1 Tahrcountry Musings: Re-introductions and the Use of simulation program VORTEX

Monday, February 21, 2011

Re-introductions and the Use of simulation program VORTEX

Assessing re-introductions of the African Wild dog (Lycaon pictus) in the Limpopo Valley Conservancy, South Africa, using the stochastic simulation program VORTEX

Lars A. Bach, Rikke B.F. Pedersen, Matt Hayward, Jesper Stagegaard Volker Loeschcke and Cino Pertoldi

Here is a good paper on reintroduction and use of simulation programme VORTEX. The work was done on African wild dog (Lycaon pictus), in the Limpopo Valley Conservancy, South Africa.

Even though it once ranged throughout Africa, currently the African wild dog only has populations larger than 300 individuals only in three countries (Botswana, Tanzania and South Africa).

In 1998, a plan was launched in South Africa for reintroduction of wild dogs into suitable conservation areas and periodic translocations among them.

The researchers used the stochastic population simulation model VORTEX to evaluate the Limpopo Valley Conservancy in the north of South Africa, as a possible reintroduction site for African wild dogs.
The simulations by the researchers showed that the size of the initial population released only had a small effect on the population dynamics. However, when individuals were supplemented and harvested over a longer period the probability of persistence increased.

Number of females breeding, male mortality, and carrying capacity were key factors in the population dynamics, but simulations by the  VORTEX showed that the severity of natural catastrophes had the greatest influence on the extinction risk and inbreeding.

The researchers suggest that the reintroduction program may be successful, if areas are properly secured, the dogs are held in a boma before release, wild animals or at least a mix of wild and captive animals are used for the release and the animals are vaccinated against rabies.  They reiterate that it is essential to continue monitoring followed by modelling efforts to re-evaluate the success of the reintroduction program.

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