In this post for Endangered Species Day Jared Stabach, a research ecologist at the Smithsonian Conservation Biology Institute highlights the sharp decline in large mammal species across the Sahara and focuses on species that individuals and organizations are working to reintroduce.
Deserts cover approximately 17% of the world’s land mass. While understudied and underappreciated, these systems support a unique and charismatic flora and fauna, with species that have evolved remarkable adaptions for survival. The Sahelo-Saharan region, for example, is most impressive, supporting a diverse ungulate assemblage that include addax, dama gazelle, dorcas gazelle, and scimitar-horned oryx. Sadly, many of these species persist across a small fraction of their former range, a result of range restriction, habitat degradation, increased competition with livestock, and overhunting. Others, such as the scimitar-horned oryx, valued for the meat and quality of their pelt, are now extinct in the wild altogether.
Hope, however, does exist thanks to dedicated individuals and organizations globally. The captive population of scimitar-horned oryx, for example, now number in the thousands (est. 5,000 – 10,000 individuals), highlighting the strength of the zoo and captive breeding community and providing an opportunity for conservation intervention. In 2016, after years of planning, and thanks largely to the Environment Agency – Abu Dhabi, the Sahara Conservation Fund, and the government of Chad, the first 23 of potentially 300-500 scimitar-horned oryx were reintroduced to the Ouadi Rimé-Ouadi Achim Game Reserve, a large fenceless reserve in central Chad where the ancestors of these individuals were “taken” many decades ago. John Newby, Director of the Sahara Conservation Fund, said it best, “the long lost daughters and sons of Chad have returned.”
A population of 113 free-ranging scimitar-horned oryx animals now persevere across this harsh landscape, comprised of 69 adults reintroduced in two separate waves and a boom in calves (44) over the past year, many of which were conceived in the wild. A third wave of animals will be reintroduced later this year when vegetative conditions improve, increasing the population in the reserve to nearly 200 individuals. While it is too early to label the reintroduction effort a success, early progress is encouraging.
The species, which derives its name from its long curved horns, has evolved many adaptations for survival. Their white coat helps reflect the sun’s powerful rays and their black skin protects them from sunburn. Enlarged hooves enable the species to walk easily on sand and their long legs enable animals to traverse long distances while keeping their core as far away from the hot desert surface as possible. Importantly, the species has highly evolved kidneys, which allow them to survive without drinking surface water for months at a time, extremely important in an environment that has a single wet season annually. In addition and importantly, scimitar-horned oryx sweat very little to more efficiently conserve water by allowing their internal body temperature to fluctuate (potentially as high as 116°F [46.6°C]), a response exhibited by many dryland-adapted ungulates.