Equilibrium of species’ distributions with climate

The degree to which species’ distributions are at equilibrium with current climate is an important issue in the ecological literature (Davis 1986, Gaston 2003). Distinguishing the relative roles of present and past climates in determining species’ distributions is not only of theoretical interest, but is key to understanding responses of species to climate change. Recent work has demonstrated significant departures from equilibrium with current climate for tree distributions in Europe (Svenning and Skov 2004), yet differences in the degree of equilibrium can be expected across organisms whose dispersal abilities (and hence ability to track changing climate conditions) vary greatly. Here we assess differences…