Plant community composition mediates both large transient decline and predicted long‐term recovery of soil carbon under climate warming

[1] We integrated two methods, experimental heating and observations across natural climate gradients, to elucidate both short- and long-term climatic controls on ecosystem carbon storage and to investigate carbon-cycle feedbacks to climate in montane meadows. A 10-year heating experiment warmed and dried heated plot soils and substantially decreased (by ∼200 ± 150 g C m−2) the amount of carbon stored in soil organic matter, a positive feedback to warming. In situ CO2 flux measurements, laboratory soil incubations, and a heating-induced shift in vegetation community composition from high- to low-productivity species indicate that a decline in community productivity and resultant decrease in soil inputs from plant litter caused most of the soil carbon decrease. An alternative widely hypothesized mechanism for soil carbon decrease under warming is stimulation of soil respiration, but we observed no increase in seasonally integrated soil respiration in our experiment (soil drying inhibited microbial decomposition even as soil warming stimulated it). To extend our analysis from the short-term transient response represented by the heating experiment to the presumed long-term approximate steady state represented by natural climate gradients, we tested a hypothesized relation between vegetation community composition (which controls both litter input rate and average litter quality) and soil carbon along the climate gradient. The gradient analysis implies that the experimentally induced decline in soil carbon is transient and will eventually reverse as lower quality litter inputs from the increasingly dominant low-productivity species reduce soil respiration losses. This work shows that ecological processes can control both short- and long-term responses to climate change, confirming some model-based predictions about the importance of vegetation shifts, but challenging the widely held hypothesis that the effect of temperature change on respiration will dominate soil carbon changes.

[1]  F. Stuart Chapin,et al.  Responses of Arctic Tundra to Experimental and Observed Changes in Climate , 1995 .

[2]  M. P.R.,et al.  A METHOD FOR SCALING VEGETATION DYNAMICS: THE ECOSYSTEM DEMOGRAPHY MODEL (ED) , 2022 .

[3]  S. Bridgham,et al.  RESPONSE OF BOG AND FEN PLANT COMMUNITIES TO WARMING AND WATER‐TABLE MANIPULATIONS , 2000 .

[4]  W. Schlesinger,et al.  The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate , 1992 .

[5]  Yiqi Luo,et al.  Acclimatization of soil respiration to warming in a tall grass prairie , 2001, Nature.

[6]  K. Iiyama,et al.  Determination of lignin in herbaceous plants by an improved acetyl bromide procedure , 1990 .

[7]  S. Trumbore,et al.  Comparison of Fractionation Methods for Soil Organic Matter 14C Analysis , 1996, Radiocarbon.

[8]  Mike Rees,et al.  5. Statistics for Spatial Data , 1993 .

[9]  M. V. Price,et al.  EFFECTS OF EXPERIMENTAL WARMING ON PLANT REPRODUCTIVE PHENOLOGY IN A SUBALPINE MEADOW , 1998 .

[10]  Anthropogenic (super 14) C variations in atmospheric CO (sub 2) and wines. , 2006 .

[11]  B. DeAngelo,et al.  TERRESTRIAL ECOSYSTEM FEEDBACKS TO GLOBAL CLIMATE CHANGE , 1997 .

[12]  R. B. Jackson,et al.  Detecting changes in soil carbon in CO2 enrichment experiments , 1995, Plant and Soil.

[13]  Gas exchange and water relations of two Rocky Mountain shrub species exposed to a climate change manipulation , 2000, Plant Ecology.

[14]  D. O. Hall,et al.  Impact of climate change on grassland production and soil carbon worldwide , 1995 .

[15]  J. Hansen,et al.  Climate-chemical interactions and effects of changing atmospheric trace gases , 1987 .

[16]  D. S. Jenkinson,et al.  THE TURNOVER OF SOIL ORGANIC MATTER IN SOME OF THE ROTHAMSTED CLASSICAL EXPERIMENTS , 1977 .

[17]  J. Randerson,et al.  Terrestrial ecosystem production: A process model based on global satellite and surface data , 1993 .

[18]  S. Idso.  Greenhouse-Impact on Cold-Climate Ecosystems and Landscapes , 1993 .

[19]  M. Lebrón,et al.  The Natural Vegetation of North America: An Introduction. , 1979 .

[20]  F. Woodward,et al.  Dynamic responses of terrestrial ecosystem carbon cycling to global climate change , 1998, Nature.

[21]  H. Jenny,et al.  Factors of Soil Formation , 1941 .

[22]  V. Meentemeyer,et al.  Litter mass loss rates in pine forests of Europe and Eastern United States: some relationships with climate and litter quality , 1993 .

[23]  J. Aber,et al.  Responses of Trace Gas Fluxes and N Availability to Experimentally Elevated Soil Temperatures , 1994 .

[24]  E. Rastetter,et al.  Effects of Plant Growth Characteristics on Biogeochemistry and Community Composition in a Changing Climate , 1999, Ecosystems.

[25]  D. Jenkinson,et al.  Model estimates of CO2 emissions from soil in response to global warming , 1991, Nature.

[26]  A. Kinzig,et al.  Global Warming and Soil Microclimate: Results from a Meadow‐Warming Experiment , 1995 .

[27]  K. Nadelhoffer,et al.  EFFECTS OF TEMPERATURE AND SUBSTRATE QUALITY ON ELEMENT MINERALIZATION IN SIX ARCTIC SOILS , 1991 .

[28]  J. Harte,et al.  Shifting Dominance Within a Montane Vegetation Community: Results of a Climate-Warming Experiment , 1995, Science.

[29]  John Harte,et al.  SUBALPINE MEADOW FLOWERING PHENOLOGY RESPONSES TO CLIMATE CHANGE: INTEGRATING EXPERIMENTAL AND GRADIENT METHODS , 2003 .

[30]  M. Shaw,et al.  CONTROL OF LITTER DECOMPOSITION IN A SUBALPINE MEADOW-SAGEBRUSH STEPPE ECOTONE UNDER CLIMATE CHANGE , 2001 .

[31]  F. Chapin,et al.  CLIMATIC EFFECTS ON TUNDRA CARBON STORAGE INFERRED FROM EXPERIMENTAL DATA AND A MODEL , 1997 .

[32]  K. Tate.  Assessment, based on a climosequence of soils in tussock grasslands, of soil carbon storage and release in response to global warming , 1992 .

[33]  Thomas R. Karl,et al.  Observed Impact of Snow Cover on the Heat Balance and the Rise of Continental Spring Temperatures , 1994, Science.

[34]  P. Matson,et al.  CARBON CYCLING AND SOIL CARBON STORAGE IN MESIC TO WET HAWAIIAN MONTANE FORESTS , 2001 .

[35]  R. Whittaker.  Communities and Ecosystems , 1975 .

[36]  P. Vitousek,et al.  Soil organic matter dynamics along gradients in temperature and land use on the Island of Hawaii , 1995 .

[37]  Harden,et al.  Sensitivity of boreal forest carbon balance to soil thaw , 1998, Science.

[38]  Steven W. Leavit.  Biogeochemistry, An Analysis of Global Change , 1998 .

[39]  David Pollard,et al.  Coupling dynamic models of climate and vegetation , 1998 .

[40]  F. Bazzaz,et al.  Microevolutionary responses in experimental populations of plants to CO2-enriched environments: parallel results from two model systems. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

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

[42]  I. Burke,et al.  Soil organic matter and nutrient availability responses to reduced plant inputs in shortgrass steppe , 1996 .

[43]  J. Vogel.  Rapid Production of Graphite Without Contamination for Biomedical AMS , 1992, Radiocarbon.

[44]  A. Austin.  DIFFERENTIAL EFFECTS OF PRECIPITATION ON PRODUCTION AND DECOMPOSITION ALONG A RAINFALL GRADIENT IN HAWAII , 2002 .

[45]  Thomas H. Painter,et al.  Climatic, edaphic, and biotic controls over storage and turnover of carbon in soils , 1994 .

[46]  F. Stuart Chapin,et al.  Species composition interacts with fertilizer to control long-term change in tundra productivity , 2001 .

[47]  Noel A. C. Cressie,et al.  Statistics for Spatial Data: Cressie/Statistics , 1993 .

[48]  J. Harte,et al.  Changes in water relations for leaves exposed to a climate-warming manipulation in the Rocky Mountains of Colorado , 1997 .

[49]  F. Stuart Chapin,et al.  THE RESPONSE OF TUNDRA PLANT BIOMASS, ABOVEGROUND PRODUCTION, NITROGEN, AND CO2 FLUX TO EXPERIMENTAL WARMING , 1998 .

[50]  F. Chapin,et al.  Response of tundra CH4 and CO2 flux tomanipulation of temperature and vegetation , 1998 .

[51]  Robert Haining,et al.  Statistics for spatial data: by Noel Cressie, 1991, John Wiley & Sons, New York, 900 p., ISBN 0-471-84336-9, US $89.95 , 1993 .

[52]  M. Stuiver,et al.  Discussion: Reporting of 14 C Data , 1977 .

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

[54]  H. Craig.  Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide , 1957 .

[55]  J. Harte,et al.  Methane consumption by montane soils: implications for positive and negative feedback with climatic change , 1996 .

[56]  Peter M. Vitousek,et al.  Tropical soils could dominate the short-term carbon cycle feedbacks to increased global temperatures , 1992 .

[57]  Edward B. Rastetter,et al.  Global Change and the Carbon Balance of Arctic EcosystemsCarbon/nutrient interactions should act as major constraints on changes in global terrestrial carbon cycling , 1992 .

[58]  M. Kirschbaum,et al.  The temperature dependence of soil organic matter decomposition, and the effect of global warming on soil organic C storage , 1995 .

[59]  James S. Clark,et al.  Terrestrial biotic responses to environmental change and feedbacks to climate , 1996 .

[60]  R. Amundson,et al.  Rapid Exchange Between Soil Carbon and Atmospheric Carbon Dioxide Driven by Temperature Change , 1996, Science.

[61]  H. Shugart,et al.  The transient response of terrestrial carbon storage to a perturbed climate , 1993, Nature.