TY - JOUR T1 - Influence of climate variability on plant production and N-mineralization in Central US grasslands JF - Journal of Vegetation Science Y1 - 2002 A1 - Barrett, J.E. A1 - McCulley, R.L. A1 - Lane, D.R. A1 - Burke, I.C. A1 - Lauenroth, W.K. KW - Annual variation KW - ANPP KW - Central Grasslands region KW - Environmental gradient KW - IGBP Transect KW - Mineralization KW - Nitrogen flux KW - Seasonal variation AB - We assessed the influence of annual and seasonal climate variability over soil organic matter (SOM), above-ground net primary production (ANPP) and in situ net nitrogen (N) mineralization in a regional field study across the International Geosphere Biosphere Programme (IGBP) North American mid-latitude transect (Koch et al. 1995). We hypothesized that while trends in SOM are strongly correlated with mean climatic parameters, ANPP and net N-mineralization are more strongly influenced by annual and seasonal climate because they are dynamic processes sensitive to short-term variation in temperature and water availability. Seasonal and monthly deviations from long-term climatic means, particularly precipitation, were greatest at the semi-arid end of the transect. ANPP is sensitive to this climatic variability, but is also strongly correlated with mean annual climate parameters. In situ net N-mineralization and nitrification were weakly influenced by soil water content and temperature during the incubation and were less sensitive to seasonal climatic variables than ANPP, probably because microbial transformations of N in the soil are mediated over even finer temporal scales. We found no relationship between ANPP and in situ net N-mineralization. These results suggests that methods used to estimate in situ net N-mineralization are inadequate to represent N-availability across gradients where microbial biomass, N-immobilization or competition among plants and microbes vary. VL - 13 ER -