Atlas of Relations Between Climatic Parameters and Distributions of Important Trees and Shrubs in North America—Revisions for all Taxa from the United States and Canada and New Taxa from the Western United States

Abstract

This is the seventh volume in an atlas series that explores the relations between the geographic distributions of woody plant species and climatic variables in North America. A 25-kilometer (km) equal-area grid of modern climatic and bioclimatic variables was constructed from weather data. The geographic distributions of selected tree and shrub species were digitized, and the presence or absence of each species was determined for each point on the 25-km grid, thus providing a basis for comparing climatic data and species' distributions. The relations between climate and plant distributions are presented in graphical and tabular form. The results of this effort are intended primarily for use in biogeographic, ecologic, paleoclimatic, and global-change research.

This volume of the atlas provides numerous changes, updates, and enhancements from previous volumes. Its geographic coverage is now restricted to Canada and the continental United States, and the source and time period of the climatic data have changed. New variables were added, including monthly values for temperature and precipitation, and measures of interannual variability. The distribution maps for all previously published species were redigitized, some distribution maps were revised, and 148 new species were added from the arid and semiarid western United States. The graphical displays were expanded to illustrate the new climatic variables, and the data tables were modified to provide more detail on the population distributions of plant taxa relative to climatic variables.

Abbreviations and Definitions

INTRODUCTION
Climatic Data
Original Source Data and Interpolation onto the 25-Kilometer CANUSA Grid
Correlations Among Climatic Variables
Comparison of Previous and Current Climatologies
Climatic Variables—Geography, Time Scales, and Population Distributions
Plant Distributions
Taxonomy and Nomenclature
Species Excluded from This Volume
Species Included in This Volume
Species with Redigitized Distribution Maps
Remapped Distributions of Species
Effects of Revising Distribution Maps
New Species
Characteristics of the Plant Distribution Data
Displays of Geographic Distributions and Climatic Relations
Metadata and Distribution Maps
Relations Between Single Climatic Variables and Species' Distributions
Bivariate Relations Between Climatic Variables and Species' Distributions
Multivariate Relations Between Climatic Variables and the Distributions of Species
Monthly Temperature and Precipitation
Tables of Relations of Plant Distributions to Single Climatic Variables
Seasonal Precipitation and Distribution of Southwestern United States Species
Climatic Variables and Plant Distributions
Acknowledgments
References Cited

Figures Accompanying Text

Figure 1. Maps and histograms of elevation, World Wildlife Fund (WWF) ecoregions, and bioclimatic and annual climatic variables for Canada and the continental United States, including Alaska.
Figure 2. Climatic data used in this atlas compared with the data used for an earlier volume of U.S. Geological Survey Professional Paper 1650.
Figure 3. Maps and histograms of monthly temperatures for Canada and the continental United States.
Figure 4. Maps and histograms of the standard deviations of monthly temperatures for Canada and the continental United States.
Figure 5. Maps and histograms of the amounts of monthly precipitation for Canada and the continental United States.
Figure 6. Maps and histograms of the coefficients of variation for monthly precipitation for Canada and the continental United States.
Figure 7. Maps and histograms of monthly precipitation for Canada and the continental United States expressed as percentages of annual precipitation.
Figure 8. Maps and histograms of the seasonality of temperature and precipitation for Canada and the continental United States.
Figure 9. Seasonality of temperature and precipitation for Canada and the continental United States mapped as four panels with maps of the quartiles of temperature and precipitation seasonality mapped within each panel.
Figure 10. Species richness for the taxa included in this volume for all taxa, conifers, and nonconifers.
Figure 11. Species richness for the taxa included in this volume for taxa whose distributions are unchanged from previous volumes, taxa with revised distributions, and new taxa.
Figure 12. Example graphical display (Atlas Page) for Pinus edulis.
Figure 13. Comparison of information on taxonomy and data sources for four species of Pinus.
Figure 14. Comparison of the gridded distributions of four selected species of Pinus that live under divergent climatic conditions in CANUSA.
Figure 15. Comparison of the presence or absence of four species of Pinus relative to individual climatic variables.
Figure 16. Comparison of histograms for the percentages of the total number of grid points where the taxon occurs relative to annual and bioclimatic variables for four species of Pinus.
Figure 17. Comparison of plots of the presence or absence for the taxon relative to bivariate plots of July Temperature versus log Annual Precipitation, July Temperature versus January Temperature, and log July Precipitation versus log January Precipitation for four species of Pinus.
Figure 18. Comparison of plots of the presence or absence for the taxon relative to four quartiles of AE/PE and within each quartile by MTCO versus GDD5 for four species of Pinus.
Figure 19. Comparison of the presence or absence of four species of Pinus on scatterplots of log of precipitation versus temperature for each month.
Figure 20. Comparison of box-and-whisker plots of monthly temperature and precipitation for the grid points where four species of Pinus occur.
Figure 21. Comparison of the median monthly values of temperature and precipitation for nine selected species of Pinus from CANUSA.
Figure 22. Maps of three species from the arid and semiarid part of western CANUSA, with box-and-whisker plots comparing the monthly temperature and precipitation.

Tables Accompanying Text

Tables 1 and 2 include links to the atlas pages for individual taxa and groups, and can be opened in a web browser by clicking the links below. These and the other tables included in this volume are in Microsoft Excel format and are designed to be opened independently, instead of viewed in a web browser. Free Excel file viewers are available from various sources, including Microsoft and the OpenOffice project. Excel files for these tables are located in the "main_tables" directory of this volume, or tables 3 through 8 can be downloaded individually by clicking the links below.

Table 1. Species included in this volume (includes links to atlas pages for individual taxa).
Table 2. Species composing groups (includes links to atlas pages for groups of taxa).
Table 3. Online resources consulted in the construction of gridded distributions of new taxa for this volume, accessed from 2011–2013.
Table 4. Printed resources consulted in the construction of gridded distributions of new taxa for this volume.
Table 5. Effects of changes in distributions of species and climatology on the estimated relations between distributions and climatic variables.
Table 6. Occurrences of species within World Wildlife Fund ecoregions and major habitat types (MHTs).
Table 7. Climatic data associated with Pinus edulis.
Table 8. Comparison of the median climatic values associated with nine species of Pinus.

Data Tables Containing Relations of Plant Distributions to Single Climatic Variables

These tables are in Microsoft Excel format and are designed to be opened independently, instead of viewed in a web browser. Free Excel file viewers are available from various sources, including Microsoft and the OpenOffice project. Excel files for these tables are located in the "tables" subdirectory of the "individual_taxa" and "groups" directories.

Monthly Individual Taxa Temperature Tables
Monthly Individual Taxa Precipitation Tables
Nonmonthly Individual Taxa Tables

Monthly Group Temperature Tables
Monthly Group Precipitation Tables
Nonmonthly Group Tables

First posted February 25, 2015