Electronic Supplementary Material
Table 1 PD losses if species in currently recognized threatened categories are extinct. IUCN categories: VU – Vulnerable;
EN – Endangered; and CR – Critically Endangered.
IUCN Threat status
VU + EN + CR
EN + CR
CR
Number of species
1004 (21%)
552 (12%)
151 (3%)
PD loss if the species are
extinct (million year)
8470 (14%)
4312 (7%)
1106 (2%)
[8044, 8803]
[4249, 4839]
[1066, 1380]
Terminal branch length loss
if the species are extinct
(million year)
5700
2783*
740
Two-tailed 90% quantile of
terminal branch loss from
random extinction
simulation (million year)
[5458, 6387]
[2847, 3567]
[661, 1068]
Internal branch length loss if
the species are extinct
(million year)
2771
1529
365
[2232, 2760]
[1136, 1544]
[253, 480]
Two-tailed 90% quantile of
PD loss from random
extinction simulation
(million year)
Two-tailed 90% quantile of
internal branch loss from
random extinction
simulation (million year)
*At the global scale, endangered species tend to be on shorter terminal branches, resulting in underestimates of the impact of
global extinction on regional communities and ecosystems.
Fig. S1. Hypothetical phylogeny (branch lengths indicated as the numbers above the branches) of species assemblages in
two different areas illustrating how losing the same number of species can lead to low (A) or high (B) loss of local
phylogenetic diversity. The PD of the original species assemblages in both area A and B are the same: PD originalA =
PDoriginalB = 17.5 myr. If threatened species (in red) become extinct, the remaining species would only have PD remainingA =
11 myr in (A) and PDremainingB = 9 myr in (B). By our definition, these two assemblages (areas) would have lost different
amounts of PD due to loss of the same total numbers of species: PDlostA = 6.5 myr but PDlostB = 8.5 myr.
Fig. S2. The relationship between percent loss in phylogenetic diversity (PD) and species richness (SR) through random
extinction (terrestrial mammals, n = 4796). For each level of SR loss, random extinction was simulated for 1000 times.
Fig. S3. Results of the comparison between estimated and simulated PD loss in 1000 simulations for each 10,000 km 2 grid
cell. Areas shown in red will lose greater PD following the loss of currently threatened species than at least 95% of all
random extinction events (assuming the loss of the same number of randomly chosen species). Phylogenetic trees of
species in two example grid cells (green cells, indicated by arrows), one in the Amazon and the other in South Asia, are
illustrated in Fig. S2-3.
Figure S4. The phylogeny of species in a grid cell in the Amazon, as indicated on figure S1. Branches to be lost are colored
in red. Only threatened tips (species) are visibly labeled with species Latin binomials.
Figure S5. The phylogeny of species in a grid cell in the South Asian biodiversity hotspot, as indicated on figure S1.
Threatened species are labeled in bold and branches to be lost are colored in red. Note that 6 out of 7 species of primates
(labeled) from this location are threatened with extinction.