Functional diversity in resource use by fungi

Abstract

Fungi influence nutrient cycling in terrestrial ecosystems, as they are major regulators of decomposition and soil respiration. However, little is known about the substrate preferences of individual fungal species outside of laboratory culture studies. If active fungi differ in their substrate preferences in situ, then changes in fungal diversity due to global change may dramatically influence nutrient cycling in ecosystems. To test the responses of individual fungal taxa to specific substrates, we used a nucleotide-analogue procedure in the boreal forest of Alaska (USA). Specifically, we added four organic N compounds commonly found in plant litter (arginine, glutamate, lignocellulose, and tannin-protein) to litterbags filled with decomposed leaf litter (black spruce and aspen) and assessed the responses of active fungal species using qPCR (quantitative polymerase chain reaction), oligonucleotide fingerprinting of rRNA genes, and sequencing. We also compared the sequences from our experiment with a concurrent warming experiment to see if active fungi that targeted more recalcitrant compounds would respond more positively to soil warming. We found that individual fungal taxa responded differently to substrate additions and that active fungal communities were different across litter types (spruce vs. aspen). Active fungi that targeted lignocellulose also responded positively to experimental warming. Additionally, resource-use patterns in different fungal taxa were genetically correlated, suggesting that it may be possible to predict the ecological function of active fungal communities based on genetic information. Together, these results imply that fungi are functionally diverse and that reductions in fungal diversity may have consequences for ecosystem functioning.

Environmental filtering affects soil fungal community composition more than dispersal limitation at regional scales

“…Moreover, soil nutrient concentrations have been linked to shifts in fungal composition in a variety of ecosystems (Dickie et al, 2002;Lilleskov et al, 2002;Hoffland et al, 2004;Allison et al, 2007;Johnson et al, 2010), and are particularly relevant in southern California where nitrogen deposition can affect fungal communities (Egerton-Warburton and Allen, 2000). Since fungal taxa are known to specialize on different nutrients (McGuire et al, 2010) and environmental conditions Kivlin et al, 2011), it is not surprising that these same abiotic factors largely controlled the composition of soil fungi in our sites. The interactions between environmental filtering over space that we observed may indicate reduced dispersal capabilities for some fungal taxa, especially for the 2/3rds of the soil fungal taxa that were not found in airborne samples.…”

Responses of Soil Fungi to Logging and Oil Palm Agriculture in Southeast Asian Tropical Forests

“…However, EcM fungi are known to produce abundant extracellular enzymes that differ among EcM fungal species [92,103], so it is likely that a fraction of the enzymatic activity detected in the soil was derived from EcM foraging. Decomposer fungi are also known to differ in their physiological capacities [104,105]; thus, it is likely that the differences in extracellular enzyme activity across land-use types will be reflected in other fungal-mediated nutrient cycling processes.…”

Fungal Traits That Drive Ecosystem Dynamics on Land

“…4. The response to warming and drying of each fungal taxon was calculated as the Cohen's d effect size (298) and averaged within each phylum/subphylum. Cohen's d is the difference between the treatment mean and the control mean divided by the pooled standard deviation.…”