VILLANOVA, Pa. – Villanova University Professor of Biology Aaron Bauer, PhD, was part of an international team of scientists that completed the ‘atlas of life’—the first global review and map of every vertebrate on Earth. Led by researchers at the University of Oxford and Tel Aviv University, the 39 scientists produced a catalogue and atlas of the world’s reptiles. By linking this atlas with existing maps for birds, mammals and amphibians, the team have found many new areas where conservation action is vital.
In order to best protect wildlife, it’s important to know where species live, so the right action can be taken and scarce funding allocated in the right places. With this in mind, the researchers produced detailed maps highlighting the whereabouts of all known land-living species of vertebrate on Earth. Maps showing the habitats of almost all birds, mammals and amphibians have been completed since 2006, but it was widely thought that many reptile species were too poorly known to be mapped.
In research featured in Nature Ecology & Evolution, scientists from more than 30 institutions worked in close collaboration to produce the new reptile atlas, which covers more than 10,000 species of snakes, lizards and turtles/tortoises. The data completes the world map of 31,000 species of humanity’s closest relatives, including around 5,000 mammals, 10,000 birds and 6,000 frogs and salamanders.
Dr. Bauer, who serves as the Gerald M. Lemole Endowed Chair in Integrative Biology at Villanova, was one of several American contributors to the paper. His study of organisms, geckos, skinks and other lizards include many of those reptiles that add to the desert richness. Dr. Bauer’s decades of field work in the deserts of southern Africa, Asia and Australia have helped to reveal not only patterns of distribution, but to document the diversity of reptile species. Bauer has described more new species of reptile than any other living scientist, including more than seven percent of the more than 1,600 living geckos.
“This research takes a global approach to understand the factors associated with the distribution of reptiles,” said Dr. Bauer, who also serves as the Gerald M. Lemole Endowed Chair in Integrative Biology at Villanova University. “Unlike other tetrapod vertebrates (mammals, birds and amphibians), for which distributions have been known for some time, reptiles have until now been left out of the picture of vertebrate spatial diversity.”
Data for the other groups has been compiled, largely through the auspices of the International Union for the Conservation of Nature (IUCN), which draws up the red lists of threatened and endangered species. With no concentrated effort from the IUCN for a comparable project on reptiles, the authors of this paper, representing experts on reptile faunas from around the world, took it upon themselves to develop distribution maps for the more than 10,000 living reptile species based on museum specimens, literature records and their own field experience.
The combined maps allowed the team to examine the broad patterns of reptile diversity across the earth. While other vertebrates mostly show their maximum diversity in the wet tropics, such as Amazonia and Southeast Asia, reptiles reveal a somewhat different pattern, with high diversity in deserts as well as in tropical forests.
“This difference is driven by lizards, the most diverse group of reptiles, which have been especially evolutionarily successful in arid parts of the world,” added Bauer. “Thus, places like Australia, southern Africa, and parts of the Middle East show up as hotspots for these animals. This difference in diversity distribution has implications for conservation as it means that national parks and other protected areas selected to protect, for example, birds, may not be well-placed to conserve the diversity of reptiles.”
The map revealed unexpected trends and regions of biodiversity fragility. They include the Arabian Peninsula and the Levant, inland arid southern Africa, the Asian steppes, the central Australian deserts; the Brazilian caatinga scrubland, and the high southern Andes. The maps have also allowed conservationists to ask whether environmental efforts to date have been invested in the right way, and how they could be used most effectively.
The data collected by the group will also allow researchers to ask many other macroecological questions, such as “Are there differences in the spatial distribution of live-bearing versus egg laying reptiles?”; “Do larger species have larger distributional ranges than smaller ones?”; or, “How have rates of evolutionary differentiation varied across the globe?” Although reptiles are mostly inconspicuous in temperate areas, like Pennsylvania, their diversity and biomass is surprisingly high and they play important roles in maintaining terrestrial and freshwater ecosystems.
The International Union for the Conservation of Nature (IUCN) are currently classifying the species featured in the map with a rating, from “critically endangered” to “least concern.” Once this work is complete, the interactive resource will be freely available for public access and use. Moving forward, its creation will allow a range of stakeholders, from countries, to conservation organizations, businesses and individuals, to understand the biodiversity in their surrounding environment, its importance and, crucially, what they can do to better protect it.
The paper is available at Nature Ecology & Evolution.