Decoupling of soil nutrients cycles as a function of aridity in global drylands

The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability. The increase in aridity predicted for the twenty-first century in many drylands worldwide may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. Wefind a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition1. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.Fil: Delgado Baquerizo, Manuel. Universidad Pablo de Olavide; España. Universidad Rey Juan Carlos. Departamento de Biología y Geología. Área de Biodiversidad y Conservación; EspañaFil: Maestre, Fernando T.. Universidad Pablo de Olavide; España. Universidad Rey Juan Carlos. Departamento de Biología y Geología. Área de Biodiversidad y Conservación; EspañaFil: Gallardo, Antonio. Universidad Pablo de Olavide; EspañaFil: Bowker, Matthew A.. No especifíca;Fil: Wallenstein, Matthew D.. Northern Arizona University; Estados UnidosFil: Bran, Donaldo Eduardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina. Universidad Rey Juan Carlos. Departamento de Biología y Geología. Área de Biodiversidad y Conservación; EspañaFil: Gatica, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Hepper, Estela Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Pampa. Facultad de Agronomía; ArgentinaFil: Prina, Anibal Oscar. Universidad Nacional de La Pampa. Facultad de Agronomía; ArgentinaFil: Pucheta, Eduardo Raúl. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Huber Sannwald, Elisabeth. Instituto Potosino de Investigación Científica y Tecnológica; MéxicoFil: Jankju, Mohammad. Ferdowsi University of Mashhad; IránFil: Liu, Jushan. Northeast Normal University. Institute of Grassland Science,; ChinaFil: Mau, Rebecca L.. Northern Arizona University; Estados UnidosFil: Miriti, Maria. Ohio State University; Estados UnidosFil: Monerris, Jorge. Université du Québec a Montreal; CanadáFil: Naseri, Kamal. Ferdowsi University of Mashhad; IránFil: Noumi, Zouhaier. Université de Sfax; TúnezFil: Polo, Vicente. Universidad Rey Juan Carlos. Departamento de Biología y Geología. Área de Biodiversidad y Conservación; EspañaFil: Ramírez Collantes, David A.. International Potato Center; PerúFil: Romão, Roberto. Universidade Estadual de Feira de Santana. Departamento de Ciencias Biológica, Herbario; BrasilFil: Tighe, Matthew. University of New England; AustraliaFil: Torres, Duilio. Universidad Centroccidental ‘‘Lisandro Alvarado’’; VenezuelaFil: Torres Díaz, Cristian. Universidad del Bio Bio. Facultad de Ciencias. Departamento de Ciencias Básicas. Laboratorio de Genómica y Biodiversidad; ChileFil: Ungar, Eugene D.. The Volcani Center. Agricultural Research Organization. Institute of Plant Sciences; IsraelFil: Val, James. Office of Environment and Heritage; AustraliaFil: Wamiti, Wanyoike. National Museums of Kenya. Zoology Department; KeniaFil: Wang, Deli. Northeast Normal University. Institute of Grassland Science; ChinaFil: Zaady, Eli. Gilat Research Center; Israe