Fig. 4From: What is a tree in the Mediterranean Basin hotspot? A critical analysisLinear regression between the total native tree richness and the surface of each of the 13 biogeographic provinces sensu Rivas-Martínez et al. (2004). Abscissa and ordinate axes have a logarithmic scale. Shade area represents the 95% confidence interval around the predictions. Dots above the line indicate higher richness than predicted by the species-area relationship, and dots below the line indicate lower richness than expectedBack to article page