Conservation managers at a reserve in Dubai are hoping to set up an exchange with an overseas zoo to introduce new genes into their small population of a rare species of oryx. Birth rates in the tiny group of scimitar-horned oryx at Dubai Desert Conservation Reserve have declined in recent years, leading to concerns of inbreeding.
About 10 calves have been born since 2001, when the animals were introduced to the park, a 225-square-kilometre area on the road between Dubai and Al Ain, from the private collection of Sheikh Mohammed bin Rashid, Vice President of the UAE and Ruler of Dubai. However, the last new arrival was a year ago and Greg Simkins, the conservation manager at the reserve and Al Maha Desert Resort and Spa that lies within it, said greater genetic diversity was needed.
"We've had the scimitar-horned oryx for quite a while," he said of the 14-strong herd. "We've got through a successful period, but there's a general slowing down in the number of animals being born. We need to get new genes into our herd for it to be more successful." The herd appears to be suffering from inbreeding depression, a reduction in fitness and fertility that results when closely related animals breed.
When distantly related animals mate, the young are more likely to be healthy because, for any one gene, the chances are low they will inherit harmful forms from both parents. A damaging form of a gene from one parent will probably be masked by a normal version from the other. Closely related parents are similar genetically, so their offspring will inherit the same types of genes from both parents. Among the identical pairs of genes the young will carry could be harmful forms.
This appears to be happening in the reserve's population of the scimitar-horned oryx. It means the females are less likely to conceive and are at greater risk of miscarriages. Breeding programmes for the oryx are important as the creatures survive only in zoos and conservation parks, although the species was once common in North Africa, ranging widely across the Sahara desert. The white and brown creatures, which eat grass, roots and buds and weigh up to about 210kg, gathered in their thousands for epic migrations.
A combination of hunting, desertification and human encroachment on habitats drove the animals to extinction in the wild. While there are several private collections in the UAE, as well as one at Al Ain Zoo, Mr Simkins, a South African who has worked at Al Maha Desert Resort since it opened in 1999, is looking further afield for the exchange. He is hoping to set up a swap with a herd of scimitar-horned oryx in North America or Europe. The benefits, he said, would be two-way.
"We could get animals from another collection within the UAE, but they are from the same founding animals and from the same place, so an exchange programme within the UAE is pointless," he said. "Our animals originated from a different source to the animals in European or North American zoos, so they would be very valuable [for exchange]." The reserve's animals are being DNA tested and the results will be made available to international conservation authorities, which will recommend herds the reserve could exchange with.
"It has been a lengthy programme over the past two years and hopefully this winter we'll be able to do something," Mr Simkins said. The scimitar-horned oryx is not the only large mammal the reserve is trying to conserve. As well as 74 bird species and 24 types of reptile, there are also Arabian gazelle, sand gazelle, Arabian oryx and nine other mammal species. With the Arabian oryx, the concern is not that there are too few animals, but that there could be too many, he said.
"There are six herds of about 20 to 30 animals, and a total of approximately 270 individuals. "In the UAE, there are an estimated 4,000 Arabian oryx, with the Environment Agency Abu Dhabi among the organisations involved in breeding them. "If you go back 100 years, [in the wild] oryx numbers would probably climb and [the herd would] utilise an area and then move on. "They would be able to migrate to areas with fresh growth and give an area that had been over-utilised an opportunity to recover."
Now, the animals cannot migrate to another area and so rather than let their population grow to an unsustainable level and let the reserve became overgrazed, Mr Simkins is considering controlling numbers. "When you have a herd of high numbers, it could have a negative effect on the environment, then you would have die-outs," he said. "You could go through this cycle a number of times, so in smaller reserves you need to manage the process."
To find out how many Arabian oryx and other species the reserve can maintain, a vegetation survey is being carried out. The one-year project, which is halfway through being completed, is surveying the abundant of plant species across the reserve. By taking into account how much vegetation the animals typically consume, the ideal population size can be calculated. If the numbers of individuals exceed this number, action will be taken, but Mr Simkins said culling was "the last option".
Up to now, the Arabian oryx at the reserve have enjoyed a slightly spoiled lifestyle, with feeding stations with hay, alfalfa pellets and mineral licks set up to encourage population growth. Four-fifths of the reserve's oryx population depend on these stations. With numbers potentially getting too high, the pampered lifestyle may become a thing of the past. "We're looking at reducing their supplementary food," Mr Simkins said.
"That would reduce the number of calves. It would be a subtle influence on the population." Another option would be to send animals to other reserves, either in the UAE or other parts of Arabia. "The first step is to establish what numbers you can have, and take it from there," he added. Arne Silvis, the general manager at Al Maha, said the breeding programme was part of the resort's philosophy.
"Of course we are a business, but the people here genuinely care about what they are doing," he said. "We are trying to use less and less water and electricity. It is a five-star resort, so those levels are not very low, but they are significantly lower than other hotels. "And despite the success we have had, there is no pressure to increase the amount of suites from the 49 we have now. "It is important we have conservation as our priority."