Temperature thresholds drive the global distribution of soil fungal decomposers

• Published in: Global change biology Vol. 28; no. 8; pp. 2779 - 2789
• Main Authors: Feng, Youzhi, Zhang, Jianwei, Berdugo, Miguel, Guirado, Emilio, Guerra, Carlos A., Egidi, Eleonora, Wang, Juntao, Singh, Brajesh K., Delgado‐Baquerizo, Manuel
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2022
• Subjects: air; Air temperature; Aridity; biodiversity; biogeography; Carbon; Carbon content; Carbon Cycle; Climate change; Decomposers; Decomposition; Distribution; Ecosystem; fungal communities; fungal decomposers; Fungi; geographical distribution; global carbon budget; global change; Global warming; Relative abundance; Soil; soil carbon; soil decomposition; soil fungi; Soil Microbiology; Soil temperature; Soils; Surveying; surveys; Temperature; Temperature gradients; Thresholds; fungal decomposers; soil decomposition; biodiversity; biogeography; global change
• ISSN: 1354-1013; 1365-2486; 1365-2486
• DOI: 10.1111/gcb.16096

Unraveling the biogeographic pattern of soil fungal decomposers along temperature gradients—in smooth linearity or an abrupt jump—can help us connect the global carbon cycle to global warming. Through a standardized global field survey, we identify the existence of temperature thresholds that control the global distribution of soil fungal decomposers, leading to abrupt reductions in their proportion (i.e., the relative abundance in the fungal community) immediately after crossing particular air and soil temperature thresholds. For example, small increases over the mean annual temperature threshold of ~9°C result in abrupt reductions in their proportion, paralleling a similar temperature threshold for soil carbon content. We further find that the proportion of soil fungal decomposers is more sensitive to temperature increases under arid conditions. Given the positive correlation between the global distributions of fungal decomposers and soil heterotrophic respiration, the reported temperature‐driven abrupt reductions in fungal decomposers could further suppress their driven soil decomposition processes and reduce carbon fluxes from soils to the atmosphere with implications for climate change feedback. This work not only advances the current knowledge on the global distribution of soil fungal decomposers, but also highlights that small changes in temperature around certain thresholds can lead to potential unexpected consequences in global carbon cycling under projected climate change. We do not know whether soil fungal decomposers follow linear or drastic changes in response to increases in temperature, limiting our understanding of how carbon cycling will respond to global warming. We found that temperature thresholds drive the distribution of soil fungal decomposers globally, especially in dry environments. Small increases in temperature over ~9ºC can result in drastic reductions in their abundance and soil carbon content, which were positively correlated with soil heterotrophic respiration worldwide. Our work highlights that temperature thresholds drive the global distribution of soil fungal decomposers with potential implications for carbon cycling and climate change in the future.