Belowground ectomycorrhizal communities in three Norway spruce stands with different degrees of decline in the Czech Republic

Diversity and distribution of tropical ectomycorrhizal fungi

The tropics were long considered to have few ectomycorrhizal fungi, presumably due to a paucity of ectomycorrhizal host plants relative to higher-latitude ecosystems. However, an increase in research in tropical regions over the past 30 years has greatly expanded knowledge about the occurrence of tropical ectomycorrhizal fungi. To assess their broad biogeographic and diversity patterns, we conducted a comprehensive review and quantitative data analysis of 49 studies with 80 individual data sets along with additional data from GlobalFungi to elucidate tropical diversity patterns and biogeography of ectomycorrhizal fungi across the four main tropical regions: the Afrotropics, the Neotropics, Southeast Asia, and Oceania. Generalized linear models were used to explore biotic and abiotic influences on the relative abundance of the 10 most frequently occurring lineages. We also reviewed the available literature and synthesized current knowledge about responses of fungi to anthropogenic disturbances, and their conservation status and threats. We found that /russula-lactarius and /tomentella-thelephora were the most abundant lineages in the Afrotropics, the Neotropics, and Southeast Asia, whereas /cortinarius was the most abundant lineage in Oceania, and that /russula-lactarius, /inocybe, and /tomentella-thelephora were the most species-rich lineages across all of the tropical regions. Based on these analyses, we highlight knowledge gaps for each tropical region. Increased sampling of tropical regions, collaborative efforts, and use of molecular methodologies are needed for a more comprehensive view of the ecology and diversity of tropical ectomycorrhizal fungi.

Environmental Effects among Differently Located and Fertile Sites on Forest Basal-Area Increment in Temperate Zone

Environmental properties differently influence the growth of forest tree species. The antagonistic effects of variable environmental properties classify the forest response according to various tree compositions among different sites. The division of the forest response was assessed in 52 stands arranged into 26 types of 13 site management populations (MPs) in 5 areas in the Czech Republic territory. The assessment was performed using time-series multiple regressions of basal-area increment from pure immature stands of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), oaks (Quercus sp.), ash (Fraxinus excelsior) and willows (Salix sp.) dependent on the interpolated average temperatures, annual precipitation, atmospheric concentrations of SO2, NOx and O3 and soil properties over the period 1971–2008 at p < 0.05. Site MPs differentiated the forest response to a greater extent than tree species. The response of the forests was significantly distributed by means of the montane, upland and waterlogged sites. The multiple determination index (r2) ≥ 0.6 indicated an adaptable tree increment but an interval of r2 between 0.80–0.92 implied forest sensitivity to variability in environmental properties on non-waterlogged sites. The index r2 < 0.6 suggested a fluctuating forest increment that reflects environmental variability inconsistently. The fluctuating increment most affected the spruce and pine stands grown from upland to submontane locations. Montane spruce stands, as well as rock pines, appeared to be one of the most sensitive ones to environmental change. Floodplain forests seemed as adaptable to variable environmental properties.

Multigene phylogeny and taxonomic revision of Atheliales s.l.: Reinstatement of three families and one new family, Lobuliciaceae fam. nov

Atheliales (Agaricomycetes, Basidiomycota) is an order mostly composed of corticioid fungi, containing roughly 100 described species in 20 genera. Members exhibit remarkable ecological diversity, including saprotrophs, ectomycorrhizal symbionts, facultative parasites of plants or lichens, and symbionts of termites. Ectomycorrhizal members are well known because they often form a major part of boreal and temperate fungal communities. However, Atheliales is generally understudied, and molecular data are scarce. Furthermore, the order is riddled with many taxonomic problems; some genera are non-monophyletic and several species have been shown to be more closely related to other orders. We investigated the phylogenetic position of genera that are currently listed in Atheliales sensu lato by employing an Agaricomycetes-wide dataset with emphasis on Atheliales including the type species of genera therein. A phylogenetic analysis based on 5.8S, LSU, rpb2, and tef1 (excluding third codon) retrieved Atheliales in subclass Agaricomycetidae, as sister to Lepidostromatales. In addition, a number of Atheliales genera were retrieved in other orders with strong support: Byssoporia in Russulales, Digitatispora in Agaricales, Hypochnella in Polyporales, Lyoathelia in Hymenochaetales, and Pteridomyces in Trechisporales. Based on this result, we assembled another dataset focusing on the clade with Atheliales sensu stricto and representatives from Lepidostromatales and Boletales as outgroups, based on ITS (ITS1-5.8S-ITS2), LSU, rpb2, and tef1. The reconstructed phylogeny of Atheliales returned five distinct lineages, which we propose here as families. Lobulicium, a monotypic genus with a distinct morphology of seven-lobed basidiospores, was placed as sister to the rest of Atheliales. A new family is proposed to accommodate this genus, Lobuliciaceae fam. nov. The remaining four lineages can be named following the family-level classification by Jülich (1982), and thus we opted to use the names Atheliaceae, Byssocorticiaceae, Pilodermataceae, and Tylosporaceae, albeit with amended circumscriptions.

Chemical characterization of mountain forest soils: impact of long-term atmospheric deposition loadings (Czech-Polish-German border region)

The composition of lipids in soil offers clues to soil degradation processes due their persistency and selectivity in soil, and close relation to long-term processes in the ecosystem, thanks to their role in cell membranes of organisms. Organic solvent-extractable compounds were recovered from soils collected at two sites differing in the degree of forest damage. Gas chromatography/mass spectroscopy and Fourier transform infrared spectroscopy were applied in order to characterize solvent-extractable lipids. Raman spectroscopy was also applied as it provides distinct advantages for determining the structural order of carbonaceous materials. The organic matter measurement techniques were combined with an established simultaneous multi-element measurement technique. Variations in individual soil horizons from the sites were reflected in the crystallinity of epicuticular waxes, presence of long-chain aliphatic hydrocarbons, concentrations of n-alkanes, saturated and unsaturated fatty acids, dicarboxylic acids, and in the content of aromatic structures, hydroxyl, ester, and carboxylic acid groups. The results are explained by differently transformed organic matter. The concentrations of elements in the soils were also affected by atmospheric depositions, including higher accumulations of arsenic and antimony, and lower contents of natural nutrients. These data have potential to be used as sensitive biogenic indicators of ecosystem damage by long-term atmospheric depositions.

Ectomycorrhizal Community on Norway Spruce Seedlings Following Bark Beetle Infestation

Ectomycorrhizal (ECM) fungi importantly influence seedling growth, nutrition, and survival and create an extensive mycelial network interconnecting tree species and enabling resource redistribution. Due to their symbiotic relationship with trees, they are impacted by forest disturbances, which are of increasing relevance due to climate change. The effect of disturbance on seedling colonization and their morphology is still largely unknown. Seedling growth parameters and the ECM fungal assemblage on the roots of Norway spruce (Picea abies (L.) H. Karst.) seedlings were assessed in mature spruce forests attacked and destroyed by bark beetle and in a mature non-attacked forest as a reference. We did not detect significant differences in number of ECM species on seedling roots among forest types, but ECM species composition changed; Tylospora fibrillosa (Burt) Donk, Meliniomyces variabilis Hambl. & Sigler, and Phialocephala fortinii C.J.K. Wang & H.E. Wilcox were characteristic species in the forest destroyed by bark beetle, whereas Lactarius, Cortinarius, and Russula were in the mature forest. Forest type further significantly influenced the height, root length, and root collar thickness of seedlings and the proportion of exploration types of mycorrhizae.

Pollution control enhanced spruce growth in the "Black Triangle" near the Czech-Polish border

Norway spruce (Picea abies (L.) Karst.) stands in certain areas of Central Europe have experienced substantial dieback since the 1970s. Understanding the reasons for this decline and reexamining the response of forests to acid deposition reduction remains challenging because of a lack of long and well-replicated tree-ring width chronologies. Here, spruce from a subalpine area heavily affected by acid deposition (from both sulfur and nitrogen compounds) is evaluated. Tree-ring width measurements from 98 trees between 1000 and 1350m above sea level (a.s.l.) reflected significant May-July temperature signals. Since the 1970s, acid deposition has reduced the growth-climate relationship. Efficient pollution control together with a warmer but not drier climate most likely caused the increased growth of spruce stands in this region, the so-called "Black Triangle," in the 1990s.

Studies on the ectomycorrhizal community in a declining Quercus suber L. stand

This survey was carried out in a Quercus suber L. stand with many trees affected by the disease "oak decline". Its aim was to obtain information about both the belowground ectomycorrhizal fungal community in a declining Q. suber stand as a whole, and the ectomycorrhizal fungal community of individual tree (EFT) detected in healthy and diseased plants. To this end, we first categorized the trees into four different decline classes (one for healthy plants and three for diseased plants) and then, by using morphological and molecular tools, we identified the ectomycorrhizas isolated from samples collected near the trees with different declining classes. The ectomycorrhizal community as a whole was seen to be composed of numerous ectomycorrhizal fungal species, only some of which appeared to be dominant (Cenococcum geophilum, Lactarius chrysorrheus, and some species of Tomentella genus), while most occurred sporadically. Results show that all root tips observed are mycorrhized and that decline class does not influence the number of ectomycorrhizal root tips found in the EFTs, thus oak decline does not impact the investment in ectomycorrhizal symbiosis. However, some statistical differences can be observed in the values of evenness and taxonomic distinctness in the EFT associated with trees with different states of health. Finally, both the analysis of similarity test and the ordination technique highlight a compositional difference between the EFT associated with trees in different health conditions, but also suggest that other factors may play a role in causing these differences.

Seedling mycorrhizal type and soil chemistry are related to canopy condition of Eucalyptus gomphocephala

The health of Eucalyptus gomphocephala is declining within its natural range in south-western Australia. In a pilot study to assess whether changes in mycorrhizal fungi and soil chemistry might be associated with E. gomphocephala decline, we set up a containerized bioassay experiment with E. gomphocephala as the trap plant using intact soil cores collected from 12 sites with E. gomphocephala canopy condition ranging from healthy to declining. Adjacent soil samples were collected for chemical analysis. The type of mycorrhiza (arbuscular or ectomycorrhizal) formed in containerized seedlings predicted the canopy condition of E. gomphocephala at the sites where the cores were taken. Ectomycorrhizal fungi colonization was higher in seedling roots in soil taken from sites with healthy canopies, whereas colonization by arbuscular mycorrhizal fungi dominated in roots in soil taken from sites with declining canopies. Furthermore, several soil chemical properties predicted canopy condition and the type of mycorrhizal fungi colonizing roots. These preliminary findings suggest that large-scale studies should be undertaken in the field to quantify those ectomycorrhiza (ECM) fungi sensitive to E. gomphocephala canopy decline and whether particular ECM fungi are bioindicators of ecosystem health.

Ectomycorrhizal fungal communities on seedlings and conspecific trees of Pinus mugo grown on the coastal dunes of the Curonian Spit in Lithuania

Ectomycorrhizal (ECM) communities of mature trees and regenerating seedlings of a non-native tree species Pinus mugo grown in a harsh environment of the coastal region of the Curonian Spit National Park in Lithuania were assessed. We established three study sites (S1, S2, and S3) that were separated from each other by 15 km. The ECM species richness was rather low in particular for mature, 100-year-old trees: 12 ectomycorrhizal taxa were identified by molecular analysis from 11 distinguished morphotypes. All 12 taxa were present on seedlings and on mature trees, with between 8-11 and 9-11 taxa present on seedlings and mature trees, respectively. Cenococcum geophilum dominated all ECM communities, but the relative abundance of C. geophilum mycorrhizas was nearly two times higher on seedlings than on mature trees. Mycorrhizal associations formed by Wilcoxina sp., Lactarius rufus, and Russula paludosa were also abundant. Several fungal taxa were only occasionally detected, including Cortinarius sp., Cortinarius obtusus, Cortinarius croceus, and Meliniomyces sp. Shannon's diversity indices for the ECM assemblages of P. mugo ranged from 0.98 to 1.09 for seedling and from 1.05 to 1.31 for mature trees. According to analysis of similarity, the mycorrhizal communities were similar between the sites (R = 0.085; P = 0.06) and only slightly separated between seedlings and mature trees (R = 0.24; P < 0.0001). An incidental fruiting body survey that was conducted weakly reflected the below-ground assessment of the ECM fungal community and once again showed that ECM and fruiting body studies commonly supply different partial accounts of the true ECM fungal diversity. Our results show that P. mugo has moved into quite distinct habitats and is able to adapt a suite of ECM symbionts that sufficiently support growth and development of this tree and allow for natural seedling regeneration.

Culturable bacterial populations associated with ectomycorrhizae of Norway spruce stands with different degrees of decline in the Czech Republic

The aim of this study was to determine which species of culturable bacteria are associated with ectomycorrhizae (ECM) of Norway spruce (Picea abies (L.) Karst) in the Sudety Mountains, exposed for years to atmospheric pollutants, acid rain, and climatic stress, and to identify particular species that have adapted to those conditions. Biolog identification was performed on bacterial species from ECM of adult spruce trees and seedlings of stands with low, intermediate, and high forest decline. Bacterial diversity in ECM associated with adult spruce trees, seedlings, and seedlings grown on monoliths was calculated; although the expected values appeared to vary widely, no significant differences among sites were observed. Dendrograms based on the identified bacterial species showed that stands with low forest decline clustered separately from the others. Principal component analysis of the normalized data for ECM-associated species showed a clear separation between stands with high forest decline and stands with low forest decline for seedlings and a less evident separation for adult spruce trees. In conclusion, shifts in ECM-associated culturable bacterial populations seem to be associated with forest decline in Norway spruce stands. Some bacterial species were preferentially associated with mycorrhizal roots depending on the degree of forest decline; this was more evident in seedlings where the species Burkholderia cepacia and Pseudomonas fluorescens were associated with, respectively, ECM of the most damaged stands and those with low forest decline.

Establishment of ectomycorrhizal fungal community on isolated Nothofagus cunninghamii seedlings regenerating on dead wood in Australian wet temperate forests: does fruit-body type matter?

Decaying wood provides an important habitat for animals and forms a seed bed for many shade-intolerant, small-seeded plants, particularly Nothofagus. Using morphotyping and rDNA sequence analysis, we compared the ectomycorrhizal fungal community of isolated N. cunninghamii seedlings regenerating in decayed wood against that of mature tree roots in the forest floor soil. The /cortinarius, /russula-lactarius, and /laccaria were the most species-rich and abundant lineages in forest floor soil in Australian sites at Yarra, Victoria and Warra, Tasmania. On root tips of seedlings in dead wood, a subset of the forest floor taxa were prevalent among them species of /laccaria, /tomentella-thelephora, and /descolea, but other forest floor dominants were rare. Statistical analyses suggested that the fungal community differs between forest floor soil and dead wood at the level of both species and phylogenetic lineage. The fungal species colonizing isolated seedlings on decayed wood in austral forests were taxonomically dissimilar to the species dominating in similar habitats in Europe. We conclude that formation of a resupinate fruit body type on the underside of decayed wood is not necessarily related to preferential root colonization in decayed wood. Rather, biogeographic factors as well as differential dispersal and competitive abilities of fungal taxa are likely to play a key role in structuring the ectomycorrhizal fungal community on isolated seedlings in decaying wood.