%0 Research article
%T Old-forest species: the importance of specific substrata vs. stand continuity in the case of calicioid fungi
%A Lõhmus, Asko
%A Lõhmus, Piret
%D 2011
%J Silva Fennica
%V 45
%N 5
%R doi:10.14214/sf.84
%U https://silvafennica.fi/article/84
%X Appropriate conservation management of old-forest species depends on the  causes of their old-forest affinity, which, however, are insufficiently  known. Calicioid fungi are often considered old-forest dependent  because of their special requirements for microhabitat, microclimate,  and stand continuity for at least two tree generations. We demonstrate  that, for several methodological or interpretational problems, published  studies do not provide unequivocal evidence for such mechanisms and  even for old-forest dependency of calicioids in general. We then analyse  a large Estonian dataset (ca. 2300 records of 32 species) representing  various management types and site types to answer whether old forests  have more calicioid species, and any specific species, than could be  expected for the substratum availability observed. Although old growth  had more species and records than mature managed stands or cutover  sites, those substratum types that occurred at roughly similar  abundances also hosted comparable numbers of species in different  management types. The characteristic substrata adding extra species to  old growth were snags and root-plates of treefall mounds; wood surfaces  in general comprised more than half of all calicioid records. Although  substratum abundance did not fully explain the species-richness contrast  between old growth and mature stands, additional evidence suggested  that the unexplained variance is rather due to small-scale habitat  characteristics than stand-scale continuity or microclimate. Finally, we  review the evidence for old-forest affinity of calicioid species and  distinguish a set of threatened species. We conclude that the  availability of specific substrata is the main limiting factor for  calicioid fungi in forests, and its quantitative and stochastic nature  explains the large random and region-specific variation in the published  lists of ‘old-forest species’.