VEGETATION AND CLIMATE CHANGE IN EASTERN NORTH AMERICA SINCE THE LAST GLACIAL MAXIMUM

Response surfaces describing the empirical dependence of surface pollen percentages of 13 taxa on three standard climatic variables (mean July temperature, mean January temperature, and mean annual precipitation) in eastern North America were used to infer past climates from palynological data. Inferred climates at 3000-yr intervals from 18 000 years ago to the present, based on six taxa (spruce, birch, northern pines, oak, southern pines, and prairie forbs), were used to generate time series of simulated isopoll maps for these taxa and seven others (hickory, fir, beech, hemlock, elm, alder, and sedge). The simulations captured the essential features of the observed isopoll maps for both sets of taxa, including differences in migration patterns during the past 10 000 yr that have previously been attributed to differential migration lag. These results establish that the continental-scale vegetation patterns have responded to continuous changes in climate from the last glacial maximum to the present, with lags < 1500 yr. The inferred climatic changes include seasonality changes consistent with orbitally controlled changes in inso- lation, and shifts in temperature and moisture gradients that are consistent with modelled climatic interactions of the insolation changes with the shrinking Laurentide ice sheet. These results pose new ecological questions about the processes by which vegetated land- scapes approach dynamic equilibrium with their changing environment.

[1]  John F. Richards,et al.  The Cambridge Encyclopedia of Human Evolution.@@@The Earth as Transformed by Human Action: Global and Regional Changes in the Biosphere Over the Past 300 Years. , 1993 .

[2]  Brian Huntley,et al.  Climatic control of the distribution and abundance of beech (Fagus L.) in Europe and North America. , 1989 .

[3]  I. Prentice,et al.  Orbital variations, climate and paleoecology. , 1989, Trends in ecology & evolution.

[4]  S. Harrison Lake levels and climatic change in eastern North America , 1989 .

[5]  Brian Huntley,et al.  Migration: Species' Response to Climatic Variations Caused by Changes in the Earth's Orbit , 1989 .

[6]  W. Cleveland,et al.  Locally Weighted Regression: An Approach to Regression Analysis by Local Fitting , 1988 .

[7]  H. Lamb,et al.  Holocene pollen sequences as a record of competitive interactions among tree populations. , 1988, Trends in ecology & evolution.

[8]  S. Webb,et al.  Beech Range Extension and Vegetation History: Pollen Stratigraphy of Two Wisconsin Lakes. , 1987, Ecology.

[9]  H. Delcourt,et al.  Long-Term Forest Dynamics of the Temperate Zone , 1987, Ecological Studies.

[10]  J. Kutzbach Model simulations of the climatic patterns during the deglaciation of North America , 1987 .

[11]  K. Bennett The rate of spread and population increase of forest trees during the postglacial , 1986 .

[12]  J. Kutzbach,et al.  The Influence of Changing Orbital Parameters and Surface Boundary Conditions on Climate Simulations for the Past 18 000 Years , 1986 .

[13]  Patrick J. Bartlein,et al.  Climatic response surfaces from pollen data for some eastern North American taxa , 1986 .

[14]  P. White,et al.  The Ecology of Natural Disturbance and Patch Dynamics , 1986 .

[15]  Daniel B. Botkin,et al.  Sensitivity of Cool-Temperate Forests and their Fossil Pollen Record to Rapid Temperature Change , 1985, Quaternary Research.

[16]  J. Overpeck,et al.  Quantitative Interpretation of Fossil Pollen Spectra: Dissimilarity Coefficients and the Method of Modern Analogs , 1985, Quaternary Research.

[17]  T. Webb,,et al.  Computer-Aided Reconstruction of Late-Quaternary Landscape Dynamics , 1985 .

[18]  J. C. Ritchie,et al.  Past and Present Vegetation of the Far Northwest of Canada. , 1985 .

[19]  H. Shugart A Theory of Forest Dynamics , 1984 .

[20]  B. Huntley,et al.  An Atlas of Past and Present Pollen Maps for Europe , 1984 .

[21]  T. Webb,,et al.  Holocene Changes In the Vegetation of the Midwest , 1983 .

[22]  John Z. Imbrie,et al.  Modeling the Climatic Response to Orbital Variations , 1980, Science.

[23]  Iain Colin Prentice,et al.  Multidimensional scaling as a research tool in quaternary palynology: A review of theory and methods , 1980 .

[24]  M. B. Davis,et al.  Pleistocene biogeography of temperate deciduous forests , 1976 .

[25]  J. Iversen Problems of the Early Post-Glacial Forest Development in Denmark , 1960 .