Abstract

Climate is the primary factor controlling the continental-scale distribution of plant species, although the relations between climatic parameters and species' ranges are only now beginning to be quantified. This volume examines the relations between climate and the distributions of (1) Küchler's "potential natural vegetation" categories for the 48 contiguous States of the United States of America, (2) Bailey's ecoregions of North America, and (3) World Wildlife Fund's ecoregions of North America. For these analyses, we employed a 25-kilometer equal-area grid of modern climatic and bioclimatic parameters for North America, coupled with presence-absence data for the occurrence of each ecoregion under the three classification systems under consideration. The resulting relations between climate and ecoregion distributions are presented in graphical and tabular form. Presentation of ecoregion-climate relations here is intended to be useful for a greater understanding of ecosystem evolution, ecosystem dynamics, and potential effects of future climate change on ecoregions.

¹ Earth Surface Processes Team, U.S. Geological Survey, Denver, Colo.
² Institute for Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, Colo.
³ Earth Surface Processes Team, U.S. Geological Survey, Corvallis, Oreg.
⁴ Department of Geography, University of Oregon, Eugene, Oreg.

First posted September 8, 2009