A new map of the global biodiversity of terrestrial vertebrates that is 100 times more detailed than earlier projects is now revealing where conservation efforts for mammals, amphibians, and birds might best be focused, findings detailed this week in the Proceedings of the National Academy of Sciences.
Identifying which areas might be rich in biodiversity is key to directing conservation resources. Conservation scientist Clinton Jenkins at North Carolina State University and his colleagues mapped priority areas for vertebrate diversity using the most recent data on where more than 21,000 species of mammals, amphibians, and birds are clustered. The map has a scale of 10 kilometers by 10 kilometers, 100 times finer than previous efforts, and one comparable to regional decisions on where to set up protected areas. (Reptiles were not included because there is not yet a complete global dataset for them.)
This new map noted which species had small ranges, which are especially vulnerable to extinction, as well as which species are currently threatened according to the International Union for the Conservation of Nature. The researchers also mapped recent species discoveries, which are typically found in largely unexplored regions where as-yet-unknown species might also live.
The greatest numbers of bird and mammal species were found in the moist forests of the Amazon, the Brazilian Atlantic Forest, Congo, the Eastern Arc in Africa, and the Southeast Asian mainland and islands. The pattern for amphibians was similar, but exceptional diversity of them was also seen in the Neotropics — that is, Central and South America.
Small-ranged birds and mammals both have concentrations in the Andes, Madagascar, Southeast Asian islands, and other scattered localities, while so many amphibians have such tiny ranges that relatively few places have large concentrations. Altogether, the centers of diversity for small-ranged vertebrates cover 8.2 percent of the world’s land area but include an extraordinary 93 percent of all vertebrate species.
“That means an exceptionally small amount of the world is extraordinarily important for preventing vertebrate extinctions,” Jenkins says.
Based on the latest data from the World Database on Protected Areas, Jenkins and his colleagues argue the level of protection these priority areas receive is not enough given their importance. Only a third of the centers of diversity for species overall has any protection, and only 11 percent has strict protection. The situation for centers of diversity for small-ranged and threatened species is even greater cause for concern — less than 20 percent of either has protection, and only 10.2 percent of small-ranged species and 7.1 percent of threatened species have strict protection.
“We can prevent most extinctions in the world, but only if we focus conservation efforts on the right places,” Jenkins says.
The scientists found substantial differences between their priority areas for vertebrate diversity and the current leading priority map for global conservation, which is based on plant- and land-based Myers biodiversity hotspots — regions that are rich in endemic plants but have suffered great loss of habitat. The 25 Myers hotspots cover about 12.5 percent of the world’s land area and include about 78 percent of the vertebrate species the investigators considered, significantly larger than priority areas Jenkins and his colleagues identified while including substantially fewer species.
The scientists do note that mammals, amphibians and birds only comprise a tiny fraction of the planet’s total species.
“Unfortunately, we still do not have detailed global datasets for most taxa, such as most invertebrates,” Jenkins said.
Future maps could include reptiles, invertebrates, plants, and fungi, the researchers said.
“I would really like to look at patterns of reptile diversity, because I suspect they will differ substantially from other land vertebrate taxa,” Jenkins says. “Another critical next step is to carefully produce maps of remaining habitat for individual species, ones that rely on solid ecology and not short cuts with exceptionally complex statistical models that most users do not fully understand.”