Dead Wood Substrates Research Articles

Fungal and beetle diversity in deciduous fine woody debris in spruce-dominated forests in relation to substrate quantity and quality

AbstractDeciduous fine woody debris (DFWD) is a common deadwood substrate type in boreal conifer-dominated forests, but it is usually present in low volumes, and its importance for deadwood dependent biodiversity is poorly understood. In this study, we investigated how DFWD-associated fungal and beetle diversity depends on local substrate availability and quality, and how species diversity differs between DFWD and coarse deciduous deadwood (birch logs) in boreal mixed spruce-dominated forests in southern Finland. We studied 25 forest plots (each 0.16 ha), measuring and sampling all pieces of DFWD with a diameter of 2–5 cm and minimum length of 50 cm. Wood-inhabiting fungi were surveyed from wood samples by DNA metabarcoding and saproxylic beetles were surveyed by bark sieving. Our results showed a clear positive relationship between DFWD abundance and the diversity of fungi and beetles. Tree species and decay class diversity were not important in explaining fungal and beetle diversity or community composition, possibly due to low degree of variation in DFWD quality among the study plots. DFWD hosted more diverse fungal assemblages than birch logs, including species of conservation concern, while no red-listed beetle species were observed on DFWD. Overall, species assemblages associated with fine and coarse deciduous deadwood were non-nested. Thus, DFWD represents a non-redundant complementary deadwood resource type alongside coarse deciduous deadwood in boreal forests.

The role of deadwood substrates in promoting moss growth: Decay class and particle size effects

AbstractPlagiomnium acutum has a high value of landscape application and medicinal value, but there is a lack of related research on propagation and cultivation techniques. The deadwood substrate has rich nutrients and superior water retention properties, which will be conducive to promoting the growth of moss. Nevertheless, the underlying mechanisms by which deadwood influences moss growth are not yet fully unclear. In this study, we pulverized deadwood from five decay classes of Pinus massoniana into three distinct particle sizes. Through a pot experiment, we investigated the effects of decay class and physicochemical properties on the growth and physiology of Plagiomnium acutum, aiming to identify the most suitable growth substrate. The results indicated that both the decay class and particle diameter of deadwood significantly affect the substrate's physicochemical characteristics and the growth indexes of P. acutum, with the decay class exerting a more pronounced effect. The water‐holding porosity, water‐holding capacity, total nitrogen, total phosphorus, total potassium and lignin content of the substrate positively affected the growth of P. acutum, while the bulk density, void ratio, total carbon, carbon‐to‐nitrogen ratio, condensed tannin content and cellulose content had negative impacts. A comprehensive evaluation using a fuzzy membership function indicated that deadwood with higher decay classes (IV and V) was more conducive to the growth of P. acutum. Specifically, substrates from decay class IV with particle sizes of 10–20 mm provided the most favorable conditions for P. acutum and were recommended as the optimal cultivation substrate. The results of this study provide theoretical basis and technical support for the propagation and cultivation of P. acutum, and provide a foundation for further development of the industrial, pharmaceutical and environmental biotechnology potential of P. acutum.

Forest fuel extraction does not affect macrolichens on deadwood substrates, but only if coarse woody debris is not collected

AbstractThe increasing use of forest fuels poses risks to biodiversity. Lichens that grow on deadwood may be affected as fuel extraction removes their substrates. We surveyed deadwood and macrolichens on deadwood in two types of clearcuts: sites in which forest fuels, stumps and slash, had been extracted, and standard clearcut sites, i.e. control sites with no fuel extraction. Extraction sites had 52% lower deadwood volume (44.3 m³/ha vs. 21.4 m³/ha) and 36% less deadwood surface area. However, the negative impact of fuel extraction on macrolichen species richness was low: 21.4 and 16.9 species on average were found in control and extraction sites, respectively. We found a clear positive relationship between macrolichen species richness and the surface area of logs, which are usually not targeted by forest fuel extraction. Species composition varied more among extraction sites than control sites and differed between all the studied deadwood types. Species of Cladonia were associated with stumps, while species in the family Parmeliaceae were associated with logs. Slash was of negligible importance to macrolichens. Stumps may hold value, particularly if large-sized deadwood is otherwise not available. Thus, we conclude that the extraction of slash poses no threat to macrolichen diversity, whereas extensive extraction of stumps can cause losses in lichen diversity. The loss of coarse woody debris during forest fuel extraction has negative effects on lichen diversity and should be avoided.

Delayed response of bryophytes to wind disturbance and salvage logging in hemiboreal mixed forests

Climate change accompanied by altered natural disturbance regimes threatens the resilience of boreal and hemiboreal forests. Bryophytes, an important part of plant biomass and diversity, fulfill numerous important functions in forests, thus markedly contributing to the resilience of these ecosystems. We studied abundance, richness, diversity and community composition of bryophyte species 20–21 years after wind disturbance in moderately damaged, heavily damaged and heavily damaged and subsequently salvage-logged stands; overmature forest stands with similar tree species composition were included in the study as a reference group. The community characteristics were linked with treatment and accompanying environmental variables. Altogether, 108 bryophyte taxa (81 mosses and 27 liverworts) were identified in study plots. We found that bryophytes responded to windthrow severity level and salvage logging in terms of species richness, diversity, and composition; diversity of microhabitats was the most important environmental variable explaining the variation in diversity metrics. Besides exhibiting greater overall species richness, uncleared wind-disturbed plots contained more bryophyte species with high conservational value as well, compared to salvage-logged and control plots. The largest number of bryophyte taxa was associated with deadwood substrates. Ordination analysis further emphasized the importance of deadwood substrate for liverworts. In order to fulfill the objective of biodiversity conservation, wind-disturbed forests should be left to recover naturally, to ensure a favorable status of all naturally occurring species and to improve the status of endangered and rare species. Retaining a proportion of surviving and/or wind-damaged trees while salvaging might also alleviate the unfavorable environmental conditions for bryophyte species while “lifeboating” some species through the following successional stages.

Translocation of deadwood in ecological compensation: A novel way to compensate for habitat loss

Restoration of degraded habitat is frequently used in ecological compensation. However, ecological restoration suffers from innate problems of long delivery times of features shown to be good proxies for biodiversity, e.g., large dead trees. We tested a possible way to circumvent this problem; the translocation of hard-to-come deadwood substrates from an impact area to a compensation area. Following translocation, deadwood density in the compensation area was locally equivalent to the impact area, around 20 m3 ha−1, a threshold for supporting high biodiversity of rare and red-listed species. However, deadwood composition differed between the impact and compensation area, showing a need to include more deadwood types, e.g., late decomposition deadwood, in the translocation scheme. To guide future compensation efforts, the cost for translocation at different spatial scales was calculated. We conclude that translocation of deadwood could provide a cost-efficient new tool for ecological compensation/restoration but that the method needs refinement.

Diversity of beetle species and functional traits along gradients of deadwood suggests weak environmental filtering

BackgroundGradients in local environmental characteristics may favour the abundance of species with particular traits, while other species decline, or favour species with different traits at the same time, without an increase in average species abundances. Therefore, we asked: do variations in species and traits differ along gradients of deadwood variables? Do species abundance and trait occurrence change with species richness within or between functional groups? Thus, we analysed the beetle assemblages of five forest sites located in Italy, along the Apennines mountains. MethodsFrom 2012 to 2018 we sampled beetles and five deadwood types in 193 plots to characterise the deadwood gradient: standing dead trees, snags, dead downed trees, coarse woody debris, and stumps. We modelled beetle species relative abundances and trophic traits occurrences against the deadwood variables using joint species distribution models. ResultsOut of 462 species, only 77 showed significant responses to at least one deadwood type, with a weak mean response across species. Trophic groups showed mostly negative responses to deadwood variables. Species abundance increased with species richness among sites only for phytophagous and saproxylophagous. Trait occurrence did not increase with species richness among sites, except for phytophagous and saproxylophagous. However, trait occurrence changed significantly with species richness of several trophic groups within some sites. We found that increases in species richness do not result in decreases in species abundance of a given trophic group, but rather null or positive relationships were found suggesting low interspecific competition. ConclusionsOur findings suggest that in Mediterranean mountain forests there is still room for increasing the level of naturalness, at least for what concerns deadwood management. On one side, our findings suggest that competition for deadwood substrates is still low, on the other side they indicate that increasing deadwood volume and types to improve overall beetle richness may increase also beetle abundances.

Deadwood substrate and species-species interactions determine the release of volatile organic compounds by wood-decaying fungi

Wood-decaying fungi in the phylum Basidiomycota play a significant role in the global carbon cycle, as they decompose deadwood effectively. Fungi may compete for utilizable substrate and growth space by producing soluble metabolites and by releasing volatile organic compounds (VOCs). We determined the role of wood substrate (Scots pine or Norway spruce) on the generation of hyphal biomass, secreted metabolites and enzyme activities, wood decomposition rate, and fungal species-species interactions on VOC release. We studied one brown-rot species ( Fomitopsis pinicola ) and two white-rot species ( Phlebia radiata and Trichaptum abietinum ) cultivated individually or in combinations. Wood substrate quality influences VOC release by the wood-decaying fungi, with signature differences caused by the decomposition trait (brown rot or white rot) and species-species interactions. VOC release was higher in the cultures of Basidiomycota than in uncolonized sawdust. Fungal biomass, decomposition activity, iron reduction, enzyme activities, oxalate anion content, and oxalic acid production explained VOC release from decaying wood. • Species-species interactions of Basidiomycota accelerate sesquiterpene release. • Wood substrate quality affects VOC release. • VOC release depends on the decomposition trait and species-species interactions. • Decomposition activity, iron reduction and enzyme activities explained VOC release.

Climate Change Alters Temperate Forest Canopies and Indirectly Reshapes Arthropod Communities

Global change challenges the adaptive potential of forests. Large-scale alterations of forest canopies have been reported across Europe, and further modifications are expected in response to the predicted changes in drought and windstorm regimes. Since forest canopies are dynamic interfaces between atmosphere and land surface, communities of canopy-dwelling insects are at the forefront of major changes in response to both direct and indirect effects of climate change. First, we briefly introduce the factors shaping arthropod communities in the canopy of temperate forests. Second, we cover the significant impacts of a forest decline on canopy structure and functioning, and more specifically its contrasted effects on insect microhabitats, trophic resources and forest microclimates. Deleterious effects may be expected for several guilds of leaf-dwelling insects. Nonetheless, a forest decline could also lead to transient or long-lasting resource pulses for other canopy-dwelling guilds, especially saproxylic species depending on deadwood substrates and tree-related microhabitats. The novel microclimates may also become more favorable for some particular groups of insects. We pinpoint current knowledge gaps and the technological locks that should be undone to improve our understanding of the canopy biotope and biodiversity in temperate forests. We highlight the need for integrative approaches to reveal the mechanisms at play. We call for cross-scale studies and long-term collaborative research efforts, involving different disciplines such as community and disturbance ecology, plant and insect ecophysiology, and thermal ecology, to better anticipate ongoing functional and conservation issues in temperate forest ecosystems.

Bryophyte species composition at the stand scale (1 ha) – Differences between secondary stands half a century after clear-cutting and older semi-natural boreal forests

A growing proportion of the boreal biome consists of managed even-aged secondary forest stands regenerated after clear-cutting. Many disturbance-intolerant species may not be able to recolonize or reach their original abundance in these stands before the next clear-cutting, potentially causing large-scale biodiversity losses. Boreal bryophytes (mosses and liverworts) include many species intolerant to clear-cutting, and at small spatial scales species richness and occupancy has been shown to remain changed in secondary stands half a century after logging. To assess if such persistent changes occur also at the stand scale, we listed and estimated cover of all bryophyte species in 1-ha plots, comparing 14 secondary stands originating from clear-cutting 40–60 years earlier with 14 older semi-natural stands. The large plots also made it possible to assess differences in occupancy and abundance for more bryophyte species than in previous studies. Species composition differed significantly for both mosses and liverworts, but unlike earlier studies, we could not detect any significant difference between stand types in species numbers. Thirteen species were significantly associated with semi-natural stands and the total cover of liverworts was less than half in secondary stands. Secondary stands had significantly fewer species typically occurring under shady conditions and/or mostly growing on “tree substrates” (dead wood and/or bases and stems of living trees). Ordination analysis further emphasized the importance of shade and suitable deadwood substrates; the among-plot variation in bryophyte species composition was related to amount of coarse deadwood as well as to gradients from shady spruce dominated to open pine dominated stands and from polar- to equator-facing slopes. Besides lack of suitable habitat conditions in secondary stands, dispersal limitation may have caused a colonization time lag for some species. The clear importance of stand scale habitat conditions for bryophyte species composition calls for management adaptions to facilitate life boating and/or recolonization by ensuring availability of shade, coarse decomposing logs, and specific deciduous tree species (Populus, Salix, Sorbus) in secondary stands.

Substrate specificity among Diptera in decaying bioenergy wood: can they be conserved by the same measures as are currently applied to beetles?

Although threatened by forestry, our knowledge concerning saproxylic insects is strongly biased towards well-known orders, mainly beetles (Coleoptera). The beetles have, therefore, formed the basis on which conservation measures of other groups have been formulated. Despite being more species-rich, the Diptera have been rather neglected. Moreover, our limited knowledge of the Diptera suggests that their demands on the dead wood substrate differ markedly from that of coleopterans. We tested if this is true by comparing the substrate requirements of dipteran and coleopteran species by analysing the affinities of species assemblages for logging residues differing in age, size, and tree species. Insects were reared out from the same samples of bioenergy wood from clear-cuts in Sweden. 15 species of Brachyceran flies were compared with 56 species of Coleoptera. We found the average level of specialisation to be similar between the two groups, but the dipterans had (contrary to the expectations) a higher proportion of specialists. Affinities for differently aged wood were similar. More dipterans than beetles were associated with the coarsest wood (diameter 9 cm–15 cm). More dipterans than beetles tended to be associated with aspen (Populus tremula), while Coleoptera tended to be more associated than Diptera with oak (Quercus) and spruce (Picea abies). We conclude that most recommendations for conserving the saproxylic beetle fauna also seem to benefit dipterans, but that the dipterans might be even more sensitive to which qualities of the wood that is preserved. The high conservation value of aspen is already recognised and our results for dipterans strengthen this. The high incidence of many dipteran species in logging residues suggests that many dipterans use sun-exposed environments.

Common Cerambycid Pheromone Components as Attractants for Longhorn Beetles (Cerambycidae) Breeding in Ephemeral Oak Substrates in Northern Europe

Longhorn beetles are ecologically important insects in forest ecosystems as decomposers of woody substrates, microhabitat engineers, and as components of forest food webs. These species can be greatly affected both positively and negatively by modern forestry management practices, and should be monitored accordingly. Through headspace sampling, coupled gas chromatography-electroantennography, gas chromatography-mass spectrometry, and field bioassays, we identified two compounds, 2-methyl-1-butanol and 3-hydroxy-2-hexanone, that constitute aggregation-sex pheromone attractants of three cerambycid species which breed primarily in different types of fresh, recently dead oak wood in Northern Europe: Pyrrhidium sanguineum (L.), Phymatodes alni ssp. alni (L.), and Phymatodes testaceus (L.) (Cerambycinae: Callidiini). Analyses of headspace volatiles collected from live insects indicated that the male-produced aggregation-sex pheromone of P. sanguineum is a 1–15:100 blend of (R)-2-methyl-1-butanol and (R)-3-hydroxy-2-hexanone, whereas the corresponding ratios for P. alni were 70–110:100. In field bioassays, adult P. sanguineum and P. alni were significantly attracted to multiple blends with varying ratios of the two compounds. When tested individually, the compounds were minimally attractive. In contrast, adult P. testaceus exhibited nonspecific attraction to both of the individual compounds and to different blends, despite the hydroxyketone not being part of its pheromone, which consists of (R)-2-methyl-1-butanol alone. Overall, our results suggest that a blend of 50:100 of racemic 2-methyl-1-butanol and 3-hydroxy-2-hexanone is appropriate for parallel, cost-efficient pheromone-based monitoring of all three species. In particular, these species could serve as useful indicators of how modern forestry practices affect a whole guild of saproxylic insects that require ephemeral deadwood substrates for successful breeding.

Diversity of fungi in harvested forests 10 years after logging and burning: Polypore assemblages on different woody substrates

The negative biodiversity effects of timber- and biofuel-oriented forestry practices can be alleviated by leaving retention trees and logging residues following clear-cut harvests and occasionally including prescribed burns. Such measures can potentially maintain substrates especially for dead-wood-associated species during young, post-harvest successional stages. However, the availability and temporal patterns of different types of dead wood substrates after cutting are largely unknown, yet these patterns may have a major influence on fungal diversity.We sampled dead wood and the associated polypore fungi - a key wood decomposer group - in a large-scale field experiment with 24 sites, before logging and 2, 4 and 10 years after logging (clear-cut with and without retention trees) and burning. We investigated all old natural dead wood, stumps, slash and retention trees on each site, totaling 98,136 dead wood items. The data include 22,150 records of 122 polypore species collected across all sampling years.Ten years after treatments, we found no differences in the number of species between unlogged and logged or burned and unburned treatment categories, but on the treated sites, the numbers were higher than before treatments. Furthermore, the composition of species assemblages differed as the substrate types available varied between treatments. All dead wood substrate types hosted diverse polypore assemblages. The highest numbers of species were found on slash and retention trees. Furthermore, the polypore assemblages differed between dead wood types. Burning increased the number of species on stumps and red-listed species seemed to increase on burned sites.Our results show that dead wood can host diverse polypore assemblages also in managed forests after timber harvests. However, the pre-requisite for maintaining fungal diversity appears to be that – in addition to sufficient amount of substrates - also qualitative variation in dead wood substrates is maintained, including stumps and slash.

Mushroom species richness, distribution and substrate specificity in the Kilum-Ijim forest reserve of Cameroon

Objectives: Mushroom species richness, distribution and substrate specificity are essential considerations for conservation and management of forest ecosystems. In this study in the Kilum-Ijim mountain forest, mushroom species richness, distribution and substrate specificity was evaluated.Methodology and results: Fixed size plot method, opportunistic and downed wood sampling methods according to Mueller et al. (2004) was used for mushroom survey in 2015 in five sites in the Kilum-Ijim forest. The number of species, diversity in each site as well as substrate and morphotypes were recorded and calculated. A total of 393 macrofungi samples were collected. Highest collection (135) was recorded in September while January registered the least (22). Plantlife Sanctuary Oku recorded the highest number of macrofungal (109) while the least (44) was recorded in Anyajua community forest. Macrofungi were found on five varying substrates and ten different morphological forms of macrofungal were recorded.Conclusions and application of findings: Mushrooms species richness differed in the five sites surveyed in the Kilum-Ijim forest. Podoscypha petalodes had the highest number of species across all the five sites followed by Coprinus fissolanatus, Polyporus dictopus, Favolachia calocera and Xylaria sp. The Agaricaceae and Polyporaceae were the most abundant family. Majority of the mushroom species were found on dead wood substrate and few on dung and standing tree substrates. The result on species richness, distribution and substrate specificity of mushrooms widens the knowledge on mycodiversity and substrate relationship which is an important factor for conservation and utilization as well as for the sustainable forest ecosystem management. Also, the result projects the importance of geographic location of substrates on the distribution of mushrooms which is of immense value for conservation. There is variation in the substrate preferred by mushrooms and likely this factor influences the extent of occurrence and nutritional content.Keywords: Mushrooms, Species richness, Substrate, Distribution, Kilum-Ijim

Post-harvesting dynamics of the deadwood profile: the case of lowland beech-oak coppice-with-standards set-aside stands in France

In most European temperate forests, the heavy harvesting of low-quality wood for energy, a low minimum harvest diameter and a short rotation period, result in the limited deadwood resources. However, areas are being set aside in managed forests to restore deadwood levels. Coppice-with-standards is a silvicultural method characterized by periodic logging which clear-cuts coppice trees and removes some standard trees. We studied the deadwood profile (i.e., both amount and diversity) in oak-beech coppice-with-standards over time-since-the-last-harvest in order to evaluate how long it takes to recover significantly high amounts and diversity of deadwood substrates. A total of 282 circular 500-m2 plots were set up in 24 forests in southwestern France. We sampled five time-since-harvest classes within 80 years of the time elapsed since the last harvest. At the plot level, we used Generalized Linear Mixed Models to compare both deadwood volume and diversity among time classes. Diversity was also compared within time classes through accumulation curves. Deadwood legacies were very scarce after harvesting, both for volume and diversity. It took more than 70 years for deadwood amounts to become significantly higher than just after harvest; deadwood diversity was significantly higher only 30–50 years after harvesting due to quick snag recruitment. Crown deadwood, a particularly specialized resource rarely recorded, provided roughly 10–20% of the total deadwood amount throughout the study period and should be systematically recorded in further studies. Time-since-the-last-harvest was the best explanatory variable for both deadwood volume and diversity. We therefore recommend installing permanent set-aside areas to ensure deadwood conservation.

Bacteria inhabiting deadwood of 13 tree species are heterogeneously distributed between sapwood and heartwood.

Deadwood represents an important structural component of forest ecosystems, where it provides diverse niches for saproxylic biota. Although wood-inhabiting prokaryotes are involved in its degradation, knowledge about their diversity and the drivers of community structure is scarce. To explore the effect of deadwood substrate on microbial distribution, the present study focuses on the microbial communities of deadwood logs from 13 different tree species investigated using an amplicon based deep-sequencing analysis. Sapwood and heartwood communities were analysed separately and linked to various relevant wood physico-chemical parameters. Overall, Proteobacteria, Acidobacteria and Actinobacteria represented the most dominant phyla. Microbial OTU richness and community structure differed significantly between tree species and between sapwood and heartwood. These differences were more pronounced for heartwood than for sapwood. The pH value and water content were the most important drivers in both wood compartments. Overall, investigating numerous tree species and two compartments provided a remarkably comprehensive view of microbial diversity in deadwood.

Uneven-aged silviculture can enhance within stand heterogeneity and beetle diversity

Uneven-aged silviculture may better maintain species assemblages associated with old-growth forests than clear felling in part due to habitat heterogeneity created by maintaining standing retention strips adjacent to harvest trails. Retention strips and harvest trails created at the time of tree removal will likely have different microclimate and may harbor different assemblages. In some cases, the resultant stand heterogeneity associated with uneven-aged silviculture may be similar to natural small-scale disturbances. For beetles, increased light and temperature as well as potential access to young vegetation and deadwood substrates present in harvset trails may harbor beetle assemblages similar to those found in natural gaps. We sampled saproxylic beetles using flight intercept traps placed in harvest corridors and retention strips in 9 replicated uneven-aged spruce stands in central Sweden. We compared abundance, species richness and composition between harvest corridors and retention strips using generalized linear models, rarefaction, permutational multivariate analysis of variance and indicator species analysis. Canopy openness doubled, mean temperature and variability in daily temperature increased and humidity decreased on harvest trails. Beetle richness and abundance were greater in harvests trails than in retention strips and the beetle species composition differed significantly between habitats. Twenty-five species were associated with harvest trails, including three old-growth specialists such as Agathidium discoideum (Erichson), currently red-listed. We observed only one species, Xylechinus pilosus (Ratzeburg) that strongly favored retention strips. Harvest trails foster both open habitat species and old-growth species while retention strips harbored forest interior specialists. The combination of closed canopy, stratified forest in the retention strips and gap-like conditions on the harvest trails thus increases overall species richness and maintains more diverse assemblages at the stand level than would otherwise be seen in less heterogeneous stand types. This suggests that uneven-aged silviculture may provide added conservation benefits for both open habitat and old-growth specialists than silvicultural approaches that reduce stand heterogeneity.

Interactions between soil- and dead wood-inhabiting fungal communities during the decay of Norway spruce logs

We investigated the interaction between fungal communities of soil and dead wood substrates. For this, we applied molecular species identification and stable isotope tracking to both soil and decaying wood in an unmanaged boreal Norway spruce-dominated stand. Altogether, we recorded 1990 operational taxonomic units, out of which more than 600 were shared by both substrates and 589 were found to exclusively inhabit wood. On average the soil was more species-rich than the decaying wood, but the species richness in dead wood increased monotonically along the decay gradient, reaching the same species richness and community composition as soil in the late stages. Decaying logs at all decay stages locally influenced the fungal communities from soil, some fungal species occurring in soil only under decaying wood. Stable isotope analyses suggest that mycorrhizal species colonising dead wood in the late decay stages actively transfer nitrogen and carbon between soil and host plants. Most importantly, Piloderma sphaerosporum and Tylospora sp. mycorrhizal species were highly abundant in decayed wood. Soil- and wood-inhabiting fungal communities interact at all decay phases of wood that has important implications in fungal community dynamics and thus nutrient transportation.

Insights into the ecology, genetics and distribution of Lucanus elaphus Fabricius (Coleoptera: Lucanidae), North America's giant stag beetle

Abstract Little is known about the biology or conservation status of Lucanus elaphus Fabricius in North America despite well‐documented declines of a related species, Lucanus cervus (L.), in Europe. This study provides information critical to developing conservation plans for L. elaphus including the species’ larval substrate requirements, genetic data and range‐wide estimates of habitat suitability. In Mississippi floodplain forests, larval L. elaphus were recovered from a wide range of log sizes and rot types and were either found tunnelling within the wood or feeding beneath logs at the soil–wood interface. The species appears to require 1–2 years to complete development, exhibits a 1:1 sex ratio and is parasitised by Zelia vertebrata (Say) (Diptera: Tachinidae). Flight intercept traps placed at three heights at both the edge and interior of hardwood‐dominated forests in Georgia yielded six adult male L. elaphus, all of which were captured in traps placed at 15 m on the forest edge. Because L. elaphus larvae are morphologically indistinguishable from related species, DNA sequence data from the mitochondrial cytochrome oxidase I gene were generated to facilitate molecular identification. Genetic data revealed modest intra‐specific variation, with up to 1.3% sequence divergence among haplotypes sampled from the same forest. Based on assembled occurrence records, ecological niche models suggest that environmental conditions are suitable for L. elaphus across much of the southeastern United States, provided that adequate lowland forest cover and dead wood substrates are available.

Substrate age influences species richness and community composition of calicioid lichens and fungi on wooden buildings

Abstract Identifying processes that drive epiphytic lichen diversity and succession is important for directing conservation efforts and developing forest management plans for the maintenance of biodiversity and forest health. Stand age has been implicated as a key factor in driving epiphytic species diversity and community composition. However, understanding the influence of substrate age, independent of the many confounding variables that affect live and dead wood substrates in a forest habitat, can be difficult. To test the hypothesis that substrate age has distinct effects on lichen community assembly independent of surface area, we sampled communities of calicioid lichens and fungi growing on wooden buildings that ranged from 2 to 82 years old. We found a total of 17 species, with a strong positive correlation between species richness and substrate age. We also tested the effects of surface area on species richness and found no relationship between the two variables. Our results indicate that substrat...

Impact on species of conservation interest of forest harvesting for bioenergy purposes

Wood harvested from logging residues, pre-commercial and conservation thinnings is increasingly being used as biofuel as a substitute for fossil fuels. Here, we review the additional impact that wood harvesting for energy purposes has on species of conservation interest (SCI) in Swedish forests compared with the effects of conventional management, a perspective that largely has not been taken into consideration. We compiled data from 122 studies of forest fuel extraction with short- and long-term perspectives at the stand and landscape level to examine whether the effects on SCI are due to an additional loss of biodiversity as a result of cutting old forest or owing to competition from species that are favoured by the habitats formed by clearcutting. We also consider whether forest bioenergy extractions can be used to favour conservation values. The amount of logging residues has, in parallel to the amount of annually harvested trees, doubled during the past 50years in Sweden and constitutes the major source of dead wood for biodiversity in managed forests. Common wood-inhabiting species, predominantly fungi, beetles and other insects, and to some extent lichens, are the main species affected by wood harvesting for energy purposes. The main cause for the decline of SCI is the impact already imposed by conventional forest management: clearcutting old forest stands with subsequent soil scarification. Few SCI survive clear-felling because these species typically require other types of conditions and substrates than the new dead-wood substrate created after clear-felling. We conclude that the logging residues of conifers could potentially be harvested with small to negligible impacts on SCI. However, owing to the limited number of landscape level analyses that have been performed and the inherent difficulties of assessing the effects of wood harvesting on rare SCI, we suggest that these findings need to be treated with caution and that further studies should be undertaken. Hardwood conservation thinnings and brushwood harvest may improve conservation values. Developing operational guidelines to help to mitigate ecological damage to biodiversity should be based on cautionary principles and requires further large-scale and long-term research.