Dramatic changes in ectomycorrhizal community composition, root tip abundance and mycelial production along a stand‐scale nitrogen deposition gradient

Kjøller, Rasmus; Nilsson, Lars Ola; Hansen, Karin; Schmidt, Inger Kappel; Vesterdal, Lars; Gundersen, Per

doi:10.1111/j.1469-8137.2011.04041.x

Cited by 163 publications

(122 citation statements)

References 46 publications

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“…Another key driver of EMF community composition is nitrogen (NO 3 À , NH 4 þ ) availability, as shown in temperate and boreal forests (e.g., Toljander et al 2006, Kjoller et al 2012 as well as in bacterial and fungal communities in Antarctic soils (Yergeau et al 2007). Nitrate and NH 4 þ increased from subzone A to D and were correlated with EMF community structure, extending the patterns seen in previous studies in the Arctic.…”

Section: Factors Shaping Emf Communitiesmentioning

confidence: 99%

Distribution and drivers of ectomycorrhizal fungal communities across the North American Arctic

Timling

Dahlberg²,

Walker

et al. 2012

Ecosphere

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Abstract. Ectomycorrhizal fungi (EMF) form symbioses with a few plant species that comprise a large fraction of the arctic vegetation. Despite their importance, the identity, abundance and distribution of EMF in the Arctic, as well as the key drivers controlling their community composition are poorly understood. In this study, we investigated the diversity and structure of EMF communities across a bioclimatic gradient spanning much of the North American Arctic. We collected roots from two principal arctic ectomycorrhizal host plants, Salix arctica and Dryas integrifolia, typically growing intermingled, at 23 locations stratified across the five bioclimatic subzones of the Arctic. DNA was extracted from ectomycorrhizal root tips and the ITS region was sequenced and phylogenetically analyzed. A total of 242 fungal Operational Taxonomic Units (OTUs) were documented, with 203 OTUs belonging to the Basidiomycota and 39 to the Ascomycota, exceeding the number of previously morphologically described EMF in the Arctic. EMF communities were dominated by a few common and species-rich families such as Thelephoraceae, Inocybaceae, Sebacinaceae, Cortinariaceae, and Pyronemataceae. Both host plants showed similar species richness, with 176 OTUs on Salix arctica and 154 OTUs on Dryas integrifolia. Host plant identity did not affect EMF community composition. The ten most abundant OTUs had a wide geographic distribution throughout the Arctic, and were also found in boreal, temperate and Mediterranean regions, where they were associated with a variety of hosts. Species richness did not decline with increasing latitude. However, EMF community structure changed gradually across the bioclimatic gradient with the greatest similarity between neighboring bioclimatic subzones and locations. EMF community structure was correlated with environmental factors at a regional scale, corresponding to a complex of glaciation history, geology, soil properties, plant productivity and climate. This is the first large-scale study of EMF communities across all five bioclimatic subzones of the North American Arctic, accompanied by an extensive set of environmental factors analyzed to date. While our study provides baseline data to assess shifts of plant and fungi distribution in response to climate change, it also suggests that with ongoing climate warming, EMF community composition may be affected by northward shifts of some taxa.

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Section: Factors Shaping Emf Communitiesmentioning

confidence: 99%

Distribution and drivers of ectomycorrhizal fungal communities across the North American Arctic

Timling

Dahlberg²,

Walker

et al. 2012

Ecosphere

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“…Furthermore, both fine-root architectural and morphological traits may vary as a consequence of interactions with soil biota, such as ectomycorrhizal fungi, which may confound plastic root responses to resource availability (Freschet et al 2015). On poor soils for example, ectomycorrhizal mycelium biomass increases (Nilsson et al 2005;Kjøller et al 2012;Bahr et al 2013), which enlarges the soil volume available to the plant (Smith and Read 2008), and therefore possibly reduces the need for fine-root architectural or morphological adjustments.…”

Section: Introductionmentioning

confidence: 99%

Fine-root trait plasticity of beech (Fagus sylvatica) and spruce (Picea abies) forests on two contrasting soils

et al. 2016

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Aim The fine roots of trees may show plastic responses to their resource environment. Several, contrasting hypotheses exist on this plasticity, but empirical evidence for these hypotheses is scattered. This study aims to enhance our understanding of tree root plasticity by examining intra-specific variation in fine-root mass and morphology, fine-root growth and decomposition, and associated mycorrhizal interactions in beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.) forests on soils that differ in resource availability. MethodsWe measured the mass and morphological traits of fine roots (i.e. ≤ 2 mm diameter) sampled to 50 cm depth. Fine-root growth was measured with ingrowth cores, and fine-root decomposition with litter bags. Mycorrhizal fungal biomass was determined using ingrowth mesh bags. Results Both tree species showed more than three times higher fine-root mass, and a ten-fold higher fine-root growth rate on sand than on clay, but no or marginal differences in overall fine-root morphology. Within the fine-root category however, beech stands had relatively more root length of their finest roots on clay than on sand. In the spruce stands, ectomycorrhizal mycelium biomass was larger on sand than on clay. Conclusions In temperate beech and spruce forests, fine-root mass and mycorrhizal fungal biomass, rather than fine-root morphology, are changed to ensure uptake under different soil resource conditions. Yet enhancing our mechanistic understanding of fine-root trait plasticity and how it affects tree growth requires more attention to fine-root dynamics, the functional diversity within the fine-roots, and mycorrhizal symbiosis as an important belowground uptake strategy.

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“…Ectomycorrhizal communities are usually composed of a diverse flora consisting of several dominant and many infrequent EMF species (Buée et al, 2007;Courty et al, 2010;Pena et al, 2010;Tedersoo et al, 2012a;Danielsen et al, 2013). EMF community structures are strongly influenced by N deposition (Lilleskov et al, 2011;Kjøller et al, 2012). Stable isotope studies have revealed that EMF species differ in their abilities to exploit different N sources (Hobbie and Hö gberg, 2012).…”

Section: Introductionmentioning

confidence: 99%

Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress

Pena

Polle

2013

The ISME Journal

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Mycorrhizal fungi have a key role in nitrogen (N) cycling, particularly in boreal and temperate ecosystems. However, the significance of ectomycorrhizal fungal (EMF) diversity for this important ecosystem function is unknown. Here, EMF taxon-specific N uptake was analyzed via 15 N isotope enrichment in complex root-associated assemblages and non-mycorrhizal root tips in controlled experiments. Specific 15 N enrichment in ectomycorrhizas, which represents the N influx and export, as well as the exchange of 15 N with the N pool of the root tip, was dependent on the fungal identity. Light or water deprivation revealed interspecific response diversity for N uptake. Partial taxonspecific N fluxes for ectomycorrhizas were assessed, and the benefits of EMF assemblages for plant N nutrition were estimated. We demonstrated that ectomycorrhizal assemblages provide advantages for inorganic N uptake compared with non-mycorrhizal roots under environmental constraints but not for unstressed plants. These benefits were realized via stress activation of distinct EMF taxa, which suggests significant functional diversity within EMF assemblages. We developed and validated a model that predicts net N flux into the plant based on taxon-specific 15 N enrichment in ectomycorrhizal root tips. These results open a new avenue to characterize the functional traits of EMF taxa in complex communities.

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Dramatic changes in ectomycorrhizal community composition, root tip abundance and mycelial production along a stand‐scale nitrogen deposition gradient

Cited by 163 publications

References 46 publications

Distribution and drivers of ectomycorrhizal fungal communities across the North American Arctic

Distribution and drivers of ectomycorrhizal fungal communities across the North American Arctic

Fine-root trait plasticity of beech (Fagus sylvatica) and spruce (Picea abies) forests on two contrasting soils

Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress

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