Bryan Maritz

Conservation of the Threatened Namaqua Dwarf Adder

Bryan Maritz with an adult Namaqua Dwarf Adder.

The Namaqua Dwarf Adder is listed as Vulnerable by the IUCN. Little is known of its biology.

Namaqua Dwarf Adder fitted with radio transmitter.

Regurgutated prey item from juvenile Namaqua Dwarf Adder.

Town/RegionCountryCategoriesDate
Namaqualand CoastSouth AfricaAfrica, Habitat, Pet trade, Reptiles22 Jan 2009

The Namaqua Dwarf Adder (Bitis schneideri) is the world's smallest adder, and is endemic to southern Africa. The species is listed as Vulnerable by the IUCN, but could equally be listed as Data Deficient given the paucity of information on its ecology and conservation biology. This paucity of information demands attention if the species is to be adequately managed within its transforming habitat. The Namaqua Dwarf Adder faces several threats. Most prominent among these is habitat loss resulting from diamond mining activities that are widespread within the species' limited geographic range. Additionally, the Namaqua Dwarf Adder is threatened by illegal collection for the pet trade. Finally, global climate change presents unknown but potentially significant threat to the species, particularly given its location within the Succulent-Karoo Biome. This project arose in recognition of the threats facing this species and others within the region. It is hoped that information gathered during the course of this project will help to identify suitable habitat for the species and motivate for the protection of such habitats.

Primarily, this project hopes to identify the habitat and ecological requirements of the species. Without this information, any efforts to save the species from extinction are prone to being misguided and could potentially fail. Secondly, conservation of Namaqua Dwarf Adder habitat, resulting from the efforts of this project, would result in the preservation of habitats important to other threatened species in the area (of which there are numerous plant and animal species).

As part of the project, an intensive mark-recapture study has been initiated. This component aims to estimate population size, growth and age structure of the population being studied. It involves actively searching for specimens, then marking them, collecting an array of biometric measurements, recording habitat traits, and releasing the specimen. These data are essential as they will inform us as to population size, age structure, and potential fluctuations in Namaqua Dwarf Adder population numbers.

A radio-telemetry study is also being planned as a critical component of this project. This component will allow us to estimate home-range size and other movement parameters, quantify microhabitat utilisation, and collect valuable natural history observations. The radio-telemetry study will involve gluing tiny (<0.8g) radio transmitters to the body of study animals. These transmitters will emit a signal that will allow for the daily location of these cryptic animals.

For more information contact maritz@gecko.wits.ac.za

Project Update: February 2010

Since receiving funding from RSG this project has moved from strength to strength, and we have achieved several of our objectives. Some of the research highlights are described below.

The mark–recapture project that we have been conducting has provided some striking results. Initial results indicate that in suitable habitat, Namaqua dwarf adders occur at high population densities. Such areas may host up to 18 adults per ha, making our study population one of the densest populations of snakes recorded in Africa. This finding has important implications for conservation as previous conservation assessments may have underestimated the size of the global population.

Data from radio tagged snakes have also provided valuable insights into habitat use and behaviour of Namaqua dwarf adders. We have demonstrated that individuals generally exhibit strong site fidelity, with most male and female snakes utilizing small home ranges. Such findings have important implications for gene flow among populations of this threatened species. One possible implication of the sedentary nature of these animals is that populations separated by large areas of unsuitable habitat may show significant genetic divergence. This idea would need to be empirically tested in the future, and would have important conservation implications for the species.

Final Report

Read about the activities undertaken and findings of this project in the final report below.

File DownloadSize
Final Report696.5 KB

Other Projects in: