus, c) old oaks that are dying prematurely due to shading from surrounding trees and d) maintenance of parks, pastures and nature reserves sometimes results in damaged or dead oaks or parts of oaks being removed, which is also unfavorable at the sites where the species occurs.
Old oaks colonized by H. croceus and other potential veteran oak trees must be protected. Entire stands of uneven-aged oak must be preserved in landscapes where H. croceus occurs.
A better knowledge of the species ecology, in particular its population biology; at what conditions does it establish, its potential to successfully disperse and colonize at low population densities. Research should also be conducted to investigate the potential to establish H . croceus by mycelial inocculation into oaks.
Dahlberg A & Croneborg H. 2003. 33 threatened fungi in Europe. Complementary and revised information on candidates for listing in Appendix I of the Bern Convention T-PVS (2001) 34 rev 2.
Artsdatabanken 2010. Safrankjukem,Hapalopilus croceus (Fact sheet in Norwegian). Artsdatabankens faktaark ISSN1504-9140 nr. 137, Tronheim, Norway. http://www2.artsdatabanken.no/faktaark/Faktaark137.pdf
ArtDatabanken 2012. Hapalopilus croceus, saffransticka (Fact sheet in Swedish).Uppsala, Sweden. http://www.artfakta.se/Artfaktablad/Hapalopilus_Croceus_121.pdf
Gärdenfors, U (ed), 2010. Red-listed Species in Sweden 2010. ArtDatabanken, SLU, Uppsala.
Kålås J A, Viken V, Henriksen S and. Skjelseth S (eds). 2010. Norwegian Biodiversity Information Centre, Norway. 480 pages.
Otto P, 2011. Ecology and chorology of 51 selected fungal species. Draft, Leipzig (unpublished)