Increases in aridity forecasted by the end of this century will decouple the cycles of soil carbon (C), nitrogen (N) and phosphorus (P) in drylands—the largest terrestrial biome on Earth. Little is known, however, about how changes in aridity simultaneously affect the C:N:P stoichiometry of organisms across multiple trophic levels. It is imperative that we understand how aridity affects ecological stoichiometry so that we can develop strategies to mitigate any effects of changing climates. We characterized the C, N, P concentration and stoichiometry of soils, autotrophs (trees, N-fixing shrubs, grasses and mosses) and heterotrophs (microbes and ants) across a wide aridity gradient in Australia. Our results suggest that increases in aridity by the end of this century may alter the C:N:P stoichiometry of heterotrophs (ants and microbes), non-woody plants and in soil, but will not affect that one from woody plants. In particular, increases in aridity were positively related to C:P and N:P ratios in microbes and ants, negatively related to concentration of C, and the C:N and C:P ratios in mosses and/or short grasses, and not related to the C:N:P stoichiometry of either shrubs or trees. Because of the predominant role of C:N:P stoichiometry in driving nutrient cycling, our findings provide useful contextual information to determine ecological responses in a drier world.
Bibliographical noteFunding Information:
This study was supported by the Australian Research Council (Project DP13010484; DP170104634), by GRDC (UWS00008) and by the European Research Council (ERC) under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 242658 (BIOCOM). M.D-B. also acknowledges support from the Marie Sklodowska-Curie Actions of the Horizon 2020 Framework Programme H2020-MSCA-IF-2016 under REA Grant Agreement No. 702057. DJE was supported by the Hermon Slade Foundation. FTM acknowledges support from the European Research Council (BIODESERT Project, ERC Grant Agreement No. 647038) and by the Spanish Ministry of Economy and Competitiveness (BIOMOD Project, CGL2013-44661-R).
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- soil microbes