Climatic Controls of Eastern North American Coastal Tree and Shrub Distributions

Abstract

The geographic ranges of six coastal tree and shrub species were assessed against paired combinations of climate variables in order to define the most precise climatic envelope for each species. Four different methods were used to define the statistical distribution of climate variables for species range prediction. The current species range maps were then compared to predicted range maps as a test of all combinations of climate variables and statistical methods. For the species tested, actual evapotranspiration and growing degree day indi- ces, processed with an elliptical distribution model and data exclusion techniques, proved to be the most accurate climatic predictor of species ranges. This assessment demonstrates that identification of the statistical central tendency of the climatic distribution of a species allows for the definition of a core range of climatic features and significantly increased predic- tive ability.