Multiple distinct, scale‐dependent links between fungi and decomposition

Abstract

Decomposition has historically been considered a function of climate and substrate but new research highlights the significant role of specific micro‐organisms and their interactions. In particular, wood decay is better predicted by variation in fungal communities than in climate. Multiple links exist: interspecific competition slows decomposition in more diverse fungal communities, whereas trait variation between different communities also affects process rates. Here, we paired field and laboratory experiments using a dispersal gradient at a forest‐shrubland ecotone to examine how fungi affect wood decomposition across scales. We observed that while fungal communities closer to forests were capable of faster decomposition, wood containing diverse fungal communities decomposed more slowly, independent of location. Dispersal‐driven stochasticity in small‐scale community assembly was nested within large‐scale turnover in the regional species pool, decoupling the two patterns. We thus find multiple distinct links between microbes and ecosystem function that manifest across different spatial scales.

Belowground community turnover accelerates the decomposition of standing dead wood

“…2014, Griffiths et al. 2021, Smith and Peay 2021) as also observed in our current study for both interface and buried wood (Figs. 1 and 2).…”

“…As such, given insights from mathematical proofs such as Jensen's inequality (Ruel and Ayres 1999), the high variation in moisture that we observed poses particularly difficult challenges for scaling causative relationships between microclimate moisture and wood decomposition, to stand and regional scales relevant to forest carbon budget and biodiversity projections (see Heffernan et al [2014]). These challenges will be magnified by the fact that decomposition rates of downed wood at the same location and with variables such as wood species and log size controlled for, is itself highly variable (Bradford et al 2014, Griffiths et al 2021, Smith and Peay 2021 as also observed in our current study for both interface and buried wood (Figs. 1 and 2).…”

A framework for integrating microbial dispersal modes into soil ecosystem ecology

“…Dispersal-colonization tradeoffs may structure microbial trait distributions across the spatial and environmental landscape ( Smith et al., 2018 ). In a recent wood decomposition study spanning sites along a forest/non-forest ecotone, dispersal limitation of traits associated with rapid wood-degradation shaped community composition and function such that fungal communities farther from forests decomposed wood blocks more slowly ( Smith and Peay, 2021 ). Independent of forest proximity, there was also a significant negative relationship between alpha-diversity (shaped by stochastic dispersal) and decomposition because of interspecific competition, linking dispersal to independent drivers of community function in this system ( Smith and Peay, 2021 ).…”

Emission of CO2 and CH4 From 13 Deadwood Tree Species Is Linked to Tree Species Identity and Management Intensity in Forest and Grassland Habitats

“…For temperate regions, canopy openness leads to decreasing moisture and increasing temperature, which is mostly beneficial to overall diversity and resulting in a saproxylic community that is distinct from more shaded conditions (Seibold et al., 2016; Vogel et al., 2020). In addition, Smith and Peay (2021) showed a shift and decrease in decomposing fungi with a forest to shrubland gradient. As deforestation has led to an increased grassland area in temperate regions (Hoekstra et al., 2005), these habitats coming into focus.…”