Linking wood-decay fungal communities to decay rates: Using a long-term experimental manipulation of deadwood and canopy gaps

Decomposition transfers carbon (C) from detrital organic matter to soil and atmospheric pools. In forested ecosystems, deadwood accounts for a large proportion of the detrital C pool and is primarily decomposed by wood-inhabiting fungi (WIF). Deadwood reductions linked to forest harvesting may alter WIF richness and composition, thus indirectly influencing the persistence of deadwood and its contribution to C and nutrient cycling. Forest structure was enhanced via canopy gap creation and coarse woody debris (CWD) addition that mimic natural disturbance by windfall within a deciduous northern hardwood forest (Wisconsin, USA) to examine its effect on deadwood-associated biodiversity and function. Experimental sugar maple (Acer saccharum) logs were sampled, for DNA extraction, ten years after placement to determine the assembly of fungal community composition and its relationship to wood decay rates.Our findings suggest that the WIF community responded to gap disturbance by favoring species able to persist under more extreme microclimates caused by gaps. CWD addition under closed canopy tended to favor a different species assemblage from gap creation treatments and the control, where canopy was undisturbed and CWD was not added. This was presumably due to consistent microclimatic conditions and the abundance of CWD substrates for host specialists. Fungal OTU richness was significantly and inversely related to CWD decay rates, likely due to competition for resources. In contrast, fungal OTU composition was not significantly related to CWD decay rates, canopy openness or CWD addition amounts. Our study site represents a diverse fungal community in which complex interactions among wood-inhabiting organisms and abiotic factors are likely to slow CWD decomposition, which suggests that maintaining a biodiverse and microsite-rich ecosystem may enhance the capacity for C storage within temperate forests.     

Diversity of wood-inhabiting Agaricomycotina on wood of different size classes in riparian forests of Uruguay

Many Agaricomycotina species are saprobes, playing a fundamental role in nutrient cycling in forest ecosystems by decomposing wood. Little is known about factors affecting diversity of wood-inhabiting fungi in the neotropical, warm temperate native forests of Uruguay. Most of these native forests are riparian harboring about 300 tree species. In this study, we assessed the diversity of wood-inhabiting fungi on wood of different size classes in riparian forests of Uruguay. We recovered 186 species of Agaricomycotina, including 113 corticioid and 58 polyporoid taxa. Eleven taxa accounted for 38% of the all the samples. The highest number of species was found on fine woody debris (FWD, 2–10 cm diam) than coarse woody debris (CWD, >10 cm diam) and very fine woody debris (VFWD, <2 cm diam). Species-accumulation curves did not reach an asymptote for any of the groups or wood diameter classes studied. Polyporoids were more frequently recorded on CWD (61% of collections) and corticioids on VFWD (77%). Species richness estimated by non-parametric estimators indicates an Agaricomycotina species richness between 450 and 700 taxa. Our results show that Uruguayan riparian forests, despite its limited area and fragmentation, support a wood-inhabiting Agaricomycotina diversity comparable to less fragmented forests with more plant diversity.     

Understanding the distribution of wood-inhabiting fungi in European beech reserves from species-specific habitat models

We assessed how environmental drivers influence the occurrences of wood-inhabiting macrofungi in European beech forests, using an extensive dataset of fruit body records collected in 53 reserves across twelve European countries. We found that the 105 species included in this study varied greatly in their responses to covariates related to resource quality, climate and forest connectivity, both in the strength and direction of the observed effects. Climate was the most important driver for some species, while others responded more to connectivity, or simply to the presence of high quality substrates within the reserves. Species occurrences varied also across geographical regions, especially between the UK and the rest of Europe. Our results show that wood-inhabiting fungi in European beech forests respond individualistically to habitat filters and differ in their biogeographical distribution patterns, and they thus provide a detailed perspective of how wood-inhabiting fungal communities are structured across Europe.     

Isolation of wood-inhabiting fungi from Canadian hardwood logs

Wood-inhabiting fungi include many molds, wood-staining fungi, and decay fungi. Most of these fungal species can result in economic losses to wood users. Studies on molds, staining fungi, and decay fungi are necessary to be able to control their growth on wood and wood products. In this study, wood-inhabiting fungi were isolated from logs of 3 major Canadian hardwood species: sugar maple, white birch, and yellow birch. Two media were used for isolation. From these 3 wood species, a total of 1198 fungal cultures were obtained from summer- and winter-harvested logs in dry storage and under water sprinkling. The results showed that most fungal species were not host specific and affected all of the wood species tested. Frequently isolated molds were Alternaria alternata, Trichoderma species, and Mucor/Rhizopus (Zygomycota) species, frequently isolated staining fungi were Ophiostoma piceae and Ophiostoma piliferum, a frequently isolated bark saprophyte was Nectria cinnabarina, and frequently isolated decay fungi were taxa of the phylum Basidiomycota. More fungal species were isolated from summer-harvested logs than from winter-harvested logs. Fewer fungal cultures, especially decay fungi, were isolated from logs in early storage than from logs in late storage.     

Species diversity of polyporoid and corticioid fungi in northern hardwood forests with differing management histories

Effects of forest management on fungal diversity were investigated by sampling fruit bodies of polyporoid and corticioid fungi in forest stands that have different management histories. Fruit bodies were sampled in 15 northern hardwood stands in northern Wisconsin and the upper peninsula of Michigan. Sampling was conducted in five old-growth stands, five uneven-age stands, three even-age unthinned stands and two even-age thinned stands. Plots 100 m x 60 m were established and 3000 m2 within each plot was sampled during the summers of 1996 and 1997. A total of 255 polyporoid and corticioid morphological species were identified, 46 (18%) of which could not be assigned to a described species. Species accumulation curves for sites and management classes differed from straight lines, although variability from year to year suggests that more than 2 y of sampling are needed to characterize annual variation. Mean species richness and diversity index values did not vary significantly by management class, although mean richness on large diameter wood (> or = 15 cm diam) varied with moderate significance. Richness values on small diameter debris varied significantly by year, indicating that a large part of year-to-year variability in total species richness is due to small diameter debris. Ten species had abundance levels that varied by management class. Two of these species. Changes in the diversity and species composition of the wood-inhabiting fungal community could have significant implications for the diversity, health and productivity of forest ecosystems.     

Wood-inhabiting insects can function as targeted vectors for decomposer fungi

Most wood-inhabiting fungi are assumed to be dispersed primarily by wind, with the exception of a few species involved in mutualistic relationships with insects. In this study we tested whether several species of wood-inhabiting insects can function as dispersal vectors for non-mutualistic fungi, which would indicate that wood-inhabiting fungi can benefit from targeted animal-mediated dispersal. We sampled wood-inhabiting beetles (Coleoptera) from freshly felled wood experimentally added to forests and used DNA metabarcoding to investigate the fungal DNA carried by these insects. Staphylinid beetles rarely contained fungal DNA, while Endomychus coccineus, Glischrochilus hortensis and Glischrochilus quadripunctatus frequently carried fungal DNA with a composition specific to the insect taxon. A large proportion of the obtained fungal sequences (34%) represented decomposer fungi, including well-known wood-decay fungi such as Fomitopsis pinicola, Fomes fomentarius, Trichaptum abietinum and Trametes versicolor. Scanning electron microscopy further showed that some of the fungal material was carried as spores or yeast cells on the insect exoskeletons. Our results suggest that insect-vectored dispersal is of broader importance to wood-inhabiting fungi than previously assumed.     

Effects of Forest Use on Aphyllophoraceous Fungal Community Structure in Sarawak, Malaysia

Aphyllophoraceous fungi are expected to reflect changes in the environmental conditions caused by forest use. To reveal the effects of forest uses on the fungal community structure, we performed a 3‐month survey of aphyllophoraceous species in five forest types (undisturbed primary forest, isolated patches of primary forest, old and young fallow forest, and rubber plantations) in Sarawak, Malaysia in 2005. We used a canonical correspondence analysis (CCA) to reveal the relationships between fungal community composition and the environmental variables (canopy openness, soil water potential, amount and composition of coarse woody debris, litter mass, basal area, plant species composition). A total of 155 samples from 67 species were collected during the study period. The fungal species density represented by the number of species in a transect differed significantly among forest types. The fungal species density increased significantly with increasing number of pieces of coarse woody debris (CWD), but decreased significantly with increasing the scores of second axis of principal component analysis (PCA) for plant species composition. In the CCA ordination, automatic forward selection revealed that only the number of pieces of CWD significantly affected the fungal species composition. The occurrences of Flabellophora licmophora, Coriolopsis retropicta, Microporus vernicipes, and Amauroderma subrugosum were positively correlated with the number of pieces of CWD. Our study clearly demonstrated that forest use negatively affected aphyllophoraceous fungal diversity and suggest that the quantity of CWD would be an important determinant of fungal diversity and composition.     

Genetic diversity and population structure in urban white-tailed deer

Habitat fragmentation in urban areas has left many species isolated and vulnerable to loss of genetic variation. White-tailed deer (Odocoileus virginianus), however, thrive in urban areas. We compared genetic diversity and structure among deer in 2 urban metroparks with deer in a fenced reserve and with deer from an open, continuously distributed population to inform urban deer management. If urban deer maintain species' typical matrilineal genetic structure, removal of female groups may effectively reduce local abundance. However, if gene flow in urban areas is high, dispersal may impede efforts to reduce abundance. Although genetic diversity was high and mean relatedness was near zero in all locations, distributions of pairwise relatedness in urban metroparks and the fenced reserve contained greater proportions of closely and distantly related deer than the open locations, likely attributable to matrilineal structure. In addition, deer from the metroparks (approx. 65 km apart) were moderately differentiated (F_st = 0.092) indicating gene flow in urban areas may be less than in other landscapes. Our results indicate that removal of matrilineal groups may reduce local urban deer abundance without inducing immigration from surrounding areas. © The Wildlife Society, 2012     

Accumulation and decay dynamics of coarse woody debris in a Japanese old-growth subalpine coniferous forest

Far less is known about the coarse woody debris (CWD) stock and decay process in temperate Asia compared with that in boreal and temperate Europe and North America. We estimated coniferous CWD stock (logs and snags), decay rate and process, and fungal species responsible for the decay process in a Japanese subalpine coniferous forest. The CWD mass was 42.4 Mg ha^?1, which was the greatest among the previous data recorded in temperate Asia. The decay rate calculated using the annual input of CWD divided by CWD accumulation was 0.036 year^?1, whereas the decay rate when measured chronosequentially was 0.020–0.023 year^?1. The decay process was divided into two phases characterized by different dominant organic chemical constituents. In the first phase, both acid-unhydrolyzable residue and holocellulose decayed simultaneously, suggestive of the white-rot process. In the second phase, holocellulose was selectively decomposed and AUR accumulated, suggestive of the brown-rot process. Nutrients (N, P, K, Na, Mg, and Ca) were mineralized in the first phase but immobilized in the second phase. The fruiting bodies of 26 taxa of fungi were recorded as occurring on CWD in the study area. Trichaptum abietinum and T. fuscoviolaceum, which dominated in the first phase and are known as white-rot fungi, were assumed to be the main decomposers of lignocellulose in the first phase. Although no known strong wood decomposers dominated the second phase, Laetiporus sulphureus and Oligoporus caesius, known as brown-rot fungi, were expected to participate in the selective decomposition of holocellulose in the second phase.     

Influence of Forest Management on the Species Richness and Composition of Wood-inhabiting Basidiomycetes in Swiss Forests

In order to investigate the diversity of wood-inhabiting aphyllophoroid basidiomycetes in Swiss forests, 86 plots of 50 m ² were established. They harboured a total of 3339 samples of woody debris, classified according to three categories (coarse, fine, and very fine woody debris), yielding 238 species of wood-inhabiting fungi. The selected sites cover the main forest types of Switzerland and various degrees of management intensity. A multiple linear regression analysis showed that substrate variation, i.e. differences in the quality of dead wood, including volume, age, degree of decomposition and host tree species, are the most important factors influencing diversity of wood-inhabiting fungi. In addition, a Principle Coordinate Analysis highlighted differences in the fungal communities in the different forest types. The greatest fungal species richness is found on thermophilic deciduous tree and woody shrub species. Fine and very fine woody debris, even present in intensively managed forests, often serve as important refuges for many species. Forests with a recent management intervention were found to be either species poor or species rich. Possible reasons for these differences may lay in forest size and landscape fragmentation, the distance to the nearest species pool or microclimatic factors. In Switzerland intensively managed forests harbour significantly less wood-inhabiting, aphyllophoroid fungi than non-managed or extensively managed forests. This is the case in both deciduous forests and in conifer forests. However, occasionally intensively managed forest will also harbour rare and endangered species.     

原麝和林麝冬夏两季粪便真菌菌群多样性

肠道微生物群对宿主健康的影响取决于饮食环境和宿主等因素.本研究通过Illumina MiSeq平台对冬、夏两季林麝和原麝粪便真菌ITS1区段进行测序,探究原麝和林麝肠道真菌菌群结构特性及季节因素对其多样性的影响.结果 表明,林麝和原麝肠道真菌组成中子囊菌门Ascomycota均为优势菌门,它们的相对丰度随物种和季节因素...     

Taxonomic gap in wood-inhabiting fungi: identifying understudied groups by a systematic survey

Despite advances in phylogenetic research and the number of ecological studies focusing on wood-inhabiting fungi, these species still represent a taxonomically poorly known group of organisms. In this study, our overall aim was to detect and characterize the understudied wood-inhabiting fungal groups in the beech forests of Navarre (northern Spain). We present a list of 326 wood-inhabiting fungal species, out of which 36 % are first regional records. Comparing the already recorded fungal species in this territory and the list of firstly recorded species, we found that field-mycologists tend to focus on certain fungal groups, and in general rare species are less frequently encountered. Particularly, species with corticioid fruit body type have been especially overlooked in this territory. We attribute the high proportion of new regional records to the use of a systematic sampling design.     

Effects of red deer on tree regeneration and growth in Aorangi Forest, Wairarapa

New Zealand forests have been substantially modified by introduced red deer over the past century. New Zealand’s indigenous forest managers need to know if regeneration of palatable tree species can be restored following control or eradication of browsing ungulates. Aorangi Forest, Wairarapa, suffered dramatic changes in forest understorey composition by the 1950s after more than seven decades of colonisation by red deer (Cervus elaphus), feral goats (Capra hircus) and pigs (Sus scrofa). Since then feral goats have been eradicated, but red deer and pigs persist throughout Aorangi Forest despite ongoing recreational hunting. This study uses data from paired fenced and unfenced plots established at seven sites in Aorangi Forest between 1981 and 1987, and re-measured in 2004, to show the effects of ungulates on tree (≥ 2 cm diameter at breast height) regeneration and growth. Our results show that browsing by red deer has prevented regeneration of kanono (Coprosma grandifolia), a highly palatable, fast-growing sub-canopy hardwood tree. Deer reduced the growth of mahoe (Melicytus ramiflorus) trees, probably by directly browsing epicormic shoots. The regeneration of other less palatable sub-canopy trees (e.g. porokaiwhiri, Hedycarya arborea), and slower-growing canopy species (e.g. hinau, Elaeocarpus dentatus and rewarewa, Knightia excelsa) appears to have been unaffected by deer browsing. Accordingly, tree species composition does not appear to have been greatly affected by browsing from deer populations in Aorangi Forest over the past two decades.     

Impact of white-rot fungi on numbers and community composition of bacteria colonizing beech wood from forest soil

White-rot fungi are important wood-decomposing organisms in forest ecosystems. Their ability to colonize and decompose woody resources may be strongly influenced by wood-inhabiting bacteria that grow on easily utilizable compounds e.g. oligomers of wood-polymers released by fungal enzymes. However, so far, it is not known how white-rot fungi deal with the presence of potential competing bacteria. Here, the effects of two white-rot fungi, Hypholoma fasciculare and Resinicium bicolor, on the numbers and composition of bacteria colonizing sterile beech wood blocks from forest soil are reported. Both total numbers (microscopic counts) and the numbers of cultivable wood-inhabiting bacteria were considerably lower in wood blocks that became colonized by the white-rot fungi than in control blocks. This points to the fungi out-competing the opportunistic bacteria. The presence of white-rot fungi resulted in a change in the relative abundance of families of cultivable bacteria in wood and also in a change of denaturing gradient gel electrophoresis patterns of directly amplified 16S rRNA gene fragments. Analysis of the bacterial community structure in soil adhering to exploratory mycelium (cords) indicated that fungal species-specific effects on bacterial community composition were also apparent in this fungal growth phase.     

Detailed information on fruiting phenology provides new insights on wood-inhabiting fungal detection

Fruiting phenology traits may have a large effect on the detection of fungal species. Detailed studies considering these biologically important traits are, however, surprisingly scarce. We conducted a rigorous fruit body monitoring of wood-inhabiting fungal occurrences over one fruiting season. Taxon-specific longevity of the fruiting was different between different morphological groups. This was mainly due to agaric fruiting being shorter than other groups. Different number and timing of surveys are needed to detect the majority of the fruiting taxa of different wood-inhabiting fungal groups.     

Influence of the geographic distribution of prion protein gene sequence variation on patterns of chronic wasting disease spread in white-tailed deer (Odocoileus virginianus)

ABSTRACT

Managing and controlling the spread of diseases in wild animal populations is challenging, especially for social and mobile species. Effective management benefits from information about disease susceptibility, allowing limited resources to be focused on areas or populations with a higher risk of infection. Chronic wasting disease (CWD), a transmissible spongiform encephalopathy that affects cervids, was detected in Colorado in the late 1960s. CWD was detected in Illinois and Wisconsin in 2002 and has since spread through many counties. Specific nucleotide variations in the prion protein gene (PRNP) sequence have been associated with reduced susceptibility to CWD in white-tailed deer. Though genetic resistance is incomplete, the frequency of deer possessing these mutations in a population is an important factor in disease spread (i.e. herd immunity). In this study we sequenced 625 bp of the PRNP gene from a sampling of 2433 deer from Illinois and Wisconsin. In north-central Illinois where CWD was first detected, counties had a low frequency of protective haplotypes (frequency <0.20); whereas in northwestern Illinois counties, where CWD cases have only more recently been detected, the frequency of protective haplotypes (frequency >0.30) was much higher (p < 0.05). Protective haplotype frequencies varied significantly among infected and uninfected geographic areas. The frequency of protective PRNP haplotypes may contribute to population level susceptibility and may shape the way CWD has spread through Illinois. Analysis of PRNP haplotype distribution could be a useful tool to assess CWD risk and allocate resources to contain and reduce the spread of infection.     

Individual and interactive effects of Amur honeysuckle (Lonicera maackii) and white-tailed deer (Odocoileus virginianus) on herbs in a deciduous forest in the eastern United States

Invasive Amur honeysuckle (Lonicera maackii) has reduced diversity, growth, and reproduction of native herbs in the Midwest USA. These effects may be compounded by browsing from overabundant white-tailed deer (Odocoileus virginianus). We used experimental treatments of honeysuckle (present, absent, removed) and deer (present, excluded) to measure their independent and interactive impacts on diversity, richness, and abundance of herbs in a deciduous forest in southwestern Ohio, USA. Species diversity and richness of herbs were not affected by honeysuckle or deer. Honeysuckle reduced abundance of annuals, graminoids, spring perennials, and summer perennials; deer decreased abundance of annuals and spring perennials, but increased abundance of graminoids. A deer × honeysuckle interaction showed that when honeysuckle was absent or removed, browsing by deer kept abundance of annuals and spring perennials low. Effects of honeysuckle and deer also were assessed for the three most abundant herbs: honeysuckle reduced abundance of Carex rosea and Sanicula odorata, and deer reduced abundance of Viola soraria. Herb abundance varied seasonally and annually. Honeysuckle and deer reduced number of leaves/stem of Maianthemum racemosum and a deer × honeysuckle interaction indicated that the negative effect of honeysuckle was released only when deer were excluded. Herb abundance and M. racemosum rebounded to or near to control levels after removal of honeysuckle. Our findings revealed that impacts of invasive honeysuckle or overabundant deer were not the same across all levels of biological organization (i.e., individual species, growth forms, community measures of species diversity/richness). Measuring impacts of these species at multiple levels of biological organization, considering deer × honeysuckle interactions, and collecting data for several years to account for seasonal and annual fluctuations will help guide management plans. The rapid response by herbs to removal of honeysuckle demonstrated the resilience of this community and is a hopeful sign for restoration of native understory herbs.     

Restoration of three forest herbs in the Liliaceae family by manipulating deer herbivory and overstorey and understorey vegetation

Background: Research on herbaceous vegetation restoration in forests characterised by overstorey tree harvests, excessive deer herbivory, and a dominant fern understorey is lacking. Most of the plant diversity found in Eastern hardwood forests in the United States is found in the herbaceous understorey layer. Loss of forest herbaceous species is an indicator of declining forest conditions.

Aims: The combined effects of deer herbivory, competitive understorey vegetation removal, and overstorey tree removal on the abundance and reproductive capacity of three understorey herbs in the Liliaceae family were evaluated.

Methods: A split-plot randomised block design was used with three replicates. Treatments included three harvest intensities, fenced/unfenced, herbicide/no herbicide-treated, prescribed burn/no prescribed burn, and all combinations. A generalised linear model was used to compare treatment effects over 8 years.

Results: Both fruit production and cover increased significantly in fenced areas for all three species. There was a significant 6-year recovery period for cover of the three species in response to herbicide. There was a significant 4-year recovery period of fire-treated plots for fruit production of the three species. The most intensively cut, fenced, and herbicide-treated plots had the greatest increases in sapling and Rubus spp. cover. Cover and fruit production of the three herbs were significantly greatest in the moderate-cut treatment.

Conclusions: Restoration of these three liliaceous species is most likely to occur in Eastern deciduous forests and similar forests using a combined fenced and moderate-cut treatment.     

古田山国家级自然保护区木腐真菌物种多样性及分布

木腐真菌是微生物的一个重要类群, 主要以倒木为生长基质, 通过产生各种水解酶将倒木的纤维素、木质素和半纤维素分解为小分子物质, 对促进森林生态系统中的营养物质循环发挥着重要的生态功能。于2016年8月在浙江古田山国家级自然保护区开展的木腐真菌野外调查, 利用形态学和DNA序列分析对采集的标本进行了物种鉴定, 并分析了木腐真菌的物种组成和地理成分。在采集的158份标本中鉴定木腐真菌45属92种, 其中白腐真菌78种, 褐腐真菌14种。古田山的木腐真菌物种区系组成中, 热带-亚热带成分比例最高。在158份木腐真菌标本中, 97份标本采自直径大于10 cm的倒木或树桩上, 分属于76个种, 是木腐真菌生长的主要基质大小类型; 48份标本采自直径为2-10 cm的枝干上, 分属38个种; 13份标本采自直径小于2 cm的枝干上, 分属12种。不同腐烂等级倒木上生长的真菌数量和种类差异明显, 其中一级腐烂倒木上采集到9份标本(7种), 二级腐烂倒木上采集到86份标本(45种), 三级腐烂倒木上49份标本(29种), 四级腐烂倒木上14份标本(14种)。结果表明, 林分中倒木直径大小和腐烂程度是影响木腐真菌生长与分布的重要因子。