Publications
lastest publication
Pleistocene megafaunal collapse, novel plant communities, and enhanced fire regimes in North America
Jacquelyn L. Gill1,2, John W. Williams1,2, Stephen T. Jackson3, Katherine B. Lininger1, Guy S. Robinson4
1Department of Geography, University of Wisconsin, Madison, WI 53706, USA. 2Center for Climatic Research, University of Wisconsin, Madison, WI 53706, USA. 3Department of Botany, University of Wyoming, Laramie, WY 92071, USA. 4Department of Natural Science, Lincoln Center Campus, Fordham University, New York, NY, USA.
Abstract:
Although the North American megafaunal extinctions and the formation of novel plant communities are well-known features of the last deglaciation, the causal relationships between these phenomena are unclear. Using the dung fungus Sporormiella and other paleoecological proxies from Appleman Lake, Indiana, and several New York sites, we established that the megafaunal decline closely preceded enhanced fire regimes and the development of plant communities that have no modern analogs. The loss of keystone megaherbivores may thus have altered ecosystem structure and function by the release of palatable hardwoods from herbivory pressure and by fuel accumulation. Megafaunal populations collapsed from 14,800 to 13,000 years ago, before the final extinctions and during the Bølling-Allerød warm period. Human impacts remain plausible, but the decline predates Younger Drays cooling and the extraterrestrial impact proposed to have occurred 12,900 years ago.
link to the paper (subscription required), read the accompanying Perspectives article by Christopher Johnson (subscription required), and listen to the podcast!
in press
Williams, J.W., Shuman, B., Bartlein, P.J., Diffenbaugh, N.S. and Webb, T., III (in press) Rapid, time-transgressive, and variable responses to early-Holocene midcontinental drying in North America. Geology.
Tabor, K., and Williams, J. W. (in press). Globally downscaled climate projections for assessing the conservation impacts of climate change. Ecological Applications.
Gonzales, L.M., Williams, J.W., and Grimm, E.C. (in press). Expanded response surfaces: A new method to reconstruct paleoclimates from fossil pollen assemblages that lack modern analogues. Quaternary Science Reviews.
2009
Gill, J. L., Williams, J. W., Jackson, S. T., Lininger, K., and Robinson, G. S. (2009). Pleistocene megafaunal collapse preceded novel plant communities and enhanced fire regimes. Science 326: 1100-1103. (PDF (subscription required); see the accompanying Perspectives article by Christopher Johnson)
Richardson, D. M., J. J. Hellmann, J. McLachlan, D. F. Sax, M. W. Schwartz, J. Brennan, P. Gonzalez, T. root, O. Sala, S. H. Schneider, D. Ashe, A. Camacho, J. R. Clark, R. Early, J. Etterson, D. Fielder, J.L. Gill, B. A. Minteer, S. Polasky, H. Safford, A. Thompson, and M. Vellend. (2009). Multidimensional evaluation of managed relocation. Proceedings of the National Academy of Sciences. 106: 9721-9724
Lorenz, D. J., Vavrus, S. J., Vimont, D. J., Williams, J. W., Notaro, M., Young, J. A., DeWeaver, E. T., and Hopkins, E. J. (2009). Wisconsin's changing climate: temperature. Understanding Climate Change: Climate Variability, Predictability, and Change in the Midwestern United States. Edited by S. C. Pryor. Indiana University Press, Bloomington, IN, pp. 76-87.
Lorenz, D. J., Vavrus, S. J., Vimont, D. J., Williams, J. W., Notaro, M., Young, J. A., DeWeaver, E. T., and Hopkins, E. J. (2009). Wisconsin's changing climate: hydrologic cycle. Understanding Climate Change: Climate Variability, Predictability, and Change in the Midwestern United States. Edited by S. C. Pryor. Indiana University Press, Bloomington, IN, pp. 135-144.
Williams, J. W. (2009) Quaternary Vegetation Distributions. Encyclopedia of Paleoclimatology and Ancient Environments. Edited by V. Gornitz. Kluwer Academic Publishers. (pre-print).
Williams, J.W, Shuman, B., and Bartlein, P.J. (2009) Rapid responses of the prairie-forest ecotone to early Holocene aridity in mid-continental North America. Global and Planetary Change. 66: 195-207 (PDF)
Gonzales, L.M., Grimm, E.C. (2009) Synchronization of late-glacial vegetation changes at Crystal Lake, Illinois, USA with the North Atlantic Event Stratigraphy. Quaternary Research. 72: 234-245 (PDF)
Gonzales, L.M., Grimm, E.C., Williams, J.W, and Nordheim, E.V. (2009) A modern plant-climate research dataset for modeling eastern North American plant taxa. Grana. 48: 1-18.
2008
Gonzales, L.M., Williams, J.W, and Kaplan, J.O. (2008) Variations in leaf area index in northern and eastern North America over the past 21 000 years: A data-model comparison. Quaternary Science Reviews. 27: 1453-1466. (PDF)
Williams, J.W., Gonzales, L.M., Kaplan, J.O., (2008) Leaf area index for northern and eastern North America at the Last Glacial Maximum: a data-model comparison. Global Ecology and Biogeography. 17: 122-134. (PDF (subscription required))
Williams, J. W., and Shuman, B. (2008). Obtaining accurate and precise environmental reconstructions from the modern analog technique and North American surface pollen dataset. Quaternary Science Reviews 27: 669-687.(PDF)
Cook, E.R. Bartlein, P. J., Diffenbaugh, N. S., Seager, R., Shuman, B., Webb, R. S., Williams, J. W., Woodhouse, C. A. (2008) Hydrological variability and change, Abrupt Climate Change, A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research, Washington, DC.
Minckley, T.A. Bartlein, P. J., Whitlock, C., Shuman, B. N., Williams, J. W., Davis, O. K. (2008) Associations among modern pollen, vegetation, and climate in western North America. Quaternary Science Reviews, 27: 1939-2094.
2007
Williams, J. W. and Jackson, S. T. (2007) Novel Climates, No-Analog Plant Communities, and Ecological Surprises: Past and Future. Frontiers in Ecology and Evolution 5: 475-482. doi:10.1890/070037. (PDF)
Williams, J. W., Jackson, S. T., Kutzbach, J. E. (2007) Projected distributions of novel and disappearing climates by 2100AD. Proceedings of the National Academy of Sciences 104: 5738-5742. (PDF) (Suppl. Figures) (Suppl. Tables) (Powerpoint Slides)
2006
Williams, J. W., B. Shuman, P. J. Bartlein, J. Whitmore, K. Gajewski, M. Sawada, T. Minckley, S. Shafer, A. E. Viau, T. Webb, III, P. M. Anderson, L. B. Brubaker, C. Whitlock, and O. K. Davis. (2006). An Atlas of Pollen-Vegetation-Climate Relationships for the United States and Canada. American Association of Stratigraphic Palynologists Foundation, Dallas, TX, 293p.
Diffenbaugh, N. S., Ashfaq, M., Shuman, B., Williams, J. W., Bartlein, P. J. (2006). Summer aridity in the United States: Response to Mid-Holocene changes in insolation and sea surface temperature. Geophysical Research Letters 33, DOI: 10.1029/2006GL028012 (PDF)
Seabloom, E. W., Williams, J. W., Slayback, D., Stoms, D. M., Viers, J. H., Dobson, A. P. (2006) Human impacts, plant invasion, and imperiled species in California. Ecological Applications 16: 1338-1350.
Notaro, M., Liu, Z., and Williams, J. W. (2006) Observed vegetation-climate feedbacks in the United States. Journal of Climate 19: 763-786. (PDF)
2005
Kutzbach, J. E., Williams, J. W., and Vavrus, S. J. (2005) Simulated 21st century changes in regional water balance of the Great Lakes region and links to changes in global temperature and poleward moisture transport. Geophysical Research Letters 32, doi:10.1029/2005GL023506. (PDF)
Jennings, M. D., Williams, J. W., Stromberg, M. R. (2005) Diversity and productivity across plant communities of the inland northwest, USA. Oecologia 143/144: 607-618. (PDF)
Williams, J. W., Seabloom, E. W., Slayback, D., Stoms, D. M., Viers, J. H. (2005) Anthropogenic impacts upon plant species richness and net primary productivity in California. Ecology Letters 8: 127-137. (PDF)
Whitmore, J., Gajewski, K., Sawada, M., Williams, J. W., Shuman, B., Bartlein, P. J., Minckley, T., Viau, A. E., Webb, T., III, Anderson, P. M., and Brubaker, L. B. (2005). North American and Greenland modern pollen data for multi-scale paleoecological and paleoclimatic applications. Quaternary Science Reviews 24, 1828-1848. (PDF)
Jennings, M. D., Williams, J. W., Stromberg, M. R. (2005) Diversity and productivity across plant communities of the inland northwest, USA. Oecologia 143/144: 607-618. (PDF)
2004
Jackson, S. T. and Williams, J. W. (2004) Modern analogs in Quaternary paleoecology: Here today, gone yesterday, gone tomorrow? Annual Review of Earth and Planetary Sciences 32: 495-537. (PDF)
Webb, T., Shuman, B. N., Williams, J. W. (2004) Climatically forced vegetation dynamics in eastern North America during the late Quaternary period. The Quaternary Period in the United States. Edited by Gillespie, A. R., Porter, S. C., Atwater, B. F. Elsevier, pp. 459-478. (PDF)
Williams, J. W., Shuman, B. N., Webb, T., III, Bartlein, P. J., Leduc, P.(2004) Quaternary vegetation dynamics in North America: Scaling from taxa to biomes. Ecological Monographs 74: 309-334. (Abstract and Figure PDFs) (PDF)
Chalcraft, D. R., Williams, J. W., Smith, M. D., Willig, M. R. (2004) Scale dependence in the relationship between diversity and productivity: assessing the role of spatial and temporal turnover. Ecology 85: 2701-2708. (PDF)
2003
Gavin, D. G., Oswald, W. W., Wahl, E. R., Williams, J. W. (2003) A statistical approach to evaluating distance metrics and analog assignments for pollen records. Quaternary Research 60: 356-367. (Abstract) (PDF)
Williams, J. W. and Jackson, S. T. (2003) Palynological and AVHRR observations of modern vegetational gradients in eastern North America. The Holocene 13: 485-497. (Abstract) (PDF)
Williams, J. W. (2003) Needleleaved and broadleaved tree cover distributions in North America since the Last Glacial Maximum. Global and Planetary Change 35: 1-23. (Abstract and Figure PDFs) (PDF)
2002
Williams, J. W., Post, D. M., Cwynar, L. C., Lotter, A. F., Levesque, A. J. (2002) Rapid vegetation responses to past climate change. Geology 30: 971-974. (Abstract) (PDF)
Shuman, B. N., Webb III, T., Bartlein, P. J., Williams, J. W. (2002) The anatomy of a climatic oscillation: Vegetation change in eastern North America during the Younger Dryas chronozone. Quaternary Science Reviews 21: 1777-1791. (PDF)
2001
Williams, J. W., Shuman, B. N., Webb III, T. (2001) No-analog conditions and rates of change in the climate and vegetation of eastern North America. Ecology 82: 3346-3362. (Abstract and Figure PDFs) (PDF)
2000
Williams, J. W., Webb III, T., Richard, P. J. H., and Newby, P. (2000) Late Quaternary biomes of Canada and the eastern United States. Journal of Biogeography 27: 585-607. (Abstract) (PDF)
Edwards, M. E., Anderson, P. M., Brubaker, L. B., Ager, T., Andreev, A. A., Bigelow, N. H., Cwynar, L. C., Eisner, W. R., Harrison, S. P., Hu, F.-S., Jolly, D., Lozhkin, A. V., McDonald, G. M., Mock, C. J., Ritchie, J. C., Sher, A. V., Spear, R. W., Williams, J. W., and Yu., G. (2000) Pollen-based biomes for Beringia 18,000, 6000, and 0 14C yr. B.P. Journal of Biogeography 27: 521-554.
Williams, J. W., Webb III, T., Shuman, B. N., and 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 53: 402-404. (PDF)
Williams, J. W., Bartlein, P. J., and Webb III, T. (2000) Data-model comparisons for eastern North America - inferred biomes and climate values from pollen data. Proceedings of the Third Paleoclimate Modeling Intercomparison Project Workshop, Oct. 4-8, 1999. Montreal, Canada. Edited by P. Braconnot. WCRP-111, WMO/TD-No. 1007. (PDF)
Jackson, S. T., Webb, R. S., Anderson, K. H., Overpeck, J. T., Webb III, T., Williams, J. W., and Hansen, B. C. S. (2000) Vegetation and environment in eastern North America during the last glacial maximum. Quaternary Science Reviews 19: 489-508. (PDF)
pre-2000
Williams, J. W., Summers, R., and Webb III, T. (1998) Applying plant functional types to construct biome maps from eastern North American pollen data: comparisons with model results. Quaternary Science Reviews 17: 607-627. (Abstract) (PDF)
Leduc, P. L., Williams, J. W., and Webb III, T. (1998) Programs for site selection, tabular display, and interpolation of data from Paradox-based pollen databases. INQUA Newsletter 17.
Williams, J. W. (1995) Factors controlling the formation of fossiliferous beds in the Devonian Columbus limestone at Marblehead Quarry, Marblehead, Ohio. Ohio Journal of Sciences 95: 325-330.
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