Across one of Saudi Arabia’s largest protected desert landscapes, a conservation experiment that began in the 1990s is still visible two decades later. A total of 313 captive-bred Arabian and sand gazelles were released into Uruq Bani Ma’arid, where their movements were first followed with radio tracking. When researchers returned in 2015–2016, a large camera-trap survey showed that both species had established populations, although they used different parts of the reserve. Sand gazelles also shifted their range with the seasons, while Arabian gazelles changed their activity as temperatures rose, spending more time active at night and around dawn and dusk.
Saudi Arabia gazelle reintroduction began with 313 captive-bred animals
The gazelles belonged to two species with a long association with the Arabian Peninsula. The Arabian gazelle, Gazella arabica, and Arabian sand gazelle, Gazella marica, are both globally threatened. During the mid-to-late 1990s, groups of captive-bred sand gazelles and Arabian gazelles were released at several locations within Uruq Bani Ma’arid. The approach was spread over multiple sites and carried out over a period of roughly two to three years, rather than relying on a single release point.That detail mattered because the objective was not simply to put animals into the desert. The wider conservation strategy was to establish populations in suitable habitat where the animals could remain protected and reproduce. The early movements of the released gazelles were followed using VHF radio-tracking. It gave researchers a way of seeing where individual animals went after release and how they began occupying the protected area.
Camera traps revealed where the reintroduced gazelles settled 20 years later
According to the study published in Journal of Arid Environments, titled ‘The conservation status of the threatened gazelles of Ar Rub’ al-Khālī, Saudi Arabia‘revealed by 2015 and 2016, about 20 years had passed since the original reintroductions. Conventional wildlife surveys can be difficult across a landscape as large and remote as Uruq Bani Ma’arid, particularly when animals are dispersed across different habitats.This time, a large network of camera traps was used. The cameras provided a much broader picture than following a limited number of radio-collared animals. They could record wildlife across different parts of the protected area and over extended periods, allowing researchers to examine both distribution and relative abundance.What emerged was not a population concentrated around the original release sites. The Arabian gazelles had become established across the western part of Uruq Bani Ma’arid. Sand gazelles occupied a broader central area, with their distribution changing with the seasons.
The reintroduced sand gazelles still followed seasonal habitat patterns
The sand gazelles showed a particularly clear seasonal movement. During the cooler part of the year, they moved further into the interior of the protected area. When temperatures rose, they shifted back towards the western margin. The pattern fits with the animals’ established relationship with their desert habitat. Rather than remaining in one fixed section of the reserve throughout the year, they adjusted their movements as environmental conditions changed.The long-term observations also indicated that the reintroduced animals had retained habitat preferences associated with their species. Captive breeding and subsequent release had not apparently erased those behavioural patterns. For conservation programmes, that provides a useful piece of information. A population does not necessarily need to occupy every part of a protected landscape to be considered established. Its use of the landscape can instead reflect the ecological conditions it has evolved to handle.
Arabian gazelles changed their activity patterns with the desert heat
The gazelles were also responding to the desert in another way: when they were active. During the hot season, Arabian gazelles shifted towards activity during the night and around dawn and dusk. Sand gazelles showed a similar, though less pronounced, seasonal change.In the cooler season, activity was more concentrated during daylight and the periods around sunrise and sunset.That change offers another glimpse into how the animals use an extreme environment. When daytime temperatures become difficult, activity can move towards cooler parts of the 24-hour cycle. Once conditions are moderate, the animals can spend more time active during daylight.
Both gazelle species survived and established populations after 20 years
The significance of the later camera-trap survey was its timescale. Wildlife reintroductions can look promising soon after animals are released, when the focus is often on survival and the first signs of reproduction. A population that remains present decades later provides a different kind of evidence.In Uruq Bani Ma’arid, both reintroduced species had established populations roughly two decades after the original releases. Their distributions were different, but neither had simply disappeared from the protected landscape. The Arabian gazelle had become established mainly in the western portion, while the sand gazelle had spread through much of the central area and shifted its range seasonally.The findings therefore went beyond confirming that released animals had survived. They showed that the two species had continued to use the desert in ways broadly consistent with their known ecological preferences.
A protected landscape made the reintroduction possible
Uruq Bani Ma’arid occupies part of the western Rub’ al-Khali, one of the great desert landscapes of the Arabian Peninsula. Its enormous scale creates conditions very different from those found in a small wildlife enclosure or intensively managed reserve. The 12,684-square-kilometre protected area offered enough space for the animals to spread into different habitats and alter their movements according to the season.That scale also explains why the camera-trap work was useful. Following animals individually across such a large and difficult landscape would have obvious practical limits. A broad array of cameras could instead collect observations from many locations and build up a picture over time.
Reintroduced gazelles retained distinct habitat preferences
Although both species were released as part of the same wider restoration effort, their later distributions were not identical. Arabian gazelles were associated more strongly with the western side of the protected area. Sand gazelles were more widely distributed through the centre, while also making a pronounced seasonal movement towards the interior during cooler conditions and back towards the western edge during hotter periods.Those differences are important because successful restoration does not necessarily mean making two species behave in the same way. Each species brought its own ecological preferences into the restored landscape. The fact that those patterns remained visible years after captive breeding and release suggests that the animals were able to resume aspects of their natural habitat use.
