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Effective conservation strategies are needed to prevent further loss of biodiversity. This requires a comprehensive assessment of species' presence, distribution, and population sizes. Such assessments can be extremely challenging for species-rich taxa, like fungi, which are difficult to detect and identify. In recent years, metabarcoding applied to environmental samples has proven to be a promising method for fungal detection. However, its potential against traditional fruit body surveys in monitoring threatened fungal species has rarely been tested. Here, we utilized data on deadwood-inhabiting fungi from 569 deadwood objects across five sites in Central Europe to compare the effectiveness of fruit body surveys and metabarcoding (of low and high sampling intensity) in detecting threatened species. Across objects, sites, and per object, metabarcoding was more effective in detecting threatened species than fruit body surveys, regardless of sampling intensity. Eleven percent of all threatened species across all objects and sites could be detected by both methods, 70 % exclusively by metabarcoding and 18 % exclusively by fruit body surveys. The number of species detected by both methods on the same object was <4 %. Effects of high sampling intensity metabarcoding were stronger than low sampling intensity at object level. The effectiveness of the survey method was mainly independent of deadwood object characteristics. We suggest that metabarcoding is a valuable tool for threatened fungal species monitoring and conservation status assessments. However, for a comprehensive assessment, fruit body surveys are still needed, as this method detected a unique set of species and indicates the presence of vital fungal individuals. • Metabarcoding is an efficient method to detect threatened fungi in deadwood. • Metabarcoding and fruit body surveys detect different threatened fungal species. • To monitor threatened fungi, metabarcoding and fruit body surveys should be combined. [ABSTRACT FROM AUTHOR]

• Four tree-scale conservation outcomes of green-tree retention are distinguished. • 38% of retained trees had poor survival combined with low habitat value. • Large aspens had poor survival but supplied valuable dead wood substrate. • Well surviving European nemoral hardwood trees were worth retaining even when small. • Trees likely to develop microhabitats should be facilitated also at thinnings. Retention forestry is a silvicultural approach that can achieve both ecological and economic objectives in various forest ecosystems. It builds largely on the assumption that the live trees left unharvested (the main timber cost) effectively support ecological functioning of post-harvest forest. Such effectiveness can be understood as a combination of the initial ecological value of the tree (that may persist after tree death) and its survival, i.e., the prospect to develop into a high-quality veteran tree in the next forest generation. We assessed those aspects among >3000 live trees actually retained in 103 Estonian harvested sites and monitored over 16 years. We analysed how their survival and habitat value (estimated from tree morphology, confirmed by epiphyte surveys) translate to the veteran-tree perspectives. Only 48% of the trees were still alive after 16 years, and this final survival at the stand-scale was poorly predictable from a few years of monitoring. Only 12% retention trees had both high habitat value and high survival. Most trees (75%) were of low initial habitat value and, combined with low survival, almost 40% of all trees never provided quality habitat for tree-dwelling species. Nevertheless, we found considerable potential for post-harvest development of habitat value; notably in European nemoral hardwood species (such as Fraxinus, Quercus, Ulmus, Acer), which survived well but were usually in subcanopies at the time of the harvest. These findings indicate that retention forestry can improve also highly impoverished (e.g. short-rotation) forests, if analytical tools have been developed and applied to predict tree survival and future habitat quality. [ABSTRACT FROM AUTHOR]

Environmental managers often use indicator taxa to monitor full biodiversity and hidden environmental factors. For identifying practical indicators from assemblage data collected in the field, it is crucial to remove irrelevant variation, which unfortunately is not a common practice. We demonstrate, based on field data from Estonian forests, (i) how an attractive indicator group of macrofungi, perennial polypores, loses its apparent indicator value when variation in study effort and conspicuous environmental factors have been reduced; (ii) that simply including survey effort variation is sufficient to create significant covariation between species richness of taxon groups, which has often been taken as a justification for indicator assignment. These results imply that standardizing study effort should become a requirement for any field study that reports indicator taxa based on covariance patterns. We encourage researchers to be explicit and critical about the practical value of indicator taxa when compared with direct measurement of habitat conditions. [ABSTRACT FROM AUTHOR]

A major question in fungal conservation is why many species are confined to old forests, and how they could be supported by contemporary landscape matrix. Specifically, forestry that retains large biological legacies across landscape could reduce old-forest dependencies to species that require unusual substrate conditions. We sampled polypores in 112 2 ha plots (both old and harvested stands) in a semi-natural forestry context in Estonia and modelled the habitat factors of species confined to old growth. The results confirmed that old-growth assemblages emerged mostly due to diverse and abundant substrate supply (notably downed CWD). Only 10 species (five spruce-dwellers) were confined to old growth; of these, only Fomitopsis rosea and Oxyporus corticola were additionally affected by forest connectivity. The forestry system studied appeared particularly favourable for the species inhabiting deciduous wood. To better address habitat degradation in conservation, expert lists of ‘old-forest (indicator) fungi’ should be replaced with evidence-based focal taxa. [ABSTRACT FROM AUTHOR]

Antrodia is a polyphyletic genus, comprising brown-rot polypores with annual or short-lived perennial resupinate, dimitic basidiocarps. Here we focus on species that are closely related to Antrodia crassa , and investigate their phylogeny and species delimitation using geographic, ecological, morphological and molecular data (ITS and LSU rDNA, tef1 ). Phylogenetic analyses distinguished four clades within the monophyletic group of eleven conifer-inhabiting species (five described herein): (1) A. crassa s. str. (boreal Eurasia), Antrodia cincta sp. nova (North America) and Antrodia cretacea sp. nova (holarctic), all three being characterized by inamyloid skeletal hyphae that dissolve quickly in KOH solution; (2) Antrodia ignobilis sp. nova, Antrodia sitchensis and Antrodia sordida from North America, and Antrodia piceata sp. nova (previously considered conspecific with A. sitchensis ) from Eurasia, possessing amyloid skeletal hyphae; (3) Antrodia ladiana sp. nova from the southern part of the USA, Antrodia pinea from East Asia, and Antrodia ferox – so far known from subtropical North America, but here reported also from Eurasia. These three species have inamyloid hyphae and narrow basidiospores; (4) the North American Antrodia pini-cubensis , sharing similar morphological characters with A. pinea , forming a separate clade. The habitat data indicate that several species are threatened by intensive forestry. [ABSTRACT FROM AUTHOR]

In ecological and biodiversity research, fungal species are traditionally recorded using fruit body sampling, which underestimates mycelial presence of species. We hypothesized that fruit body based species lists are increasingly complete in larger sampling units where fruit bodies can be detected across multiple mycelial occurrences. We compared molecular records (detected with Illumina high-throughput sequencing) and records of fruit bodies of polypores in Estonian wetland pine forests. Of all molecularly detected polypores, 75% were present as conspecific fruit bodies within 30 m (including 24% on the same tree). This distance varied little among study sites. Despite lower costs, fruit body surveys yielded 60 polypore species, while sequencing only detected 13 species. Fruit body surveys of selected macrofungi can be thus efficient for biodiversity assessments. However, combining such surveys with high-throughput sequencing can add a broad description of the whole fungal assemblage even with limited samples (616 OTUs from 30 downed trunks in our study). [ABSTRACT FROM AUTHOR]

Abstract: Putatively old-forest dependent fungi have acquired a distinct position in biodiversity conservation, acting both as management targets and indicators for other nature values in the forest. Establishing old-forest dependency, however, requires rigorous sampling, taxonomy and identification approaches as exemplified here by a case study on Antrodia crassa. This rarely recorded polypore is considered indicative of old conifer forests in Northern Europe. We demonstrate that the material labelled as A. crassa includes not only frequent misidentifications, but it represents two genetically and ecologically distinct cryptic lineages with partly overlapping distributions. A balanced survey of different successional stages in Estonia indicated that one of those lineages prefers deadwood-rich disturbed habitats, notably clear-cuts, which have been previously undersampled. Because similar problems with cryptic lineages and biased surveys are common in mycological research, lists of ‘old-forest fungi’ should be considered as high-priority working hypotheses for taxonomic and ecological research, rather than well-established management tools. [Copyright &y& Elsevier]

Highlights: [•] Biodiversity consequences of the European ash dieback are hypothetical. [•] We show that the dieback can threaten local populations of ash dependent lichens. [•] Isolated ash-dependent populations of broader significance are of primary concern. [•] Silvicultural diversification is a major tool addressing tree dieback risks. [Copyright &y& Elsevier]

Abstract: The expanding practice of live-tree retention on clear-cuts represents a model case for conservation planning, because the high mortality of those trees requires balancing conflicting management goals in unpredictable conditions over long time frames. We explored the habitat provisioning function of dying retention trees for polypore and epixylic lichen assemblages. We sampled fallen trunks and snags created by known retention-tree deaths during the first post-harvest decade on 46 cut areas in Estonia, hemiboreal Europe. Those trees (particularly large fallen aspens) hosted a species-rich polypore assemblage that included several species of conservation concern. Lichen colonization of wood was slower and most species were found on pine snags. At the tree scale, the total species richness was highest on the trees that had died by trunk breakage creating both a snag and a log. To represent all species at the cutover scale, equal retention of different tree species and dead-wood types was sufficient for common species, but selective retention appeared necessary for species of conservation concern. The most frequent polypore species of conservation concern were either characteristic of specific substrates (notably aspen trunks) or early-successional stand conditions. We conclude that (i) dying retention trees are unlikely to provide dead-wood continuity at the stand scale and this function should be assessed at the landscape scale; (ii) effective habitat provisioning should include predicting and affecting the causes of tree death and linked management decisions based on the diversity, size, and longevity of the trees in specific landscape contexts. [Copyright &y& Elsevier]

• We measure the habitat relationships of wood-inhabiting fungi using DNA metabarcoding. • Old stands had larger species pools, at the landscape but not at the trunk scale. • High landscape-scale forest cover supported trunk scale fungal richness. • Increase in local dead-wood volume increased number of red-listed species per trunk. • Conservation conclusions based on DNA in wood same as in former fruit-body surveys. Understanding the distribution of biodiversity across forest landscapes is a key issue for the spatial planning of conservation management. Obtaining such spatial perspective is challenging because a large part of biodiversity remains hidden to the conventional survey approaches. High-productivity forests are probably the hotspots of hidden biodiversity and, at the same time, under severe timber harvesting pressure. We used DNA-metabarcoding approach to assess habitat quality of successional high productivity forests for wood-inhabiting fungi, focusing on fungal diversity that remains hidden in fruit-body surveys. We sampled a fixed amount of coarse fallen Norway spruce trunks in 40 naturally developing stands ranging from 44 to 140 years of age in hemi-boreal Estonia. We found three main habitat quality patterns. The total number of fungal OTUs in older (>80 years) stands exceeded that in younger stands due to the accumulation of rare fungi. The proportion of trunks hosting highest number of OTUs and trunk-scale richness of rare fungi were greatest in stands surrounded by extensive forest area. The average number of red-listed species per trunk increased mainly along with the volume of fallen dead wood; large volumes provided quality habitats already before the stands had reached 80 years of age. These results support the view that both substrate amount in the forest stand and habitat connectivity on a landscape scale support fungal diversity in dead wood. Earlier studies on wood-inhabiting fungi have reached similar conclusions based on observations of fungal fruit-bodies. Thus, the overall principle of focusing conservation efforts to remaining high quality habitats and landscapes extends to the fungi hidden to the conventional survey methods. [ABSTRACT FROM AUTHOR]