Reptiles under threat

South Africa and its neighbours Lesotho and Swaziland have the world's third most diverse reptile fauna – a population documented in the Animal Demography Unit's most recent atlas. But the conservation of almost one-fifth of these species and sub-species is of extinction concern, because of habitat destruction and alteration.

UCT's Animal Demography Unit (ADU) has co-ordinated and recently launched their fourth atlas, Atlas and Red List of the Reptiles of South Africa, Swaziland and Lesotho, published as the first monograph of the new South African National Biodiversity Institute (SANBI) Suricata series on various South African animals.

The atlas lists the conservation status of the Southern African region's 422 species and sub-species of snakes, lizards, tortoises and turtles, some 45% of which are endemic to this area.

Data-rich, it includes information on the distribution and habitat of each species, as well as the threats to its survival, and the conservation measures needed to ensure it stays off the endangered species list.

Words and pictures

Featuring distribution maps for, and photographs of, each reptile (a first), the publication is the product of 135 512 records, gathered by leading reptile scientists and citizen scientists, under the auspices of the South African Reptile Conservation Assessment (SARCA).

As such, it's the most thorough assessment of reptile conservation ever completed in Africa, says ADU director Emeritus Professor Les Underhill.

And long overdue – the last Red Data Book was compiled by Bill Branch and published in 1988. Since then, 200 additional species have been recognised – an increase of 50% on previously recognised diversity.

"Many taxa were previously considered sub-species, but have been elevated to full species," says Underhill.

Some 405 taxa were assessed, 90% of which had never been assessed before, according to the International Union for the Conservation of Nature's (ICUN) Red List system, an internationally endorsed scientific approach to assessing species' extinction risks.

Until now, many maps for reptiles had been based partly on data, but largely on guesswork. For the first time, maps are available for each species showing only the places where it has actually been found. Such pin-point species information provides the foundation for conservation plans.

The conservation message is paramount, Underhill emphasises.

Conservation crucial

Because most reptiles are predators and help control populations of pest species such as rats, mice, mosquitoes, flies and termites, they have a large impact on ecosystems.

"SARCA sprang from the realisation that reptiles as a group have largely been ignored in conservation planning – not only in South Africa, but globally," says Dr Marienne de Villiers, SARCA project manager and one of the atlas's seven editors.

"This is largely due to a lack of information. To conserve something you need to know what you have, where it occurs, and how well or poorly it's doing, and what is threatening it.

"In 2003, when Professor Graham Alexander of Wits and ADU's James Harrison incubated an innovative plan to address these issues, it was evident that much of this information was missing for the reptiles of the region. There was information on the distribution of species, but it was scattered, and not easily accessible."

The atlas gives a much clearer picture: that one in every five of the region's species is of conservation concern; two are extinct and 36 are threatened with extinction. The loss of the two extinct species, both lizards, can be attributed to afforestation in one case and urban development in the other. Both originally had restricted distributions.

In common with the findings for many other groups of species, the main threats to reptiles are habitat degradation and loss through agriculture, afforestation, alien invasive vegetation and urbanisation.

But the publication is not a field guide, says Underhill. It's intended for conservation planners and managers, researchers, legislators and environmental consultants; as well as professional and amateur herpetologists.

UCT's Animal Demography Unit co-ordinated the recently launched the Atlas and Red List of the Reptiles of South Africa, Lesotho and Swaziland. It joins works on birds, butterflies, insects, and frogs.

Story by Helen Swingler.