NCEAS Project 2201

Integrating satellite and pollen data with biogeochemical modelling to reconstruct long-term trends in the productivity and carbon sequestration of terrestrial ecosystems

  • John W. Williams

ActivityDatesFurther Information
Postdoctoral Fellow20th September 1999—19th September 2001Participant List  
Working Group19th—22nd February 2000Participant List  

Abstract
The annual net primary productivity (NPP) of terrestrial ecosystems directly regulates the amount of CO2 in the atmosphere (Huntet al., 1996; IPCC, 1995). The advent of satellite-based remote sensing within the past two decades has enabled us to assess global patterns of phenology, NPP, and carbon sequestration. However, the satellite record is far too short to determine centennial or longer trends. Therefore we must look to new avenues if we are to place the 20-yearrecord of satellite-measured terrestrial NPP within the context of the steady adjustments of plant populations in response to long-term changes in climate and atmospheric CO2. Fossil pollen data provide continuous records spanning millennia that demonstrate the large shifts in the ranges and abundances in plant populations that have occurred since the last glacial maximum (LGM), 21,000 years ago. Maps of modern pollen abundances clearly show that the pollen percentage of a plant taxon reflects its abundance on the landscape. Although there have been several attempts to estimate the past amounts of carbon stored in the terrestrial biosphere, most of these attempts have not made use of process-based biogeochemistry models and their estimates have ranged widely.

I suggest a pioneering approach to determine the past productivity and carbon sequestration of the terrestrial biosphere. I plan to synthesize the information contained in the pollen and satellite vegetation records to estimate the leaf area index (LAI) of past ecosystems, then use the inferred LAI, maps of past land cover already published (Williams et al., 1998; Williams et al., in press), and paleoclimatic simulations to run BIOME-BGC, a sophisticated biogeochemistry model that predicts NPP and carbon sequestration by directly simulating the processes of photosynthesis, respiration, and carbon allocation (Running and Hunt, 1993). The goal is to produce maps of LAI, NPP, and carbon storage for key time periods in the past. These maps will be highly relevant to those seeking to understand the present-day interactions between vegetation productivity, climate, and atmospheric CO2, and the potential for the system to change.

TypeProducts of NCEAS Research
Journal Article Gavin, D. G.; Oswald, W. W.; Wahl, E. R.; Williams, John W. 2003. A statistical approach to evaluating distance metrics and analog assignments for pollen records. Quaternary Research. Vol: 60(3). Pages 356-367.
Journal Article Shuman, B. N.; Webb, Thompson III; Bartlein, P. J.; Williams, John W. 2002. The anatomy of a climatic oscillation: Vegetation change in eastern North America during the Younger Dryas chronozone. Quaternary Science Reviews. Vol: 21. Pages 1777-1791.
Book Chapter Webb, Thompson III; Shuman, B. N.; Williams, John W. 2003. Climatically forced vegetation dynamics in North America during the Late-Quaternary. Edited by Gillespie, A. R.; Porter, S. C.; Atwater, B. F.. The Quaternary Period in the United States. Elsevier. Boston. Pages 459-478.
Presentations Williams, John W.; Bartlein, P. J.; Webb, Thompson III. 1999. BIOME1 and BIOME3 simulations of Mid-Holocene vegetation: Testing the models. American Geophysical Union Fall Meeting. San Francisco, CA.
Presentations Williams, John W. 1999. Climate and BIOME-model simulations for the mid-Holocene. Testing Earth System Models with Paleoenvironmental Observations Workshop. Boulder, CO.
Presentations Williams, John W.; Bartlein, P. J.; Webb, Thompson III. 1999. Data-model comparisons for eastern North America: Inferred biomes and climate values from pollen data. 3rd Paleoclimate Modeling Intercomparison Project Workshop. Montreal, Canada.
Journal Article Williams, John W. 2000. Book Review: Bonnicksen, T. M. 2000. America's ancient forests: From the Ice Age to the Age of Discovery. Wiley, New York. Conservation Ecology. Vol: 4(2). Pages 2. (Online version)
Report or White Paper Williams, John W.; Bartlein, P. J.; Webb, Thompson III. 2000. Data-model comparisons for eastern North America - Inferred biomes and climate values from pollen data. Proceedings of the Third PMIP Workshop, 4-8 October 1999, Montreal, Canada. Pages 77-86.
Journal Article Williams, John W.; Webb, Thompson III; Shuman, B. N.; Bartlein, P. J. 2000. Do low CO2 concentrations affect pollen-based reconstructions of LGM climates? A response to Physiological significance of low atmospheric CO2 for plant-climate interactions by Cowling and Sykes. Quaternary Research. Vol: 53. Pages 402-404.
Presentations Williams, John W.; Jackson, Stephen. 2000. Fossil pollen records and AVHRR: Complementary sensors of the vegetation. Ecological Society of America Annual Meeting. Snowbird, UT.
Presentations Williams, John W. 2000. Land cover change in boreal and eastern North America since the last glacial maximum. American Geophysical Union Fall Meeting. San Francisco, CA.
Presentations Williams, John W.; Shuman, B. N.; Webb, Thompson III. 2000. No-Analog biomes and climate in eastern North America. American Geophysical Union Spring Meeting. Washington DC.
Presentations Williams, John W. 2000. Vegetation dynamics, climate change, and no-analog plant communities in eastern North America during the late Quaternary. Department of Geophysical Sciences, University of Chicago. Chicago, IL.
Presentations Williams, John W. 2000. Vegetation responses to climate change in North America since the last ice age. Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara. Santa Barbara, CA.
Journal Article Williams, John W.; Shuman, B. N.; Webb, Thompson III. 2001. Dissimilarity analyses of late-Quaternary vegetation and climate in eastern North America. Ecology. Vol: 82. Pages 3346-3362.
Presentations Williams, John W.; Post, David M.; Cwynar, L. C.; Lotter, A. F.; Levesque, A. J. 2001. Fast vegetational responses to late-glacial climate change. American Geophysical Union Fall Meeting. San Francisco, CA.
Presentations Williams, John W. 2001. Late-Quaternary land cover change in boreal and eastern North America. Ecological Society of America Annual Meeting. Madison, WI.
Presentations Williams, John W. 2001. Needleleaved and broadleaved tree cover reconstructions inferred from the iterated analog technique. Testing Earth System Models with Paleoenvironmental Observations. Boulder, CO.
Presentations Williams, John W.; Hunt, Earle Raymond; Jackson, Stephen. 2002. Integrating AVHRR and paleoecological data to reconstruct past variations in tree cover and the terrestrial carbon cycle. American Quaternary Association Biennial Meeting. Anchorage, AK.
Journal Article Williams, John W.; Post, David M.; Cwynar, L. C.; Lotter, A. F.; Levesque, A. J. 2002. Rapid and widespread vegetation responses to past climate change in the North Atlantic Region. Geology. Vol: 30. Pages 971-974.
Presentations Williams, John W. 2002. Vegetation-atmosphere interactions during the late Quaternary: Current advances and future directions. American Geophysical Union Fall Meeting. San Francisco, CA.
Presentations Williams, John W.; Shuman, B. N.; Webb, Thompson III; Bartlein, P. J. 2003. North American vegetation and climates from 21,000 years ago to present: Useful data sets for testing earth system models. International Union for Quaternary Research (INQUA). Reno, NV.
Journal Article Williams, John W.; Jackson, Stephen. 2003. Palynological and AVHRR observations of modern vegetational gradients in eastern North America. Holocene. Vol: 13(4). Pages 485-497.
Presentations Williams, John W.; Jackson, Stephen. 2003. Quantitative reconstructions of Late Quaternary tree cover from modern pollen-AVHRR calibrations. International Union for Quaternary Research (INQUA). Reno, NV.
Journal Article Williams, John W. 2003. Variations in tree cover in North America since the last glacial maximum. Global Planetary Change. Vol: 35. Pages 1-23.
Journal Article Williams, John W.; Shuman, B. N.; Webb, Thompson III; Bartlein, P. J.; Leduc, P. 2004. Late-Quaternary vegetation dynamics in North America: Scaling from taxa to biomes. Ecological Monographs. Vol: 74. Pages 309-334.
Presentations Williams, John W.; Post, David M.; Cwynar, L. C.; Lotter, A. F.; Levesque, A. J. Rapid and widespread vegetation responses to late-glacial climate change in the North Atlantic region. Ecological Society of America Annual Meeting. Tucson, AZ.