Sunday, December 11, 2011

A New Bush Viper & The Strategy to Save it from Extinction

Atheris ceratophora, a species related to
A. matildae. Photo Credit Al Cortex.

Fourteen species of the arboreal viper genus Atheris (subfamily Viperinae), sometimes called bush vipers, are distributed over much of central Africa but seem to reach their greatest diversity in east Africa's sky island complex. The Atheris ancestor originated in Africa's Oligocene and they all use an ambush foraging strategey to capture food. Bush viper have frequently evolved in patches of forest on a mountain top and have stayed put, so most recognized species have limited distributions. Because they depend on forests, many of these snakes are threatened by habitat destruction, but they are also threatened by collectors who feed the wildlife market of developed countries.

This week the journal Zootaxa published the description of a spectacular new species of Atheris, Matilda’s Horned Viper, Atheris matildae which was discovered during a biological survey in southern Tanzania. Superficially It resembles the Usambara bush viper, Atheris ceratophora, but it is larger, has distinct scalation and a genetic divergence of 3.18% in one mitochondrial gene, suggesting the two species separated about 2.2 million years. 

Atheris matildae was discovered in a remote montane forest fragment in southwest Tanzania, a remnant of a more widespread forested landscape that was interspersed with plateau grasslands and other naturally isolated forest islands. The Menegon et al. (2011) suggest that A. matildae is a range-restricted forest species, limited to an area smaller than 100 km2 in an area of declining habitat quailty. 

Wildlife trade is estimated to be US$159 billion a year business and  reptiles play a large part in the exotic wildlife trade that is having a devastating effect on wild populations. So much so, that in many parts of Africa it is the single biggest threat to the existence of many wild species. The colourful, Atheris are popular pet snakes in many countries, however, their natural habitat is seriously threatened and the numbers of wild caught animals destined for the pet trade continues to be unsustainable.

Newly discovered bush viper species can bring a high price and this can have a very damaging impact on the population. In the case of Matilda’s Horned Viper, a sudden rush to collect as many specimens as possible could actually extirpate the species in the wild. To avoid the unsustainable collection of such a rare snake, the authors of the species have agreed with the editor of Zootaxa – where the species description is published – to keep the locality as vague as possible, with the possibility of more specific information provided by the authors on request, scientific purposes only. The authors suggest this practice should be taken into consideration by taxonomists every time a new, rare species of potential commercial interest is described.

While collection from the wild is mostly unsustainable and has reached a level whereby it represents perhaps the biggest threat to Tanzania’s amphibians and reptiles, the authors have propsed a conservation strategy to save the new snake and provide a new conservation opportunity. The authors have initiated a breeding program for the new viper in Tanzania. This will act as an ‘insurance population’ to protect the new species from overexploitation, and begin the conservation of its threatened habitat so that this unique animal can persist in the wild. The first few dozens of babies will n\be placed into the market to produce a commercial population that won't depend upon the wild population. This is an attempt to flood the market with specimens of the new species in order to lower the price and to encourage the captive breeding in the most highly demanding countries, and raise funds to establish an in situ community based forest conservation, programme, including environmental education and wildlife management. The authors will also ask CITES to list the wild population of the species in the Appendix 1 and the captive population in the Appendix 2. Find out more about this strategy at: http://www.atherismatildae.org/

Citation
Menegon, M. T. R.B. Davenport and K M. Howell. 2011. Description of a new and critically endangered species of Atheris (Serpentes: Viperidae) from the Southern Highlands of Tanzania, with an overview of the country’s tree viper fauna. Zootaxa 3120: 43–54.

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