Since joining the RZSS WildGenes team in October last year, I’ve been working on some of our antelope projects. The team have a lot of experience in using genetics as a tool to help in the conservation efforts of arid-land species. One such species is the addax (Addax nasomaculatus), which is native to the Sahara and Sahel regions of Africa. The addax is a large antelope with enormous spiralling horns, a desert specialist and well adapted to the hot, sandy environment.
(PICTURE: Addax roam great distances to find food, often overnight to avoid the heat of the day, and rarely need to drink water, gaining most of what they need from the plants they eat and the morning dew. Their broad, flat hooves help to prevent them from sinking into the sand (photo by Thomas Rabeil, Sahara Conservation Fund).
Sadly, like many of the species we study here at WildGenes, the addax is critically endangered. These large animals were once relatively easy to spot resting or trekking across the wide-open desert. However, recent surveys by the Sahara Conservation Fund (www.saharaconservation.org) have struggled to find more than a handful of individuals in their last remaining strongholds in Niger’s Termit & Tin Toumma Reserve or in Western Chad. Like the Nubian Ibex featured in December’s blog, motor vehicles and modern weapons have increased levels of hunting, and, along with disturbance from oil exploration and the encroachment of livestock, these threats have pushed the addax to the brink of extinction.
(PICTURE: The last known populations of addax are in Niger and Chad, but they once thrived throughout the Sahara and Sahel regions of northern African. Addax had previously become extinct in Tunisia but were reintroduced in the late 1980s.)
In the late 1980s, 14 addax from US and European zoos were re-introduced into the Bou Hedma National Park in Tunisia. Since then, the population has grown, a further 13 captive addax were released, and they have been translocated across three national parks in Tunisia, forming what is called a metapopulation. These re-introduced addax are living back within their native range, surviving and reproducing within their natural habitat, and form a vital part of the recovery for this species.
So where does our genetics research come in?
Small, isolated populations are at risk of losing genetic diversity and suffering from inbreeding. We know from previous work here within the WildGenes laboratory that wild addax were, once, genetically diverse. What we don’t yet fully understand is how genetically diverse the Tunisian metapopulation is, nor the captive populations in zoos within Europe, the US or Arabia. The WildGenes lab is working with several partner organisations - Marwell Wildlife, Al Ain Zoo in the United Arab Emirates, San Diego Zoo Global in the USA, and the Tunisian Direction Générale des Forêts - to investigate the genetic diversity within these populations. Crucially, this data will help us to develop a global management plan for addax by identifying which animals should be translocated within the Tunisian metapopulation, as well as determining which captive populations could be used to supplement the herds in Tunisia.
(PICTURE: Addax were reintroduced to Tunisia in the late 1980s, photo by Marie Petretto, Marwell Wildlife)
Marwell Wildlife and the Direction Générale des Forêts in Tunisia collected samples from 104 of the 108 known animals in the three national parks – an impressive proportion of the population! Once the samples reached the RZSS WildGenes team here in Edinburgh, we extracted DNA and ran several genetic tests. We are assessing diversity across the whole genome, and much of my time is currently spent analysing the vast amounts of data. It is exciting to know that, in the near future, we’ll be able to provide our partners with the vital genetic information they need to help secure a future for the addax.
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