Let sleeping logs lie: Beta diversity increases in deadwood beetle communities over time

Research Highlight: Seibold, S., Weisser, W., Ambarli, D., Gossner, M. M., Mori, A., Cadotte, M., Hagge, J., Bässler, C. & Thorn, S. (2022). Drivers of community assembly change during succession in wood-decomposing beetle communities. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13843. Paradigms of succession and its drivers have largely developed from systems relying on living plants. A substantial portion of terrestrial biodiversity and biomass exists in detrital systems that rely on dead organic matter, yet successional patterns in detrital systems have received far less attention. In particular, deadwood significantly contributes to forest ecosystem nutrient cycling and storage and represents a relatively long-lived detrital system in which to study patterns of succession. Seibold et al. examined successional patterns of deadwood beetle communities over 8 years in a large-scale experiment that included 379 logs from 13 different tree species in 30 forest stands in three regions of Germany. They predicted that deadwood beetle communities would initially differ among deadwood tree species, across space, and with climatic differences but would become more similar over time as deadwood decomposed and characteristics of remaining habitat become more homogeneous. However, Seibold et al. predicted that beetle communities would become increasingly different across space along deadwood succession if late successional species were weaker dispersers than early successional species. Surprisingly, beetle communities became more dissimilar over time contrary to predictions. But, as predicted, increasing phylogenetic distance among tree species led to increasingly dissimilar deadwood beetle communities. Lastly, differences across space, forest structure and climate led to different deadwood beetle communities, but these effects remained constant over time. These results suggest that deadwood succession is influenced by both deterministic and stochastic processes and that stochastic processes may be increasingly important in late successional stages. Seibold et al. reveal important drivers of detrital successional patterns in deadwood that indicate that deadwood beetle biodiversity can be promoted via maintaining a diversity of deadwood decay stages across a large phylogenetic diversity of trees species and structurally diverse forests. Future studies that test the mechanisms driving these patterns and whether these results hold for other saproxylic organisms will help inform forest conservation and management strategies.

Dipteran (Bibionomorpha and Tipulomorpha) diversity in dead wood in Lithuania

The aim of this study is to compile the species list of Bibionomorpha and Tipulomorpha flies associated with dead wood in Lithuania. Saproxylic nematocerans were studied from 2014 to 2020 in four protected areas and in five different tree species (Populustremula, Quercusrobur, Tiliacordata, Fraxinusexcelsior and Alnusglutinosa) of the second stage of decay by using emergence traps. In total, 113 species were identified with Mycetophilidae, Sciaridae and Limoniidae being the most species-rich families. The compiled list of species emerging from dead wood in Lithuania is presented. Fourteen species were reared from dead wood for the first time.

Legacies of invertebrate exclusion and tree secondary metabolites control fungal communities in dead wood

During decomposition of organic matter, microbial communities may follow different successional trajectories depending on the initial environment and colonizers. The timing and order of the species arrival (assembly history) can lead to divergent communities through priority effects. We explored how assembly history and resource quality affected fungal communities and decay rate of decomposing wood, 1.5 and 4.5 years after tree felling. Additionally, we investigated the effect of invertebrate exclusion during the first two summers. We measured initial resource quality of bark and wood of aspen (Populus tremula) logs and surveyed the fungal communities by DNA metabarcoding at different times during succession. We found that gradients in fungal community composition were related to resource quality and discuss how this may reflect different fungal life history strategies. As with previous studies, the initial amount of bark tannins was negatively correlated with wood decomposition rate over 4.5 years. The initial fungal community explained variation in community composition after 1.5, but not 4.5 years, of succession. Although the assembly history of initial colonizers may cause alternate trajectories in successional communities, our results indicate that the communities may converge with the arrival of secondary colonizers. We also identified a strong legacy of invertebrate exclusion on fungal communities, even after 4.5 years of succession, thereby adding crucial knowledge on the importance of invertebrates in affecting fungal community development. By measuring and manipulating aspects of assembly history and resource quality that have rarely been studied, we expand our understanding of the complexity of fungal community dynamics.

Influence of tree hollow characteristics and forest structure on saproxylic beetle diversity in tree hollows in managed forests in a regional comparison

Tree hollows are among the rarest habitats in today's Central European managed forests but are considered key structures for high biodiversity in forests. To analyze and compare the effects of tree hollow characteristics and forest structure on diversity of saproxylic beetles in tree hollows in differently structured managed forests, we examined between 41 and 50 tree hollows in beech trees in each of three state forest management districts in Germany. During the two-year study, we collected 283 saproxylic beetle species (5880 individuals; 22% threatened species), using emergence traps. At small spatial scales, the size of hollow entrance and the number of surrounding microhabitat structures positively influenced beetle diversity, while the stage of wood mould decomposition had a negative influence, across all three forest districts. We utilized forest inventory data to analyze the effects of forest structure in radii of 50-500 m around tree hollows on saproxylic beetle diversity in the hollows. At these larger spatial scales, the three forest management districts differed remarkably regarding the parameters that influenced saproxylic beetle diversity in tree hollows. In Ebrach, characterized by mostly deciduous trees, the amount of dead wood positively influenced beetle diversity. In the mostly coniferous Fichtelberg forest district, with highly isolated tree hollows, in contrast, only the proportion of beech trees around the focal tree hollows showed a positive influence on beetle diversity. In Kelheim, characterized by mixed forest stands, there were no significant relationships between forest structure and beetle diversity in tree hollows. In this study, the same local tree hollow parameters influenced saproxylic beetle diversity in all three study regions, while parameters of forest structure at larger spatial scales differed in their importance, depending on tree-species composition.

[Spatial distribution and associations of dead woods in natural spruce-fir secondary forests]

To reveal the community succession rule of natural secondary forest, we investigated basic characteristics and coordinates of each tree (DBH≥1 cm) within a plot (100 m×100 m) using the adjacent grid method and examined the distribution pattern and spatial associations of dead woods in a natural spruce-fir secondary forest in Jingouling Forest Farm, Wangqing Forestry Bureau, Jilin Province, China. The results showed that the diameter class distribution of dead woods showed the pattern of left single-peak curve, while the logs showed the pattern of multi-peak curve. The relationship between the abundance of dead woods and the standing individuals of a particular species was inconsistent. There was a significant negative exponential relationship between the number of dead woods and mixing degree of trees. The distribution of dead woods was concentrated at the 0-8 m scale. With the increases of scale, it gradually changed to random or uniform, with the random distribution being dominant. The aggregation distribution of dead woods with middle (10 cm≤DBH＜20 cm) and small (1 cm≤DBH＜10 cm) DBH was the main reason for the aggregation distribution of dead woods at small scale below 8 m. The spatial associations between dead woods and stan-ding trees at different diameter classes were significantly different. The relationship between dead woods and saplings (1 cm≤DBH＜5 cm) was closely correlated. The dead woods with large DBH and saplings showed a significant positive association at 2-25 m scale. There was no spatial association between dead woods and small trees (5 cm≤DBH＜15 cm). At the 0-3 m scale, there was a positive association between the middle trees (15 cm≤DBH＜25 cm) and dead woods of small and middle DBH. At the 9, 11-14 and 15, 42-45 m scales, dead woods of small and middle DBH were significantly negatively associated with large trees (DBH≥25 cm). In conclusion, biological traits, diameter class distribution, and spatial distribution affected the abundance and diameter class distribution of dead woods. The species with low mixing degree tended to have more dead woods. The diameter and scale would affect the spatial distribution of dead woods. The spatial correlation between dead woods and standing trees varied across diameter classes and scales.

What Are the Most Important Factors Influencing Springtail Tetrodontophora bielanensis?

Simple Summary

Springtails (Collembola) are organisms which mainly inhabit soil and litter layers but may account for around 25% of the canopy fauna. They can be also found in dead wood, which provides nutrients for these detritivores. The springtail, Tetrodontophora bielanensis, dwells in the litter and upper soil layers. In our research, we were focused on the environmental factors influencing this springtail in forests at the landscape and site level. We found that the springtail was positively influenced by the presence of Norway spruce (Picea abies) and with greater abundance in the south-eastern part of Krkonoše (Czech Republic). The negative influence of bark coverage, the presence of fungi, and the positive influence of an increasing circumference of tree was observed at the site level.

Abstract

The springtail, Tetrodontophora bielanensis, dwells in the litter and upper soil layers. This arthropod mainly inhabits humid litter and soil and prefers a cold climate. We determined the main factors influencing this springtail in forests at the landscape level in Krkonoše and site level in Orlické hory in the Czech Republic. We used passive trunk-tree traps. These traps are highly effective for sampling flightless fauna. We used 128 traps in Krkonoše and 17 traps in Orlické hory. The springtail was significantly positively influenced by the presence of Norway spruce (Picea abies) at the landscape level. Springtails’ abundance was, furthermore, influenced by the spatial distribution of the sampling sites. The negative influence of bark coverage and the presence of fungi, and positive influence of an increasing dimension of trees were significant at the site level. We argue for a more diversified management of mountainous forests with respect to forest history. This appears to be also important for mountainous forests in protected areas.

Sharpening species boundaries in the Micarea prasina group, with a new circumscription of the type species M. prasina

Micarea is a lichenized genus in the family Pilocarpaceae (Ascomycota). We studied the phylogeny and reassessed the current taxonomy of the M. prasina group. We focused especially on the taxonomic questions concerning the type species M. prasina and, furthermore, challenges concerning type specimens that are too old for successful DNA barcoding and molecular studies. The phylogeny was reconstructed using nuc rDNA internal transcribed spacer region (ITS1-5.8S-ITS2 = ITS), mitochrondrial rDNA small subunit (mtSSU), and replication licensing factor MCM7 gene from 31 species. Fifty-six new sequences were generated. The data were analyzed using maximum parsimony and maximum likelihood methods. The results revealed four undescribed, well-supported lineages. Three lineages represent new species described here as M. fallax, M. flavoleprosa, and M. pusilla. In addition, our results support the recognition of M. melanobola as a distinct species. Micarea fallax is characterized by a vivid to olive green thallus composed of aggregated granules and whitish or brownish apothecia sometimes with grayish tinge (Sedifolia-gray pigment).Micarea flavoleprosa has a thick, wide-spreading yellowish green, whitish green to olive green sorediate thallus and lacks the Sedifolia-gray pigmentation. The species is mostly anamorphic, developing apothecia rarely. Micarea melanobola is characterized by a pale to dark vivid green granular thallus and darkly pigmented apothecia (Sedifolia-gray). Micarea pusilla is characterized by a whitish green to olive green thinly granular or membranous thallus, numerous and very small whitish apothecia lacking the Sedifolia-gray pigment, and by the production of methoxymicareic acid. Micarea fallax, M. flavoleprosa, and M. melanobola produce micareic acid. The reliability of crystalline granules as a character for species delimitation was investigated and was highly informative for linking the old type specimen of M. prasina to fresh material.

Estimating uncertainty in the volume and carbon storage of downed coarse woody debris

Downed coarse woody debris, also known as coarse woody detritus or downed dead wood, is challenging to estimate for many reasons, including irregular shapes, multiple stages of decay, and the difficulty of identifying species. In addition, some properties are commonly not measured, such as wood density and carbon concentration. As a result, there have been few previous evaluations of uncertainty in estimates of downed coarse woody debris, which are necessary for analysis and interpretation of the data. To address this shortcoming, we quantified uncertainties in estimates of downed coarse woody debris volume and carbon storage using data collected from permanent forest inventory plots in the northeastern United States by the Forest Inventory and Analysis program of the USDA Forest Service. Quality assurance data collected from blind remeasurement audits were used to quantify error in diameter measurements, hollowness of logs, species identification, and decay class determination. Uncertainty estimates for density, collapse ratio, and carbon concentration were taken from the literature. Estimates of individual sources of uncertainty were combined using Monte Carlo methods. Volume estimates were more reliable than carbon storage, with an average 95% confidence interval of 15.9 m³ /ha across the 79 plots evaluated, which was less than the mean of 31.2 m³ /ha. Estimates of carbon storage (and mass) were more uncertain, due to poorly constrained estimates of the density of wood. For carbon storage, the average 95% confidence interval was 11.1 Mg C/ha, which was larger than the mean of 4.6 Mg C/ha. Accounting for the collapse of dead wood as it decomposes would improve estimates of both volume and carbon storage. On the other hand, our analyses suggest that consideration of the hollowness of downed coarse woody debris pieces could be eliminated in this region, with little effect. This study demonstrates how uncertainty analysis can be used to quantify confidence in estimates and to help identify where best to allocate resources to improve monitoring designs.

Arthropod Facilitation by Wood-Boring Beetles: Spatio-temporal Distribution Mediated by a Twig-girdler Ecosystem Engineer

The twig-girdler beetle Oncideres albomarginata chamela (Chemsak and Giesbert) (Cerambycidae: Lamiinae) detaches branches of Spondias purpurea L. (Sapindales: Anacardiaceae) that fall on the forest floor or remain suspended on vegetation. Many wood-boring beetles also oviposit in these branches and larval development creates cavities that are abandoned when the adults emerge. The objective of this study was to evaluate the role of wood-boring beetles as facilitators by creating new habitats for arthropods, and test for vertical stratification and temporal variation of arthropods associated with S. purpurea branches that were previously engineered by O. albomarginata chamela in a tropical dry forest (TDF) in Jalisco, Mexico. In order to determine the effects of vertical strata and seasons on branch colonization by arthropods, we placed 60 branches on the forest floor (ground stratum) and 60 were placed in trees (vegetation stratum) from February to April (dry season), and from August to October 2016 (rainy season), for 240 branch samples in total. We collected 8,008 arthropods, which included 7,753 ants (14 species) and 255 nonsocial arthropods (80 species) from 13 different orders. We observed a greater arthropod abundance in the branches in the vegetation stratum in the dry season compared with the rainy season, whereas the richness and abundance of arthropods in the ground stratum were greater in the rainy season compared with the dry season. We concluded that wood-boring beetles are important habitat facilitators for arthropods, and that the vertical position of branches and the seasonal variations in TDFs differently affect the colonization of the abandoned cavities by arthropods.

Conservation value of low-productivity forests measured as the amount and diversity of dead wood and saproxylic beetles

In many managed landscapes, low-productivity land comprises most of the remaining relatively untouched areas, and is often over-represented within protected areas. The relationship between the productivity and conservational value of a site is poorly known; however, it has been hypothesized that biodiversity increases with productivity due to higher resource abundance or heterogeneity, and that the species communities of low-productivity land are a nested subset of communities from more productive land. We tested these hypotheses for dead-wood-dependent beetles by comparing their species richness and composition, as well as the amount and diversity of dead wood, between low-productivity (potential forest growth <1 m³ ·ha^-1 ·yr^-1 ) and high-productivity Scots pine-dominated stands in Sweden. We included four stand types: stands situated on (1) thin soils and (2) mires (both low-productivity), (3) managed stands, and (4) unmanaged stands set aside for conservation purposes (both high-productivity). Beetle species richness and number of red-listed species were highest in the high-productivity set-asides. Species richness was positively correlated with the volume and diversity of dead wood, but volume appeared to be a better predictor than diversity for the higher species richness in set-asides. Beetle species composition was similar among stand types, and the assemblages in low-productivity stands were largely subsets of those in high-productivity set-asides. However, 11% of all species and 40% of red-listed species only occurred in high-productivity stands, while no species were unique to low-productivity stands. We conclude that low-productivity forests are less valuable for conservation than high-productivity forest land. Given the generally similar species composition among stand types, a comparable conservational effect could be obtained by setting aside a larger area of low-productivity forest in comparison to the high-productivity. In terms of dead wood volumes, 1.8-3.6 ha of low-productivity forest has the same value as 1 ha of unmanaged high-productivity forest. This figure can be used to estimate the conservation value of low-productivity forests; however, as high-productivity forests harbored some unique species, they are not completely exchangeable.

Eleven remarkable Diptera species, emerged from fallen aspens in Kivach Nature Reserve, Russian Karelia

Background

In 2016, saproxylic Diptera associated with aspen (Populustremula L.) logs were studied in the Kivach Nature Reserve, Russian Karelia, using trunk emergence traps.

New information

Eleven rare species of Diptera (families Limoniidae, Scatopsidae, Axymyiidae, Mycetophilidae, Sciaridae, Platypezidae, Syrphidae and Clusiidae) with poorly known distribution and ecology were recorded. For each species, basic diagnostic characteristics were provided along with the information on microhabitats. An attempt was also undertaken to outline possible associations with wood-decaying macrofungi using nonparametric correlation.

Revealing hidden insect-fungus interactions; moderately specialized, modular and anti-nested detritivore networks

Ecological networks are composed of interacting communities that influence ecosystem structure and function. Fungi are the driving force for ecosystem processes such as decomposition and carbon sequestration in terrestrial habitats, and are strongly influenced by interactions with invertebrates. Yet, interactions in detritivore communities have rarely been considered from a network perspective. In the present study, we analyse the interaction networks between three functional guilds of fungi and insects sampled from dead wood. Using DNA metabarcoding to identify fungi, we reveal a diversity of interactions differing in specificity in the detritivore networks, involving three guilds of fungi. Plant pathogenic fungi were relatively unspecialized in their interactions with insects inhabiting dead wood, while interactions between the insects and wood-decay fungi exhibited the highest degree of specialization, which was similar to estimates for animal-mediated seed dispersal networks in previous studies. The low degree of specialization for insect symbiont fungi was unexpected. In general, the pooled insect-fungus networks were significantly more specialized, more modular and less nested than randomized networks. Thus, the detritivore networks had an unusual anti-nested structure. Future studies might corroborate whether this is a common aspect of networks based on interactions with fungi, possibly owing to their often intense competition for substrate.

Bacteria associated with decomposing dead wood in a natural temperate forest

Dead wood represents an important pool of organic matter in forests and is one of the sources of soil formation. It has been shown to harbour diverse communities of bacteria, but their roles in this habitat are still poorly understood. Here, we describe the bacterial communities in the dead wood of Abies alba, Picea abies and Fagus sylvatica in a temperate natural forest in Central Europe. An analysis of environmental factors showed that decomposing time along with pH and water content was the strongest drivers of community composition. Bacterial biomass positively correlated with N content and increased with decomposition along with the concurrent decrease in the fungal/bacterial biomass ratio. Rhizobiales and Acidobacteriales were abundant bacterial orders throughout the whole decay process, but many bacterial taxa were specific either for young (<15 years) or old dead wood. During early decomposition, bacterial genera able to fix N2 and to use simple C1 compounds (e.g. Yersinia and Methylomonas) were frequent, while wood in advanced decay was rich in taxa typical of forest soils (e.g. Bradyrhizobium and Rhodoplanes). Although the bacterial contribution to dead wood turnover remains unclear, the community composition appears to reflect the changing conditions of the substrate and suggests broad metabolic capacities of its members.

Aphyllophoroid fungi in insular woodlands of eastern Ukraine

Background

Fungi play crucial roles in ecosystems and are among the species-richest organism groups on Earth. However, knowledge on their occurrence lags behind the data for animals and plants. Recent analyses of fungal occurrence data from Western, Central and Northern Europe provided important insights into response of fungi to global warming. The consequences of the global changes for biodiversity on a larger geographical scale are not yet understood. Landscapes of Eastern Europe and particularly of eastern Ukraine, with their specific geological history, vegetation and climate, can add substantially new information about fungal diversity in Europe.

New information

We describe the dataset and provide a checklist of aphyllophoroid fungi (non-gilled macroscopic Basidiomycota) from eastern Ukraine sampled in 16 areas between 2007 and 2011. The dataset was managed on the PlutoF biodiversity workbench (http://dx.doi.org/10.15156/BIO/587471) and can also be accessed via Global Biodiversity Information Facility (GBIF, parts of datasets https://doi.org/10.15468/kuspj6 and https://doi.org/10.15468/h7qtfd). This dataset includes 3418 occurences, namely 2727 specimens and 691 observations of fructifications belonging to 349 species of fungi. With these data, the digitised CWU herbarium (V. N. Karazin Kharkiv National University, Ukraine) doubled in size A most detailed description of the substrate's properties and habitat for each record is provided. The specimen records are supplemented by 26 nuclear ribosomal DNA ITS sequences and six 28S sequences. Additionally, 287 photographs depicting diagnostic macro- and microscopic features of fungal fruitbodies as well as studied habitats are linked to the dataset. Most of the specimens have at least one mention in literature and relevant references are displayed as associated with specimen data. In total, 16 publication references are linked to the dataset. The dataset sheds new light on the fungal diversity of Eastern Europe. It is expected to complement other public sources of fungal occurrence information on continental and global levels in addressing macroecological and biogeographical questions.

Impacts of salvage logging on biodiversity: a meta-analysis

Logging to "salvage" economic returns from forests affected by natural disturbances has become increasingly prevalent globally. Despite potential negative effects on biodiversity, salvage logging is often conducted, even in areas otherwise excluded from logging and reserved for nature conservation, inter alia because strategic priorities for post-disturbance management are widely lacking.A review of the existing literature revealed that most studies investigating the effects of salvage logging on biodiversity have been conducted less than 5 years following natural disturbances, and focused on non-saproxylic organisms.A meta-analysis across 24 species groups revealed that salvage logging significantly decreases numbers of species of eight taxonomic groups. Richness of dead wood dependent taxa (i.e. saproxylic organisms) decreased more strongly than richness of non-saproxylic taxa. In contrast, taxonomic groups typically associated with open habitats increased in the number of species after salvage logging.By analysing 134 original species abundance matrices, we demonstrate that salvage logging significantly alters community composition in 7 of 17 species groups, particularly affecting saproxylic assemblages.Synthesis and applications. Our results suggest that salvage logging is not consistent with the management objectives of protected areas. Substantial changes, such as the retention of dead wood in naturally disturbed forests, are needed to support biodiversity. Future research should investigate the amount and spatio-temporal distribution of retained dead wood needed to maintain all components of biodiversity.

Forest management could counteract distribution retractions forced by climate change

Climate change is expected to drive the distribution retraction of northern species. However, particularly in regions with a history of intensive exploitation, changes in habitat management could facilitate distribution expansions counter to expectations under climate change. Here, we test the potential for future forest management to facilitate the southward expansion of an old-forest species from the boreal region into the boreo-nemoral region, contrary to expectations under climate change. We used an ensemble of species distribution models based on citizen science data to project the response of Phellinus ferrugineofuscus, a red-listed old-growth indicator, wood-decaying fungus, to six forest management and climate change scenarios. We projected change in habitat suitability across the boreal and boreo-nemoral regions of Sweden for the period 2020-2100. Scenarios varied in the proportion of forest set aside from production, the level of timber extraction, and the magnitude of climate change. Habitat suitabilities for the study species were projected to show larger relative increases over time in the boreo-nemoral region compared to the boreal region, under all scenarios. By 2100, mean suitabilities in set-aside forest in the boreo-nemoral region were similar to the suitabilities projected for set-aside forest in the boreal region in 2020, suggesting that occurrence in the boreo-nemoral region could be increased. However, across all scenarios, consistently higher projected suitabilities in set-aside forest in the boreal region indicated that the boreal region remained the species stronghold. Furthermore, negative effects of climate change were evident in the boreal region, and projections suggested that climatic changes may eventually counteract the positive effects of forest management in the boreo-nemoral region. Our results suggest that the current rarity of this old-growth indicator species in the boreo-nemoral region may be due to the history of intensive forestry. Forest management therefore has the potential to compensate for the negative effects of climate change. However, increased occurrence at the southern range edge would depend on the dispersal and colonization ability of the species. An increase in the amount of set-aside forest across both the boreal and boreo-nemoral regions is therefore likely to be required to prevent the decline of old-forest species under climate change.

Postfire Succession of Ants (Hymenoptera: Formicidae) Nesting in Dead Wood of Northern Boreal Forest

Dead wood decomposition begins immediately after tree death and involves a large array of invertebrates. Ecological successions are still poorly known for saproxylic organisms, particularly in boreal forests. We investigated the use of dead wood as nesting sites for ants along a 60-yr postfire chronosequence in northeastern coniferous forests. We sampled a total of 1,625 pieces of dead wood, in which 263 ant nests were found. Overall, ant abundance increased during the first 30 yr after wildfire, and then declined. Leptothorax cf. canadensis Provancher, the most abundant species in our study, was absent during the first 2 yr postfire, but increased steadily until 30 yr after fire, whereas Myrmica alaskensis Wheeler, second in abundance, was found at all stages of succession in the chronosequence. Six other species were less frequently found, among which Camponotus herculeanus (Linné), Formica neorufibarbis Emery, and Formica aserva Forel were locally abundant, but more scarcely distributed. Dead wood lying on the ground and showing numerous woodborer holes had a higher probability of being colonized by ants. The C:N ratio was lower for dead wood colonized by ants than for noncolonized dead wood, showing that the continuous occupation of dead wood by ants influences the carbon and nitrogen dynamics of dead wood after wildfire in northern boreal forests.

Identification of Eastern United States Reticulitermes Termite Species via PCR-RFLP, Assessed Using Training and Test Data

Reticulitermes termites play key roles in dead wood decomposition and nutrient cycling in forests. They also damage man-made structures, resulting in considerable economic loss. In the eastern United States, five species (R. flavipes, R. virginicus, R. nelsonae, R. hageni and R. malletei) have overlapping ranges and are difficult to distinguish morphologically. Here we present a molecular tool for species identification. It is based on polymerase chain reaction (PCR) amplification of a section of the mitochondrial cytochrome oxidase subunit II gene, followed by a three-enzyme restriction fragment length polymorphism (RFLP) assay, with banding patterns resolved via agarose gel electrophoresis. The assay was designed using a large set of training data obtained from a public DNA sequence database, then evaluated using an independent test panel of Reticulitermes from the Southern Appalachian Mountains, for which species assignments were determined via phylogenetic comparison to reference sequences. After refining the interpretive framework, the PCR-RFLP assay was shown to provide accurate identification of four co-occurring species (the fifth species, R. hageni, was absent from the test panel, so accuracy cannot yet be extended to training data). The assay is cost- and time-efficient, and will help improve knowledge of Reticulitermes species distributions.

Association of extinction risk of saproxylic beetles with ecological degradation of forests in Europe

To reduce future loss of biodiversity and to allocate conservation funds effectively, the major drivers behind large-scale extinction processes must be identified. A promising approach is to link the red-list status of species and specific traits that connect species of functionally important taxa or guilds to resources they rely on. Such traits can be used to detect the influence of anthropogenic ecosystem changes and conservation efforts on species, which allows for practical recommendations for conservation. We modeled the German Red List categories as an ordinal index of extinction risk of 1025 saproxylic beetles with a proportional-odds linear mixed-effects model for ordered categorical responses. In this model, we estimated fixed effects for intrinsic traits characterizing species biology, required resources, and distribution with phylogenetically correlated random intercepts. The model also allowed predictions of extinction risk for species with no red-list category. Our model revealed a higher extinction risk for lowland and large species as well as for species that rely on wood of large diameter, broad-leaved trees, or open canopy. These results mirror well the ecological degradation of European forests over the last centuries caused by modern forestry, that is the conversion of natural broad-leaved forests to dense conifer-dominated forests and the loss of old growth and dead wood. Therefore, conservation activities aimed at saproxylic beetles in all types of forests in Central and Western Europe should focus on lowlands, and habitat management of forest stands should aim at increasing the amount of dead wood of large diameter, dead wood of broad-leaved trees, and dead wood in sunny areas.

Phylogeography of Saproxylic and Forest Floor Invertebrates from Tallaganda, South-eastern Australia

The interaction between physiogeographic landscape context and certain life history characteristics, particularly dispersal ability, can generate predictable outcomes for how species responded to Pleistocene (and earlier) climatic changes. Furthermore, the extent to which impacts of past landscape-level changes ‘scale-up’ to whole communities has begun to be addressed via comparative phylogeographic analyses of co-distributed species. Here we present an overview of a body of research on flightless low-mobility forest invertebrates, focusing on two springtails and two terrestrial flatworms, from Tallaganda on the Great Dividing Range of south-eastern Australia. These species are distantly-related, and represent contrasting trophic levels (i.e., slime-mold-grazers vs. higher-level predators). However, they share an association with the dead wood (saproxylic) habitat. Spatial patterns of intraspecific genetic diversity partly conform to topography-based divisions that circumscribe five ‘microgeographic regions’ at Tallaganda. In synthesizing population processes and past events that generated contemporary spatial patterns of genetic diversity in these forest floor invertebrates, we highlight cases of phylogeographic congruence, pseudo-congruence, and incongruence. Finally, we propose conservation-oriented recommendations for the prioritisation of areas for protection.

Accounting for density reduction and structural loss in standing dead trees: Implications for forest biomass and carbon stock estimates in the United States

BACKGROUND

Standing dead trees are one component of forest ecosystem dead wood carbon (C) pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas Inventory. Initiated in 1998, the USDA Forest Service's Forest Inventory and Analysis program (responsible for compiling the Nation's forest C estimates) began consistent nationwide sampling of standing dead trees, which may now supplant previous purely model-based approaches to standing dead biomass and C stock estimation. A substantial hurdle to estimating standing dead tree biomass and C attributes is that traditional estimation procedures are based on merchantability paradigms that may not reflect density reductions or structural loss due to decomposition common in standing dead trees. The goal of this study was to incorporate standing dead tree adjustments into the current estimation procedures and assess how biomass and C stocks change at multiple spatial scales.

RESULTS

Accounting for decay and structural loss in standing dead trees significantly decreased tree- and plot-level C stock estimates (and subsequent C stocks) by decay class and tree component. At a regional scale, incorporating adjustment factors decreased standing dead quaking aspen biomass estimates by almost 50 percent in the Lake States and Douglas-fir estimates by more than 36 percent in the Pacific Northwest.

CONCLUSIONS

Substantial overestimates of standing dead tree biomass and C stocks occur when one does not account for density reductions or structural loss. Forest inventory estimation procedures that are descended from merchantability standards may need to be revised toward a more holistic approach to determining standing dead tree biomass and C attributes (i.e., attributes of tree biomass outside of sawlog portions). Incorporating density reductions and structural loss adjustments reduces uncertainty associated with standing dead tree biomass and C while improving consistency with field methods and documentation.