Net primary production and carbon stocks in differently managed grasslands: simulation of site-specific sensitivity to an increase in atmospheric CO2 and to climate change

Elevated atmospheric CO2 and climate changes are expected to influence managed grassland ecosystems. The mechanistic pasture simulation model (PaSim) was used to quantify effects on net primary productivity (NPP) and carbon (C) stocks at three locations differing in climate and soil type. An earlier model version was modified to enable long-term simulations at different altitudes, and to consider management in the form of either cutting or grazing by lactating cows. Results from simulations under current conditions agreed favourably with measured data for yield and C stocks, and model behaviour appeared to be plausible. Elevated CO2 alone or in combination with increased temperature stimulated NPP at all sites. The stimulation was positively related to increasing precipitation at dry sites, but negatively at cool sites. Climate change scenarios in combination with elevated CO2 led to increase C stocks. The sensitivity of C stocks to changes in temperature and precipitation was similar, and much larger than to management. Grazing led to higher C stocks compared with cutting, depending mainly on the difference in NPP between the management options. Grazing had a positive effect on C stocks under cool conditions, but the effect tended to become negative with increasing temperature. Comparing different sites revealed that local conditions affect system behaviour qualitatively. In quantitative terms, the results confirm that the combination of elevated CO2 and climate change affects NPP and C stocks, and that the influence of management is site-specific. © 2000 Elsevier Science B.V. All rights reserved.

[1]  G. Buyanovsky,et al.  Changing role of cultivated land in the global carbon cycle , 1998, Biology and Fertility of Soils.

[2]  De Chen,et al.  ASSESSMENT OF GRASSLAND ECOSYSTEM RESPONSES TO ATMOSPHERIC CHANGE USING LINKED PLANT–SOIL PROCESS MODELS , 1997 .

[3]  David S. Schimel,et al.  Texture, climate, and cultivation effects on soil organic matter content in U.S. grassland soils , 1989 .

[4]  H. Lambers,et al.  The causes of inherently slow growth in alpine plants : an analysis based on the underlying carbon economies of alpine and lowland Poa species , 1996 .

[5]  J. Fuhrer,et al.  Using an ecosystem model linked to GCM‐derived local weather scenarios to analyse effects of climate change and elevated CO2 on dry matter production and partitioning, and water use in temperate managed grasslands , 1999 .

[6]  Edward B. Rastetter,et al.  RESPONSES OF N‐LIMITED ECOSYSTEMS TO INCREASED CO2: A BALANCED‐NUTRITION, COUPLED‐ELEMENT‐CYCLES MODEL , 1997 .

[7]  N. Batjes,et al.  Mitigation of atmospheric CO2 concentrations by increased carbon sequestration in the soil , 1998, Biology and Fertility of Soils.

[8]  J. H. M. Thornley,et al.  A model of nitrogen flows in grassland , 1989 .

[9]  J. D. Hanson,et al.  FORAGE: a model of forage intake in beef cattle , 1992 .

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

[11]  I. E. Woodrow,et al.  A Model Predicting Stomatal Conductance and its Contribution to the Control of Photosynthesis under Different Environmental Conditions , 1987 .

[12]  C. Körner,et al.  Leaf Diffusive Conductances in the Major Vegetation Types of the Globe , 1995 .

[13]  Hari Eswaran,et al.  Organic Carbon in Soils of the World , 1993 .

[14]  A. Parshotam,et al.  The Rothamsted soil-carbon turnover model — discrete to continuous form , 1996 .

[15]  Bruno Mary,et al.  Modelling temperature and moisture effects on C-N transformations in soils: comparison of nine models , 1997 .

[16]  Donald A. Klein,et al.  Simulation model for the effects of climate change on temperate grassland ecosystems , 1991 .

[17]  Mingkui Cao,et al.  Net primary and ecosystem production and carbon stocks of terrestrial ecosystems and their responses to climate change , 1998 .

[18]  Leif T. Jensen,et al.  A comparison of the performance of nine soil organic matter models using datasets from seven long-term experiments , 1997 .

[19]  Daniel Rodriguez,et al.  LINGRA-CC : a sink-source model to simulate the impact of climate change and management on grassland productivity , 1999 .

[20]  T. L. Thurow,et al.  Comprehensive evaluation of the improved SPUR model (SPUR-91) , 1996 .

[21]  J. Amthor.  Terrestrial higher‐plant response to increasing atmospheric [CO2] in relation to the global carbon cycle , 1995 .

[22]  M. Cannell,et al.  Temperate Grassland Responses to Climate Change: an Analysis using the Hurley Pasture Model , 1997 .

[23]  Stephen P. Long,et al.  Modification of the response of photosynthetic productivity to rising temperature by atmospheric CO2 concentrations: Has its importance been underestimated? , 1991 .

[24]  R. Leuning.  A critical appraisal of a combined stomatal‐photosynthesis model for C3 plants , 1995 .

[25]  J. H. M. Thornley,et al.  Nitrogen Relations in a Forest Plantation—Soil Organic Matter Ecosystem Model , 1992 .

[26]  I. Impens,et al.  Stomatal regulation in a changing climate: a field study using Free Air Temperature Increase (FATI) and Free Air CO2 Enrichment (FACE) , 1997 .

[27]  Sven Erik Jørgensen,et al.  Development of models able to account for changes in species composition , 1992 .

[28]  J. Thornley.  Grassland Dynamics: An Ecosystem Simulation Model , 1998 .

[29]  Benoit Gabrielle,et al.  Analysis and Field Evaluation of the Ceres Models Water Balance Component , 1995 .

[30]  Yiqi Luo,et al.  Integration of photosynthetic acclimation to CO2 at the whole‐plant level , 1998 .

[31]  D. Whitehead,et al.  Decomposing grass herbage as a source of ammonia in the atmosphere , 1989 .

[32]  J. Fuhrer,et al.  A pasture simulation model for dry matter production, and fluxes of carbon, nitrogen, water and energy , 1998 .

[33]  P. Jarvis,et al.  Do stomata respond to relative humidity , 1991 .

[34]  Gordon B. Bonan,et al.  A biophysical surface energy budget analysis of soil temperature in the boreal forests of interior Alaska , 1991 .

[35]  The effect of nitrogenous fertilizer on the photosynthesis of leaves of a ryegrass sward , 1985 .

[36]  Arana,et al.  Progress in Photosynthesis Research , 1987, Springer Netherlands.

[37]  D. O. Hall,et al.  Response of Temperate and Tropical Grasslands to CO 2 and Climate Change , 1995 .

[38]  R. Grant.  Dynamic Simulation of Phase Changes in Snowpacks and Soils , 1992 .

[39]  Steven W. Running,et al.  Modeled responses of terrestrial ecosystems to elevated atmospheric CO2: a comparison of simulations by the biogeochemistry models of the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) , 1998, Oecologia.