Figure 2. Global patterns of (a) species richness and (b) Faith’s phylogenetic diversity (PD) for all angiosperms, palms and ferns on islands.
PD was calculated as the sum of all branch lengths representing the species of an island in a clade’s phylogeny18 excluding the root, based on a dated family-level phylogeny for angiosperms and on dated genus-level phylogenies for palms and ferns. PD is shown only for islands with at least two species of the focal group (363 of 375 islands for all angiosperms, 71 of 386 for palms and 234 of 328 for ferns). Species richness is given in numbers of species, PD in billion years. Numbers in legends indicate category borders. Maps were created using the statistical programming language R.