1. Most species derive at least two-thirds of their Evolutionary Distinctiveness (ED) from the terminal branch, but the branch length is a poor predictor of total ED.
2. ED scores in primates are tightly correlated under different species concepts, but species that have been split into multiple species lose a large portion of their ED.
3. Mammal ED scores range from 0.0582 MY to 97.6 MY, with a median of 7.86 MY.
4. Least Concern species have significantly lower ED than other Red List categories, suggesting low extinction risk.
5. EDGE scores range from 0.0565 to 6.48, with a mean of 2.63. The top 100 priority species include large-bodied mammals and smaller, lesser-known species.
6. Threat status alone does not guarantee a high priority on the EDGE list.
Although most species (90% in figure 2) derive at least two-thirds of their total ED from the terminal branch (which is not shared with others), this branch length is a poor predictor of total ED (r2 = 0.03 on a log-log scale). For species on short branches, there is an order of magnitude difference between the length of the terminal branch and ED. For example, the pale-throated and brown-throated three-toed sloths (Bradypus tridactylus and B. variegatus) share a common ancestor thought to be just over a million years old, but the total ED of both species is 20.4 MY (Table S1) since they have few close living relatives.
ED scores are also robust to taxonomic changes. For example, ED scores in primates under the biological species concept [35] are tightly correlated with ED scores under the phylogenetic species concept [36] (r2 = 0.65 on a log-log scale), in spite of the fact that there are substantial differences between the two: the number of primate species differs by 50%. Furthermore, the highest-ranking species do not change their identity: 45 of 58 biological species in the upper quartile of ED scores are also in the upper quartile as phylogenetic species. However, species that have been split into three or more species do tend to lose a large portion of their ED. For example, the fork-marked lemur (Phaner furcifer) is the second most distinct biological species of primate, with an ED score of 38.33. It was split into four phylogenetic species [36] with an ED score of 10.45 (Table S2), which is just inside the upper quartile.
ED and EDGE scores in mammals
Mammal ED scores range from 0.0582 MY (19 murid rodents) to 97.6 MY (duck-billed platypus, Ornithorhynchus anatinus). Scores are approximately log-normally distributed, with a median of 7.86 MY and geometric mean of 6.28 MY.
Evolutionary Distinctiveness is not evenly distributed among the Red List categories. Least Concern species have significantly lower ED than the other categories (F1,4180 = 26.3, p<0.0001, using loge transformed scores); there are no significant differences among the remaining categories. This suggests that species with low ED scores tend to suffer from low levels of extinction risk, although the explanatory power of this model is extremely low (r2 = 0.006).
EDGE scores range from 0.0565 (10 murid rodents) to 6.48 (Yangtze River dolphin or baiji, Lipotes vexillifer) and are approximately normally distributed around a mean of 2.63 (±0.017; figure 3). The 100 highest priority (EDGE) species includes several large-bodied and charismatic mammals, including the giant and lesser pandas, the orang-utan, African and Asian elephants, four rhinoceroses, two tapirs, two baleen whales, a dugong and a manatee. However, many smaller and less appreciated species also receive high priority, including sixteen rodents, thirteen eulipotyphlans, twelve bats, four lagomorphs and an elephant shrew (Table S1). The top 100 also includes at least 37 species that would not qualify for most area-based definitions of endemism, since they are listed as threatened under Red List criterion A (reduction in population size) without qualifying for criteria B–D, which are based on population size or geographical range. Whilst the highest-ranked species, by definition, are all highly threatened (44 of the top 100 species are Critically Endangered, a further 47 are Endangered), threat status alone does not guarantee a high priority. For example, 10 Critically Endangered species (in the genera Gerbillus, Peromyscus and Crocidura), as well as 32 Endangered species, fail to make the top 1000, whilst 130 Near Threatened species do.
Extract only the main points for the information given above mentioned information
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