Fungi are major drivers of ecosystem functioning. Increases in aridity are known to negatively impact fungal community composition in dryland ecosystems globally; yet, much less is known on the potential influence of other environmental drivers, and whether these relationships are linear or nonlinear.
Time period2017\uffe2\uff80\uff932021.
LocationGlobal.
Major taxa studiedFungi.
MethodsWe re\uffe2\uff80\uff90analysed multiple datasets from different dryland biogeographical regions, for a total of 912 samples and 1,483 taxa. We examined geographical patterns in community diversity and composition, and spatial, edaphic and climatic factors driving them.
ResultsUV index, climate seasonality, and sand content were the most important environmental predictors of community shifts, showing the strongest association with the richness of putative plant pathogens and saprobes. Important nonlinear relationships existed with each of these fungal guilds, with increases in UV and temperature seasonality above 7.5 and 900 SD (standard deviation x 100 of the mean monthly temperature), respectively, being associated with an increased probability of plant pathogen and unspecified saprotroph occurrence. Conversely, these environmental parameters had a negative relationship with litter and soil saprotroph richness. Consequently, these ecological groups might be particularly sensitive to shifts in UV radiation and climate seasonality, which is likely to disturb current plant\uffe2\uff80\uff93soil dynamics in drylands.
Main conclusionsOur synthesis integrates fungal community data from drylands across the globe, allowing the investigation of fungal distribution and providing the first evidence of shifts in fungal diversity and composition of key fungal ecological groups along diverse spatial, climatic and edaphic gradients in these widely distributed ecosystems. Our findings imply that shifts in soil structure and seasonal climatic patterns induced by global change will have disproportionate consequences for the distribution of fungal groups linked to vegetation and biogeochemical cycling in drylands, with implications for plant\uffe2\uff80\uff93soil interactions in drylands.Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2\uffc2\uffa0m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1\uffe2\uff80\uff90km2resolution for 0\uffe2\uff80\uff935 and 5\uffe2\uff80\uff9315\uffc2\uffa0cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1\uffe2\uff80\uff90km2pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse\uffe2\uff80\uff90grained air temperature estimates from ERA5\uffe2\uff80\uff90Land (an atmospheric reanalysis by the European Centre for Medium\uffe2\uff80\uff90Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10\uffc2\uffb0C (mean\uffc2\uffa0=\uffc2\uffa03.0\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.1\uffc2\uffb0C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.3\uffc2\uffb0C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (\uffe2\uff88\uff920.7\uffc2\uffa0\uffc2\uffb1\uffc2\uffa02.3\uffc2\uffb0C). The observed substantial and biome\uffe2\uff80\uff90specific offsets emphasize that the projected impacts of climate and climate change on near\uffe2\uff80\uff90surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil\uffe2\uff80\uff90related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.Fungi are major drivers of ecosystem functioning. Increases in aridity are known to negatively impact fungal community composition in dryland ecosystems globally; yet, much less is known on the potential influence of other environmental drivers, and whether these relationships are linear or nonlinear.
Time period2017\uffe2\uff80\uff932021.
LocationGlobal.
Major taxa studiedFungi.
MethodsWe re\uffe2\uff80\uff90analysed multiple datasets from different dryland biogeographical regions, for a total of 912 samples and 1,483 taxa. We examined geographical patterns in community diversity and composition, and spatial, edaphic and climatic factors driving them.
ResultsUV index, climate seasonality, and sand content were the most important environmental predictors of community shifts, showing the strongest association with the richness of putative plant pathogens and saprobes. Important nonlinear relationships existed with each of these fungal guilds, with increases in UV and temperature seasonality above 7.5 and 900 SD (standard deviation x 100 of the mean monthly temperature), respectively, being associated with an increased probability of plant pathogen and unspecified saprotroph occurrence. Conversely, these environmental parameters had a negative relationship with litter and soil saprotroph richness. Consequently, these ecological groups might be particularly sensitive to shifts in UV radiation and climate seasonality, which is likely to disturb current plant\uffe2\uff80\uff93soil dynamics in drylands.
Main conclusionsOur synthesis integrates fungal community data from drylands across the globe, allowing the investigation of fungal distribution and providing the first evidence of shifts in fungal diversity and composition of key fungal ecological groups along diverse spatial, climatic and edaphic gradients in these widely distributed ecosystems. Our findings imply that shifts in soil structure and seasonal climatic patterns induced by global change will have disproportionate consequences for the distribution of fungal groups linked to vegetation and biogeochemical cycling in drylands, with implications for plant\uffe2\uff80\uff93soil interactions in drylands.