Old-forest species: the importance of specific substrata vs. stand continuity in the case of calicioid fungi

Abstract

Appropriate conservation management of old-forest species depends on the causes of their oldforest 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'.

Long-Term Impacts of Forest Ditching on Non-Aquatic Biodiversity: Conservation Perspectives for a Novel Ecosystem

“…Along with the testing of the effectiveness of those focal species, we call for collecting and analysing extensive empirical datasets in other regions of the world, notably on taxonomic groups not included in our study. This is important because of the apparently poor performance of traditional “experience-based” lists of focal species for forest management [46]. The same impression was obtained in our study when comparing the results with such lists previously published (e.g.…”

“…2), their main management questions at final felling are not related to drainage but to protecting important habitat structures. Studies in comparable site types indicate that those structures include, in particular, live trees of different species [77], large-sized downed deadwood [78], standing dead trees and windthrow mounds [46]. In addition to substrate provision, such structures may protect ground-layer cryptogams from mechanical disturbance [79].…”

“…Rather, bryophytes also benefited from ground-level heterogeneity [103] and/or the variability in shade conditions important for lichen diversity (e.g. [46]). …”

“…The study plots were arranged according to the principles of block design and they were selected as a part of a larger study representing several site types (see [45], [46] for details on plot selection). Each “block” included four 2-ha plots (four management types on one site type) in one forest region (a contiguous forest area on similar bedrock and terrain, and having a similar management history), and each plot represented a different stand.…”

Lichens and allied fungi new for Latvia

“…In all neighboring countries the species is known only from very few localities. In Estonia it has been assessed as vulnerable (Lõhmus & Lõhmus, 2011). In Lithuania the species was known from literature data and only recently was recorded in one locality (Motiejūnaitė et al, 2013).…”