Magnitude of (a) biotic and (b) climatic velocity for Western Hemisphere ecoregions.

<p>Results are shown for the period 1961–2100 under the SRES A2 scenario. The bivariate chloropleth plot jointly represents both forward and backward velocity, allowing categorization of ecoregions into the 4 threat quadrants shown in the inset (d). To create the 9 categories shown in (c), log-transformed velocity values (km/year) were grouped into three equal area quantiles along each axis.