Simulation model for the effects of climate change on temperate grassland ecosystems

Hunt, H. W.; Trlica, M. J.; Redente, Edward F.; Moore, John C.; Detling, James K.; Kittel, T.G.F.; Walter, David; Fowler, Melanie; Klein, Donald A.; Elliott, E. T.

doi:10.1016/0304-3800(91)90157-v

Cited by 126 publications

(71 citation statements)

References 61 publications

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“…A change in C dynamics is important because grassland soils are important C sinks (see IPCC 2000). CC may cause a net loss of soil C, as opposed to an increase in C sequestration due to the direct effect of elevated CO 2 (Hunt et al 1991, Ojima et al 1993, Parton et al 1994. At present, the outcome of the interaction between these factors is uncertain.…”

Section: Introductionmentioning

confidence: 99%

Pasture responses to elevated temperature and doubled CO2 concentration: assessing the spatial pattern across an alpine landscape

Riedo¹,

Gyalistras²,

Fuhrer³

2001

Clim. Res.

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Climatic change and increasing atmospheric CO 2 concentration are expected to have significant effects on grassland ecosystems, but the magnitude of the responses may vary strongly across complex landscapes. A combination of the mechanistic pasture simulation model PaSim, statistical interpolation of climate parameters, and stochastic weather generation was used to examine the range and spatial distribution of the long-term responses of grazed grassland ecosystems to step changes in temperature and CO 2 across the 250 km 2 alpine Davos/Dischma region in Switzerland. 750 sites were considered, covering an altitude range from 1500 to 2700 m above sea level. PaSim was driven with sitespecific hourly weather data, georeferenced input data for topography, and soil and vegetation characteristics. A seasonally uniform temperature increase by 2°C raised the mean evapotranspiration (ET ) from about 200 to 300 mm yr -1 , and net primary production (NPP) from about 0.2 to 0.3 kg C m -2 yr -1 . Doubling CO 2 to 700 ppm partially offset the increase in ET, but caused an additional increase in NPP. The effects of the different scenarios on the simulated mean labile soil organic carbon content (C fast ) were small, and on the order of +1% due to increased temperature and + 5% due to increased CO 2 . Largest absolute changes in ET were obtained for sites with ample precipitation, whereas relative changes correlated best with altitude. Largest absolute changes in NPP were obtained for the most productive lower sites, whereas at higher sites absolute changes became small, but relative changes were again largest. Most pronounced increases in C fast of around 10% (equivalent to about 0.3 kg C m -2 ) resulted from the combined temperature and CO 2 increase and occurred mainly at the higher elevation sites. For all parameters examined the variability of absolute system responses across sites was generally larger than the magnitude of the mean changes resulting from any scenario. Statistical analysis of the relationship between a small set of site-specific input parameters and model outputs revealed that the most important factors determining absolute system responses under all scenarios were altitude and aspect for ET, temperature for NPP, and soil texture (i.e. clay fraction) for C fast . Absolute and relative changes due to the assumed changes in CO 2 and/or temperature depended less clearly on these factors, in particular for C fast . These results show that the interaction of the effects of elevated CO 2 and increased temperature with local site conditions causes a spatially inhomogeneous distribution of grassland responses in a topographically complex landscape, but that absolute system responses for a given temperature and CO 2 regime can be explained with very high accuracy by a small number of environmental variables.

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Section: Introductionmentioning

confidence: 99%

Pasture responses to elevated temperature and doubled CO2 concentration: assessing the spatial pattern across an alpine landscape

Riedo¹,

Gyalistras²,

Fuhrer³

2001

Clim. Res.

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“…3). Similarly, simulations with the grassland ecosystem model (GEM) predicted increased productivity and C storage in plant residue and SOM for temperate grasslands in response to doubled CO 2 (Hunt et al 1991). Soil organic carbon content in TiPC scenario was less than that of TP, which reflected that the negative of increasing temperature was more than the positive of increasing CO 2 .…”

Section: Resultsmentioning

confidence: 95%

Soil organic carbon budget and fertility variation of black soils in Northeast China

Han

Gao

et al. 2006

Ecological Research

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Black soils in Northeast China are characteristic of high soil organic carbon (SOC) density and were strongly influenced by human activities. Therefore, any change in SOC pool of these soils would not only impact the regional and global carbon cycle, but also affect the release and immobilization of nutrients. In this study, we reviewed the research progress on SOC storage, budget, variation, and fertility under different scenarios. The results showed that the organic carbon storage of black soils was 646.2 TgC and the most potential sequestration was 2887.8 g m À2 . According to the SOC budget, the net carbon emission of black soils was 1.3 TgC year À1 under present soil management system. The simulation of CENTURY model showed that future climate change and elevated CO 2 concentration, especially the increase of precipitation, would increase SOC content. Furthermore, fertilization and cropping sequence obviously influenced SOC content, composition, and allocation among different soil particles. Long-term input of organic materials such as manure and straw renewed original SOC, improved soil structure and increased SOC accumulation. Besides, soil erosion preferred to transport soil particles with low density and fine size, decreased recalcitrant SOC fractions at erosion sites and increased activities of soil microorganism at deposition sites. After natural grasslands were converted into croplands, obvious variation of soil chemical nutrients, physical structure, and microbial activities had taken place in surface and subsurface soils, and represented a degrading trend to a certain degree. Our studies suggested that adopting optimal management such as conservation tillage in black soil region is an important approach to sequester atmospheric CO 2 and to slow greenhouse effects.

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“…The parameter s b represents a sort of permanent "wilting" point for soil microbial biomass. Although this parameter is either not considered explicitly (Gusman and Marino, 1999;Porporato et al, 2003) or assumed to be equal to the corresponding plant wilting point (Hunt et al, 1991), its role in soil nutrient dynamics is very important. In particular, its relationship with the plant wilting point, s w , that defines the level at which transpiration and passive nitrogen uptake are stopped, provides a way to account for the impact of water stress on the competition for nutrients between plants and soil microbial biomass (Kaye and Hart, 1997).…”

Section: )mentioning

confidence: 99%

“…The dependence of microbial activity on soil temperature is described by a quadratic relation (Ratkowsky et al, 1982;Katterer and Andrèn, 2001), with a minimum survival temperature for microbial biomass (about −5 • C, according to Hunt et al, 1991;Katterer and Andrèn, 2001) and an optimum temperature that, on account of the adaptation of microbial colonies to a specific site, can be taken as the maximum soil temperature measured in the field (Katterer and Andrèn, 2001). The inclusion of f t (T ) and s b are elements of novelty with respect to the previous version of the model .…”

Section: )mentioning

confidence: 99%

“…Various models have been proposed in the past to investigate these dynamics (e.g. Parton et al, 1988;Hunt et al, 1991;Gusman and Marino, 1999;Melillo et al, 1995;Benbi and Richter, 2002;Schimel and Weintraub, 2003;Schimel and Bennett, 2004, and references therein) resulting in a deeper understanding of soil biogeochemistry under a broad variety of climatic and ecological conditions.…”

Section: Introductionmentioning

confidence: 99%

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Soil nutrient cycles as a nonlinear dynamical system

Manzoni

Porporato

D’Odorico

et al. 2004

Nonlin. Processes Geophys.

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Abstract. An analytical model for the soil carbon and nitrogen cycles is studied from the dynamical system point of view. Its main nonlinearities and feedbacks are analyzed by considering the steady state solution under deterministic hydro-climatic conditions. It is shown that, changing hydroclimatic conditions, the system undergoes dynamical bifurcations, shifting from a stable focus to a stable node and back to a stable focus when going from dry, to well-watered, and then to saturated conditions, respectively. An alternative degenerate solution is also found in cases when the system can not sustain decomposition under steady external conditions. Different basins of attraction for "normal" and "degenerate" solutions are investigated as a function of the system initial conditions. Although preliminary and limited to the specific form of the model, the present analysis points out the importance of nonlinear dynamics in the soil nutrient cycles and their possible complex response to hydro-climatic forcing.

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Simulation model for the effects of climate change on temperate grassland ecosystems

Cited by 126 publications

References 61 publications

Pasture responses to elevated temperature and doubled CO2 concentration: assessing the spatial pattern across an alpine landscape

Pasture responses to elevated temperature and doubled CO2 concentration: assessing the spatial pattern across an alpine landscape

Soil organic carbon budget and fertility variation of black soils in Northeast China

Soil nutrient cycles as a nonlinear dynamical system

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