caa a22 4500 467885311 CHVBK 20180406152732.0 cr unu---uuuuu 170328e20060901xx s 000 0 eng 10.1007/s10021-005-0093-7 doi (NATIONALLICENCE)springer-10.1007/s10021-005-0093-7 Soil Temperature, Not Aboveground Plant Productivity, Best Predicts Intra-Annual Variations of Soil Respiration in Central Iowa Grasslands [Elektronische Daten] [Mathew Dornbush, James Raich] Soil respiration (RSOIL) is the second largest carbon flux between terrestrial systems and the atmosphere, with a magnitude 10 times greater than anthropogenic carbon dioxide production. Therefore, it is important that we understand, and be able to predict, how RSOIL responds to climate change. Although a positive, significant temperature effect on RSOIL has long been recognized, recent studies emphasize the overriding importance of current photosynthesis in controlling RSOIL. We tested the hypothesis that model inclusion of intra-annual variations in aboveground net primary productivity (ANPP) significantly improves RSOIL estimates over predictions based on soil temperature alone. We also evaluated the possibility that canopy production is less directly linked to RSOIL, by testing the hypothesis that intersite differences in RSOIL correlate more strongly with root biomass than with ANPP. We tested these hypotheses by measuring RSOIL, ANPP, and root biomass at four Iowa grasslands that differed in aboveground growth phenology and productivity. Among all sites, intra-annual variations in RSOIL were most strongly related to soil temperature (R 2 = 0.89), not ANPP (R 2 = 0.53). All sites responded identically to changes in soil temperature (site-by-temperature P = 0.53), but inconsistently to variation in aboveground dynamics (site-by-canopy P < 0.0001). Incorporating canopy dynamics into temperature-based predictive models improved model R 2 by a maximum of 0.01. Among-site differences in RSOIL were related to root biomass (P < 0.001) but not ANPP (P = 0.34). We found no useful linkage between canopy characteristics and intra-annual or site-specific RSOIL predictions, perhaps because shoot and root dynamics were not consistently linked through time or among sites. Springer Science+Business Media, Inc., 2006 C3 versus C4 nationallicence net primary productivity nationallicence plant phenology nationallicence root biomass nationallicence soil carbon dioxide flux nationallicence standing live biomass nationallicence Iowa grasslands nationallicence Dornbush Mathew Department of Natural and Applied Sciences, University of Wisconsin-Green Bay, 2420 Nicolet Drive, 54311, Green Bay, Wisconsin, USA aut Raich James Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 253 Bessey Hall, 50011, Ames, Iowa, USA aut Ecosystems Springer-Verlag; www.springer-ny.com 9/6(2006-09-01), 909-920 1432-9840 9:6<909 2006 9 10021 https://doi.org/10.1007/s10021-005-0093-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0093-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dornbush Mathew Department of Natural and Applied Sciences, University of Wisconsin-Green Bay, 2420 Nicolet Drive, 54311, Green Bay, Wisconsin, USA aut NATIONALLICENCE 700 1- Raich James Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 253 Bessey Hall, 50011, Ames, Iowa, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/6(2006-09-01), 909-920 1432-9840 9:6<909 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer