Running Steven W.

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Steven W.

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  • Article
    China's terrestrial carbon balance : contributions from multiple global change factors
    (American Geophysical Union, 2011-03-31) Tian, Hanqin ; Melillo, Jerry M. ; Lu, Chaoqun ; Kicklighter, David W. ; Liu, Mingliang ; Ren, Wei ; Xu, Xiaofeng ; Chen, Guangsheng ; Zhang, Chi ; Pan, Shufen ; Liu, Jiyuan ; Running, Steven W.
    The magnitude, spatial, and temporal patterns of the terrestrial carbon sink and the underlying mechanisms remain uncertain and need to be investigated. China is important in determining the global carbon balance in terms of both carbon emission and carbon uptake. Of particular importance to climate-change policy and carbon management is the ability to evaluate the relative contributions of multiple environmental factors to net carbon source and sink in China's terrestrial ecosystems. Here the effects of multiple environmental factors (climate, atmospheric CO2, ozone pollution, nitrogen deposition, nitrogen fertilizer application, and land cover/land use change) on net carbon balance in terrestrial ecosystems of China for the period 1961–2005 were modeled with newly developed, detailed historical information of these changes. For this period, results from two models indicated a mean land sink of 0.21 Pg C per year, with a multimodel range from 0.18 to 0.24 Pg C per year. The models' results are consistent with field observations and national inventory data and provide insights into the biogeochemical mechanisms responsible for the carbon sink in China's land ecosystems. In the simulations, nitrogen deposition and fertilizer applications together accounted for 61 percent of the net carbon storage in China's land ecosystems in recent decades, with atmospheric CO2 increases and land use also functioning to stimulate carbon storage. The size of the modeled carbon sink over the period 1961–2005 was reduced by both ozone pollution and climate change. The modeled carbon sink in response to per unit nitrogen deposition shows a leveling off or a decline in some areas in recent years, although the nitrogen input levels have continued to increase.
  • Article
    Aggregate measures of ecosystem services : can we take the pulse of nature?
    (Ecological Society of America, 2005-02) Meyerson, Laura A. ; Baron, Jill ; Melillo, Jerry M. ; Naiman, Robert J. ; O'Malley, Robin I. ; Orians, Gordon ; Palmer, Margaret A. ; Pfaff, Alexander S. P. ; Running, Steven W. ; Sala, Osvaldo E.
    National scale aggregate indicators of ecosystem services are useful for stimulating and supporting a broad public discussion about trends in the provision of these services. There are important considerations involved in producing an aggregate indicator, including whether the scientific and technological capacity exists, how to address varying perceptions of the societal importance of different services, and how to communicate information about these services to both decision makers and the general public. Although the challenges are formidable, they are not insurmountable. Quantification of ecosystem services and dissemination of information to decision makers and the public is critical for the responsible and sustainable management of natural resources.
  • Preprint
    Reconciling carbon-cycle concepts, terminology, and methods
    ( 2006-01-06) Chapin, F. Stuart ; Woodwell, G. M. ; Randerson, James T. ; Rastetter, Edward B. ; Lovett, G. M. ; Baldocchi, Dennis D. ; Clark, D. A. ; Harmon, Mark E. ; Schimel, David S. ; Valentini, R. ; Wirth, C. ; Aber, J. D. ; Cole, Jonathan J. ; Goulden, Michael L. ; Harden, J. W. ; Heimann, M. ; Howarth, Robert W. ; Matson, P. A. ; McGuire, A. David ; Melillo, Jerry M. ; Mooney, H. A. ; Neff, Jason C. ; Houghton, Richard A. ; Pace, Michael L. ; Ryan, M. G. ; Running, Steven W. ; Sala, Osvaldo E. ; Schlesinger, William H. ; Schulze, E.-D.
    Recent patterns and projections of climatic change have focused increased scientific and public attention on patterns of carbon (C) cycling and its controls, particularly the factors that determine whether an ecosystem is a net source or sink of atmospheric CO2. Net ecosystem production (NEP), a central concept in C-cycling research, has been used to represent two different concepts by C-cycling scientists. We propose that NEP be restricted to just one of its two original definitions—the imbalance between gross primary production (GPP) and ecosystem respiration (ER), and that a new term—net ecosystem carbon balance (NECB)—be applied to the net rate of C accumulation in (or loss from; negative sign) ecosystems. NECB differs from NEP when C fluxes other than C fixation and respiration occur or when inorganic C enters or leaves in dissolved form. These fluxes include leaching loss or lateral transfer of C from the ecosystem; emission of volatile organic C, methane, and carbon monoxide; and soot and CO2 from fire. C fluxes in addition to NEP are particularly important determinants of NECB over long time scales. However, even over short time scales, they are important in ecosystems such as streams, estuaries, wetlands, and cities. Recent technological advances have led to a diversity of approaches to measuring C fluxes at different temporal and spatial scales. These approaches frequently capture different components of NEP or NECB and can therefore be compared across scales only by carefully specifying the fluxes included in the measurements. By explicitly identifying the fluxes that comprise NECB and other components of the C cycle, such as net ecosystem exchange (NEE) and net biome production (NBP), we provide a less ambiguous framework for understanding and communicating recent changes in the global C cycle. Key words: Net ecosystem production, net ecosystem carbon balance, gross primary production, ecosystem respiration, autotrophic respiration, heterotrophic respiration, net ecosystem exchange, net biome production, net primary production.