Potential
Changes in the Distributions of Western North America Tree and Shrub Taxa under
Future Climate Scenarios
Sarah L. Shafer, Patrick J. Bartlein, and Robert S. Thompson (2001).
Ecosystems 4:200-215.
Abstract Preprint .pdf file (6.5MB)
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Figure 1. Maps of the three bioclimatic variables:me n temperature of the coldest month (top row),growing degree days (middle row),and moisture index (bottom row).The first panel in each row displays the bioclimatic variable derived from the modern observed 1951-1980 climate dataset.The following three panels in each row display the bioclimatic variable as calculated from each of the three future-climate scenario datasets. |
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Figure 2. Response surfaces for Tilia americana and Ulmus americana .Each row shows the observed distribution of the species (left panel), the simulated probability of occurrence estimated using the response surface for the species and observed modern climate (middle panel), and the simulated probability of occurrence displayed as nine two-dimensional slices (GDD by MTCO) through a three-dimensional climate space, arranged by moisture index value (right panel). All the grid points in North America are displayed in the right-hand panel: gray points represent grid cells where the species is simulated to be absent and green points (shaded by probability of occurrence) represent grid cells where the species is simulated to occur. |
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Figure 3. Estimated species occurrence simulated with observed modern climate, compared with observed range distributions for four species in North America. Gray indicates areas where the species is present and is simulated to be present by the response surface model; red indicates areas where the species is present but is simulated to be absent (under-prediction); and blue indicates where the species is absent but is simulated to be present (over-prediction). |
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Figures 4. Comparison of observed distributions with future simulated distributions for fifteen species in North America, using climate scenarios for 2090-2099 generated by the HADCM2, CGCM1, and CSIRO GCMs (left three columns). "No change" indicates where the species is observed at present and is simulated to occur under future climate conditions; "contraction" indicates where the species is observed at present but is simulated to be absent under future climate conditions; and "extension" indicates where the species is not observed at present but is simulated to occur under future climate conditions. Agreement among the future distributions of each species as simulated by the three GCM scenarios is displayed by showing for each grid point the number of models that simulate a species to be present or absent (right two columns). |
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Figures 5. Comparison of observed distributions with future simulated distributions for fifteen species in North America, using climate scenarios for 2090-2099 generated by the HADCM2, CGCM1, and CSIRO GCMs (left three columns). "No change" indicates where the species is observed at present and is simulated to occur under future climate conditions; "contraction" indicates where the species is observed at present but is simulated to be absent under future climate conditions; and "extension" indicates where the species is not observed at present but is simulated to occur under future climate conditions. Agreement among the future distributions of each species as simulated by the three GCM scenarios is displayed by showing for each grid point the number of models that simulate a species to be present or absent (right two columns). |
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Figures 6. Comparison of observed distributions with future simulated distributions for fifteen species in North America, using climate scenarios for 2090-2099 generated by the HADCM2, CGCM1, and CSIRO GCMs (left three columns). "No change" indicates where the species is observed at present and is simulated to occur under future climate conditions; "contraction" indicates where the species is observed at present but is simulated to be absent under future climate conditions; and "extension" indicates where the species is not observed at present but is simulated to occur under future climate conditions. Agreement among the future distributions of each species as simulated by the three GCM scenarios is displayed by showing for each grid point the number of models that simulate a species to be present or absent (right two columns). |