Climate drives the spatial distribution of mycorrhizal host plants in terrestrial ecosystems

Abstract

1. Mycorrhizal associations have massive impacts on ecosystem functioning, but the mode and magnitude heavily depend on the mycorrhizal type involved. Different types of mycorrhizas are recognized to predominate under different environmental conditions. However, the respective importance of climate and soil characteristics in shaping mycorrhizal global distributions are still poorly understood. 2. We provide a quantitative and comprehensive global analysis of the main climatic and edaphic predictors of the distribution of plants featuring different mycorrhizal types. Estimates on per grid-cell relative above-ground biomass of plants holding arbuscular mycorrhiza (AM), ectomycorrhiza (EcM) and ericoid mycorrhiza (ErM) association were related to a set of 39 climatic and edaphic variables. We assessed their relationship by applying a Generalized Additive Models for Location, Scale and Shape (GAMLSS). 3. The best GAMLSS models were able to explain 55%, 41% and 46% of the variance in AM, EcM and ErM distribution, respectively. Temperature-related factors were the main predictors of distribution patterns for the three different mycorrhizal plant types. AM plants are favoured by warm climates, while EcM plants' dominance (and to some extent ErM plants too) is favoured by colder climates. 4. Synthesis. The observed lack of importance of soil drivers challenges the predominant view that mycorrhizal plants distribution mainly reflects soil type preferences-as related to its nutrient foraging strategies-of the different mycorrhizal types. Instead, our results highlight climate-and particularly temperature-as the main force shaping the distribution of arbuscular mycorrhiza, ectomycorrhiza and ericoid mycorrhiza host plants at the global scale and suggest that climate change can significantly alter the distribution of mycorrhizal host plants, with a subsequent impact on ecosystem functioning. K E Y W O R D S Arbuscular mycorrhiza, biogeography and macroecology, climate, ectomycorrhiza, environmental drivers, ericoid mycorrhiza, mycorrhizal distribution, soil properties | 2565 Journal of Ecology BARCELÓ Et AL.

Limiting similarity shapes the functional and phylogenetic structure of root neighborhoods in a subtropical forest

“…This may be associated with the partitioning of different soil nutrients, such as phosphorus (P) and nitrogen (N), between arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) species (Phillips & Fahey, 2006; Liu et al ., 2018). However, the patterns observed here contrasted with large‐scale species distributions that indicated contrasting habitat preference of AM and EcM species (Barceló et al ., 2019). An explanation for the discrepancy might be that, whereas previous studies exploring species co‐occurrences have usually been based on aboveground measurements, root systems may show higher overlap than suggested by tree canopies (Mou et al ., 1995; Jones et al ., 2011).…”

Tree species effects on topsoil carbon stock and concentration are mediated by tree species type, mycorrhizal association, and N-fixing ability at the global scale

“…Although mycorrhizal association of tree species mainly relates to their phylogeny (Koele et al, 2012), the dominant mycorrhizal association of a forest community can also be influenced by climate and soil conditions (Barceló et al, 2019). In general, AM trees increase in dominance in subtropical and lowland tropical forests where nutrient mineralization processes are fast, nevertheless ECM-associated tree species tend to dominate in cooler environments where the decomposition of organic matter occurs at a slower rate (Read and Perez-Moreno, 2003; Soudzilovskaia et al, 2015), indicating that climate and location may indirectly affect tree species effects on soil C stocks.…”

Global mycorrhizal fungal range sizes vary within and among mycorrhizal guilds but are not correlated with dispersal traits

“…AM fungi typically have broader host ranges compared to EM fungi (Matheny et al., 2009;Opik et al., 2010;Veresoglou & Rillig, 2014), allowing AM fungi to persist in more geographic locations than EM fungi. Parsing environmental versus plant host influence on below‐ground mycorrhizal fungi is difficult because mycorrhizal plant distributions are also influenced by abiotic climatic drivers (Barcelo et al., 2019). Ultimately, global surveys of multiple plant hosts across a variety of ecosystems will resolve the abiotic versus biotic component of mycorrhizal fungal niches.…”

“…Averill et al., 2019;Averill, Turner, & Finzi, 2014;Keller & Phillips, 2019;Sulman et al., 2019). Historically, most biogeographic maps of mycorrhizal associations relied on host plant mycorrhizal types (Barcelo, Bodegom, & Soudzilovskaia, 2019;Bueno et al., 2017;Steidinger et al., 2019). Recently, both plant and mycorrhizal fungal distributions have been considered together (Toussaint et al.…”