Relative effects of precipitation variability and warming on tallgrass prairie ecosystem function

Precipitation and temperature drive many aspects of terrestrial ecosystem function. Climate change scenar- ios predict increasing precipitation variability and temper- ature, and long term experiments are required to evaluate the ecosystem consequences of interannual climate variation, increased growing season (intra-annual) rainfall variability, and warming. We present results from an experiment ap- plying increased growing season rainfall variability and year round warming in native tallgrass prairie. During ten years of study, total growing season rainfall varied 2-fold, and we found 50-200 % interannual variability in plant growth and aboveground net primary productivity (ANPP), leaf carbon assimilation (ACO2 ), and soil CO2 efflux ( JCO2 ) despite only 40 % variation in mean volumetric soil water content (0- 15 cm, 215). Interannual variation in soil moisture was thus amplified in most measures of ecosystem response. Dif- ferences between years in 215 explained the greatest por- tion (14-52 %) of the variation in these processes. Exper- imentally increased intra-annual season rainfall variability doubled the amplitude of intra-annual soil moisture varia- tion and reduced 215 by 15 %, causing most ecosystem pro- cesses to decrease 8-40 % in some or all years with increased rainfall variability compared to ambient rainfall timing, sug- gesting reduced ecosystem rainfall use efficiency. Warming treatments increased soil temperature at 5 cm depth, partic- ularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter JCO2 , and re- duced summer JCO2 and forb ANPP, suggesting that the ef- fects of warming differed in cooler versus warmer parts of the year. We conclude that (1) major ecosystem processes in this grassland may be substantially altered by predicted changes in interannual climate variability, intra-annual rain- fall variability, and temperature, (2) interannual climate vari- ation was a larger source of variation in ecosystem function than intra-annual rainfall variability and warming, and (3) effects of increased growing season rainfall variability and warming were small, but ecologically important. The relative effects of these climate drivers are likely to vary for different ecosystem processes and in wetter or drier ecosystems.

[1]  J. Craine,et al.  Climate controls on grass culm production over a quarter century in a tallgrass prairie. , 2010, Ecology.

[2]  S. Niu,et al.  Response of ecosystem carbon exchange to warming and nitrogen addition during two hydrologically contrasting growing seasons in a temperate steppe , 2009 .

[3]  A. Knapp,et al.  Ecophysiological responses of two dominant grasses to altered temperature and precipitation regimes , 2009 .

[4]  M. Almagro,et al.  Temperature dependence of soil CO2 efflux is strongly modulated by seasonal patterns of moisture availability in a Mediterranean ecosystem. , 2009 .

[5]  Zhe Zhang,et al.  Predominant role of water in regulating soil and microbial respiration and their responses to climate change in a semiarid grassland , 2009 .

[6]  T. Karl,et al.  Global climate change impacts in the United States. , 2009 .

[7]  D. Schimel,et al.  Lagged effects of experimental warming and doubled precipitation on annual and seasonal aboveground biomass production in a tallgrass prairie , 2008 .

[8]  Markus Reichstein,et al.  Consequences of More Extreme Precipitation Regimes for Terrestrial Ecosystems , 2008 .

[9]  A. Knapp,et al.  Increasing precipitation event size increases aboveground net primary productivity in a semi-arid grassland , 2008, Oecologia.

[10]  Dawn M. Kaufman,et al.  Changes in grassland ecosystem function due to extreme rainfall events: implications for responses to climate change , 2008 .

[11]  Randall D. Jackson,et al.  The sensitivity of annual grassland carbon cycling to the quantity and timing of rainfall , 2008 .

[12]  Pavel Ya. Groisman,et al.  Prolonged Dry Episodes over the Conterminous United States: New Tendencies Emerging during the Last 40 Years , 2008 .

[13]  R. Ceulemans,et al.  Biomass production in experimental grasslands of different species richness during three years of climate warming , 2007 .

[14]  R. Dickinson,et al.  Couplings between changes in the climate system and biogeochemistry , 2007 .

[15]  A. Knapp,et al.  Photosynthetic traits in C3 and C4 grassland species in mesocosm and field environments , 2007 .

[16]  A. Knapp,et al.  Soil water partitioning contributes to species coexistence in tallgrass prairie , 2007 .

[17]  A. Knapp,et al.  Linking water uptake with rooting patterns in grassland species , 2007, Oecologia.

[18]  Yiqi Luo,et al.  Divergence of reproductive phenology under climate warming , 2007, Proceedings of the National Academy of Sciences.

[19]  Christopher B. Field,et al.  Diverse responses of phenology to global changes in a grassland ecosystem , 2006, Proceedings of the National Academy of Sciences.

[20]  A. Knapp,et al.  Growth Responses of Two Dominant C4 Grass Species to Altered Water Availability , 2006, International Journal of Plant Sciences.

[21]  Yiqi Luo,et al.  Main and interactive effects of warming, clipping, and doubled precipitation on soil CO2 efflux in a grassland ecosystem , 2006 .

[22]  Yiqi Luo,et al.  Soil respiration and the environment , 2006 .

[23]  J. Briggs,et al.  Intra-annual rainfall variability and grassland productivity: can the past predict the future? , 2006, Plant Ecology.

[24]  Yiqi Luo,et al.  Plant nitrogen concentration, use efficiency, and contents in a tallgrass prairie ecosystem under experimental warming , 2005 .

[25]  R. Ceulemans,et al.  Grassland species will not necessarily benefit from future elevated air temperatures: a chlorophyll fluorescence approach to study autumn physiology , 2005 .

[26]  J. Harte,et al.  Dynamic and complex microclimate responses to warming and grazing manipulations , 2005 .

[27]  Christopher B Field,et al.  Responses of Grassland Production to Single and Multiple Global Environmental Changes , 2005, PLoS biology.

[28]  Yiqi Luo,et al.  Direct and indirect effects of experimental warming on ecosystem carbon processes in a tallgrass prairie , 2005 .

[29]  D. Easterling,et al.  Trends in Intense Precipitation in the Climate Record , 2005 .

[30]  J. Blair,et al.  Increased rainfall variability and reduced rainfall amount decreases soil CO 2 flux in a grassland ecosystem , 2005 .

[31]  P. Fay,et al.  Increased rainfall variability and reduced rainfall amount decreases soil CO 2 flux in a grassland ecosystem , 2005 .

[32]  T. Ricketts,et al.  Confronting a biome crisis: global disparities of habitat loss and protection , 2004 .

[33]  J. Zak,et al.  Convergence across biomes to a common rain-use efficiency , 2004, Nature.

[34]  J. Schaber,et al.  Responses of spring phenology to climate change , 2004 .

[35]  James F. Reynolds,et al.  Modifying the ‘pulse–reserve’ paradigm for deserts of North America: precipitation pulses, soil water, and plant responses , 2004, Oecologia.

[36]  Osvaldo E. Sala,et al.  Hierarchy of responses to resource pulses in arid and semi-arid ecosystems , 2004, Oecologia.

[37]  James F. Reynolds,et al.  Plant responses to precipitation in desert ecosystems: integrating functional types, pulses, thresholds, and delays , 2004, Oecologia.

[38]  A. Knapp,et al.  Water relations and growth of three grasses during wet and drought years in a tallgrass prairie , 1984, Oecologia.

[39]  C. Quan,et al.  Acclimatization of soil respiration to warming , 2004 .

[40]  C. Field,et al.  Plants reverse warming effect on ecosystem water balance , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[41]  J. Blair,et al.  Productivity responses to altered rainfall patterns in a C4-dominated grassland , 2003, Oecologia.

[42]  Yiqi Luo,et al.  Partitioning interannual variability in net ecosystem exchange between climatic variability and functional change. , 2003, Tree physiology.

[43]  J. Blair,et al.  Rainfall Variability, Carbon Cycling, and Plant Species Diversity in a Mesic Grassland , 2002, Science.

[44]  Alan K. Knapp,et al.  Altered Rainfall Patterns, Gas Exchange, and Growth in Grasses and Forbs , 2002, International Journal of Plant Sciences.

[45]  G. Davidowitz.  Does precipitation variability increase from mesic to xeric biomes , 2002 .

[46]  Gordon B. Bonan,et al.  Ecological Climatology: Concepts and Applications , 2002 .

[47]  Ray R. Weil,et al.  The Nature and Properties of Soils, 13th Edition , 2001 .

[48]  J. Harte,et al.  PLANT RESPONSES TO EXPERIMENTAL WARMING IN A MONTANE MEADOW , 2001 .

[49]  J. K. Koelliker,et al.  Frequency and Extent of Water Limitation to Primary Production in a Mesic Temperate Grassland , 2001, Ecosystems.

[50]  Alan K. Knapp,et al.  Altering Rainfall Timing and Quantity in a Mesic Grassland Ecosystem: Design and Performance of Rainfall Manipulation Shelters , 2000, Ecosystems.

[51]  W. Dugas,et al.  Soil CO2 flux in a tallgrass prairie , 2000 .

[52]  J. Harte,et al.  The effect of experimental ecosystem warming on CO2 fluxes in a montane meadow , 1999 .

[53]  A. Knapp,et al.  Is leaf-level photosynthesis related to plant success in a highly productive grassland? , 1998, Oecologia.

[54]  Alan K. Knapp,et al.  Grassland dynamics : long-term ecological research in tallgrass prairie , 1998 .

[55]  S. Heckathorn,et al.  The contribution of drought‐related decreases in foliar nitrogen concentration to decreases in photosynthetic capacity during and after drought in prairie grasses , 1997 .

[56]  J. Briggs,et al.  Interannual variability in primary production in tallgrass prairie: climate, soil moisture, topographic position, and fire as determinants of aboveground biomass , 1995 .

[57]  A. Knapp,et al.  Comparative Gas Exchange and Nitrogen Responses of the Dominant C4 Grass Andropogon gerardii and Five C3 Forbs to Fire and Topographic Position in Tallgrass Prairie During a Wet Year , 1995, International Journal of Plant Sciences.

[58]  Alan K. Knapp,et al.  Effect of Fire and Drought on the Ecophysiology of Andropogon gerardii and Panicum virgatum in a Tallgrass Prairie , 1985 .

[59]  I. Noy-Meir,et al.  Desert Ecosystems: Environment and Producers , 1973 .

[60]  T. L. Lyon,et al.  The Nature and Properties of Soils , 1930 .