Welcome to IMC 2018 International Mycological Congress
Conference Calendar
Macroecology analyses of millions of fruit body records: Environmental drivers of phenology and species assemblies across Europe
- C. Andrew
- E. Heegaard
- R. Halvorsen
- T. Kuyper
- J. Heilmann-Clausen
- I. Krisai-Greilhuber
- C. Bässler
- S. Egli
- A. Gange
- K. Høiland
- P. Kirk
- B. Senn-Irlet
- L. Boddy
- U. Büntgen
- H. Kauserud
Abstract
Abstract
Fungal species occurrence observations are increasingly available for scientific analyses through citizen science projects and the digitization of museum records, rendering new and large-scale ecological resources. When combined with open-source data, there is unparalleled potential for addressing new questions in fields such as fungal ecology, biogeography, macroecology and global change biology. We have assembled a pan-European mycological meta-database (ClimFun) that has been integrated with open-source environmental and species traits data. Initially 7.3 million unique fungal species fruit body records, spanning nine countries, were processed and assembled into 6 million records of more than 10,000 fruiting species. We will here present results from two studies where we utilize the data. In the first, we assess the phenology of fungal fruiting at a European scale and relates the phenology to climate variability and the seasonality of fungal fruiting. Mean annual temperature is ubiquitously important, and more so for autumnal fruiting fungi. Spring fruiting fungi, especially ectomycorrhizal fungi, are additionally responsive to primary productivity. There is significant likelihood that further climatic change, especially in temperature, will impact fungal fruiting patterns at large spatial scales. In a second study we identify the major geographical and environmental gradients structuring fungal assemblages throughout Europe for two main nutritional modes, saprotrophic and ectomycorrhizal fungi. For both nutritional modes, mean annual temperature correlated most with the first gradient identified that structured assemblages. Soil organic carbon was the highest correlate of the second compositional gradient for ectomycorrhizal fungi, likely an indicator of vegetative- and pH-related covariance. In contrast, a pollution gradient was of secondary importance for saprotrophic fungi, reflected in a high correlation with nitrogen deposition. The highest rates of compositional change in fungal assemblages by time (1970–1990 versus 1991–2010) suggest targeting higher latitudes and altitudes for a better understanding of fungal dynamics related to climate change. We suggest further examination of the ranges and dispersal abilities of fungi to assess responses to global change and to aid fungal conservation.
Carbon and nitrogen metabolism gene frequencies across fungal functional groups and implications for ecosystem ecology
- A. Romero-Olivares
- A. Pringle
- N. Duncritts
- S. Frey
Fungal community dynamics following bark beetle infestation in Wyoming coniferous forests
- L. Van Diepen
Abstract
Abstract
Bark beetle (Dendroctonus spp.) outbreaks have impacted large areas in the Western United States in the past decade, resulting in large-scale conifer forest mortality. In these regions, the presence of bark beetles changed from endemic to epidemic levels because of increased mean winter temperatures and changes in precipitation patterns caused by climate change. Upon tree death, there is a change in plant-derived inputs via a large one-time needle drop and reduced root inputs, resulting in altered soil conditions. To understand how bark beetle induced changes in plant-derived inputs affect soil fungal community dynamics and associated biogeochemical cycling, a study was conducted in bark beetle affected coniferous forests in Southeastern Wyoming. Soil samples from healthy tree clusters were compared with infested and dead tree clusters. Impacts on fungal community dynamics were determined by measuring extracellular enzyme activities and sequencing the fungal community. Our study demonstrated increased extracellular enzymatic activity and turnover of the fungal community in dead compared with live stands. Specifically, lignin degrading enzyme activities were increased in infested tree clusters, while (hemi)cellulose degrading enzymes were only increased in the dead clusters compared to the healthy tree clusters. Furthermore, dead stands had lower proportional abundances of ectomycorrhizal fungi (ECM) as well as a relative increase in saprotrophic taxa compared to the healthy clusters. Taken together, our findings indicate significant changes in the structural and functional dynamics of the soil fungal community, which is correlated with changes in overall biogeochemical cycling, and could have large impacts on forest regeneration following large-scale disturbances caused by climate change.
Mycorrhizal fungal necromass decomposition under altered environmental conditions
- P. Kennedy
- C. Fernandez
- S. Mundra
- L. Morgado
- K. Heckman
- H. Kauserud
Abstract
Abstract
More carbon (C) is stored globally in soils than in the biotic and atmospheric pools combined. Given the large fluxes of C entering the soil through fungal necromass (i.e. dead biomass) and their substantial contribution to soil organic matter, understanding the decomposition dynamics of these fungal inputs represents a critical gap in our current knowledge of global climate change. With regard to intrinsic factors, it is now well recognized that, like plant materials, the biochemical composition of fungal hyphae is a very strong predictor of mass loss. Compared to the decomposition of plant materials, however, the effect of extrinsic (i.e. environmental conditions) factors on fungal necromass decomposition remains poorly characterized. In this presentation, we will present the results of our incubation of four different types of mycorrhizal fungal necromass in the SPRUCE warming experiment in a boreal peatland in Minnesota, USA. Over the past two years, we have characterized rates of mass loss of each necromass type, the microbial decomposer community present on the different types of necromass as well as the chemical composition of their remaining residues. Collectively, this work provides fundamental new insights about the dynamics of fungal necromass decomposition and its role in soil C sequestration under altered environmental conditions.
Tipping-point in C storage related to mode of N cycling across the arctic tundra-to-forest transition
- K. Clemmensen
- A. Michelsen
- S. Hallin
- R. Finlay
- B. Lindahl
Abstract
Abstract
Shrubs and trees are currently increasing in tundra areas across the Arctic, a response linked to recent climate warming. Ecotones between forests, dominated by ectomycorrhizal trees, and heathlands, dominated by ericoid mycorrhizal dwarf shrubs, are naturally found in transitions towards arctic and alpine zones, and may be used as space-for-time substitution to reflect long-term consequences of arctic greening on ecosystem level processes such as nitrogen (N) circulation and carbon (C) sequestration. Here, we present results from a subarctic-to-alpine ecotone from mountain birch forest to heath tundra in northern Sweden. We aimed to test the hypothesis that increasing abundance and activity of ectomycorrhizal fungi with increasing shrubs and trees would lead to faster N cycling through soil pools, and consequently lower C sequestration. We found a strong positive coupling between tree abundance and ectomycorrhizal fungal growth, both of which were negatively coupled with C sequestration. By DNA-barcode sequencing, we identified a shift in dominance from root-associated ascomycetes (mostly ericoid mycorrhizal) in the heath to cord-forming ectomycorrhizal fungi (mostly Cortinarius and Leccinum spp.) in the forest. Higher C/N-ratios, lower inorganic N levels and lower abundance of functional genes reflecting inorganic N cycling in the forest suggested prevalence of organic N cycling by ectomycorrhizal fungi here. We also transplanted organic substrates between forest and heath to investigate the decomposition capacity of microbial communities. Heath humus decomposed faster than forest humus, irrespective of incubation site, suggesting that the large carbon sink in the heath was not driven by low quality of the organic matter. Furthermore, when tree roots and ectomycorrhizal fungi – but not ericoid roots and associated fungi – were excluded, incubated sample mass increased, suggesting sustained belowground input, but decreased decomposition rate. Taken together our data suggest that the lower C sequestration rate in forest despite the larger litter inputs here is a consequence of more efficient ectomycorrhizal nutrient mining from organic pools and associated soil C loss. In contrast, when stress-tolerant ericoid mycorrhizal plants and fungi, as in heaths, dominate soil processes, decomposition is slower and more, relatively good quality organic matter accumulates. Our results support the idea that the presence and relative decomposition capacity of mycorrhizal fungi, rather than different litter input quantities or qualities, determine long-term carbon sink strength across northern ecosystems. Such direct coupling between tree production and humus decomposition via mycorrhizal fungal communities is important to include in models predicting future C balance of the region, as the globally important soil C stocks may amplify atmospheric warming potential considerably if released through decomposition.
Fungal community shifts along a fire severity gradient in a Boreal forest
- L. Pérez Izquierdo
- K. Clemmensen
- B. Lindahl
Abstract
Abstract
Boreal forest soils store a major fraction of the global terrestrial carbon. However, fires are pervasive disturbances that may critically trigger the carbon loss from these forest soils and in turn, influence the soil microbial communities with important outcomes over carbon dynamics of northern ecosystems. Here, we assessed the fire impacts on fungal communities, fungal transformations of organic matter and soil nutrients on an ecological gradient in fire severity. The study is part of a larger collaborative venture to investigate ecosystem recovery after the Västmanland fire in 2014, the largest Swedish forest fire in modern times. We sampled 25 and 7 plots stablished in burned (differing in fire severity damage) and un-burned areas respectively. Subplots subjected to logging and non-logging treatments were in turn established in each burned plot. As expected, the fire greatly affected the fungal community composition, with a negative effect on fungal biomass. On the other hand, the tree logging after the fire reduced the pine root biomass affecting the fungal community structure but not the fungal biomass. Our preliminary results suggest that the survival of Pinus sylvestris root biomass, indicative of fire severity, is one the major drivers of fungal communities, especially for ectomycorrhizal fungi and those from the group Leotiomycetes and Saccharomycetes. Gaining knowledge about post-fire ecosystem processes and fungal dynamics will contribute to a better understanding of fire ecology and succession of Boreal forests.