Translocations

History of translocation in Saudi Arabia

The NWRC has been responsible for the captive breeding and reintroduction of Arabian oryx in Saudi Arabia since 1986. Arabian oryx have been re-introduced into two protected areas: between 1990 and 1993, 72 oryx were released to the fenced Mahazat as-Sayd protected area, and since 1995, 149 oryx have been released into the 'Uruq Bani Ma'arid protected area in the Empty Quarter. More than 95% of released animals were mother-reared. Care is taken to minimize contacts with human beings during the breeding season in order to prevent captive-bred oryx from atypical biased behaviours. Special procedures are carried out at the NWRC to successfully select, prepare, and release these white antelopes into the wild.

Genetics of animals chosen for reintroduction

In order to achieve maximum genetic diversity in the released herd, pairs that produce reintroduction candidates are chosen according to their genetic lineages. Founder representation is estimated for the current population in the reserve, and is calculated for the oryx to be re-introduced. Projections are prepared a minimum of two years in advance of the planned release. All the selected candidates are negative for a number of diseases and for the 18-19 Robertsonian chromosomal translocation.

Boma training

The trip from the NWRC to 'Uruq Bani Ma'arid protected area takes seven to nine hours of road, and air transportation, and is stressful for the animals. To reduce this stress, oryx are "boma-trained" for one month before the transportation. They are daily and progressively familiarized with being pushed through corridors, restrained in a narrow crate, and transported on the road. The oryx are transported in communal crates, and the social structure within groups of four/five oryx is established at least two months before transportation. Age, sex-classes, and compatibility of individuals determine the structure of the groups. Animals that were raised together are kept together for the translocation. Three days before transportation, the oryx may be injected with a long acting tranquilliser (Perphenazine enanthate), depending on their nervousness.

Soft release

At reintroduction sites, a soft-release method is used. On their arrival in the protected area, the oryx are initially kept in a small pen (2-3 days), and then moved in a pre-release enclosure, where they remain for a minimum of one month. Food and water are provided ad libitum. During this transition period they acclimate to their new environment, often express some territorial behaviour, and probably adjust their gut flora. The pre-release period also allows the NWRC staff on site to visually check the health status of the oryx. When forage conditions are considered adequate, the oryx are released in the reserve and food and water provisions are stopped.

Results

Effectiveness of the reintroduction procedure is regularly evaluated. So far, no deaths occurred during the transportation of oryx in the 'Uruq Bani Ma'arid protected area.

Reintroductions

Mahazat as-Sayd Protected Area in central Saudi Arabia

Reintroduction site

The first area chosen for Arabian oryx reintroduction in Saudi Arabia was the 2,244 km² Mahazat as-Sayd protected area, 160 km northeast of Taif. Mean annual rainfall in the area is less than 100 mm while air temperature often exceeds 45ºC during summer. In 1989 the entire reserve was fenced to exclude grazing livestock.

Translocations

Between 1990 and 1993, 38 Arabian oryx from foreign, private or national collections and 34 oryx from the captive-breeding unit at the NWRC were moved to the reserve, held within a 200-ha enclosure, and then released into the protected area.

During 2005, eight Arabian oryx (6 males and 2 females) were translocated to the Mahazat as-Sayd Protected Area. Due to the poor representation of the Qatari and Bahraini lineages in the free-ranging Mahazat as-Sayd oryx population, Ostrowski and Mésochina (2005) proposed that these eight oryx from the NWRC be reintroduced into the protected area to improve the genetic make-up of this population (Anajariyya & Muhammed 2005).

Monitoring of the reintroduced herd

During 1990-92, a team of rangers under the supervision of the reserve's manager tracked and located oryx daily. As the population grew and animals dispersed into many small groups it became increasingly difficult to account for all of the oryx each day. Since May 1995 regular transect surveys have been carried out in the reserve. Between 1990 and 1997, the population increased steadily up to about 400 individuals. In 1998 and 1999, because of severe drought conditions, the population levelled off around 350-400 individuals. Good rainfalls, and therefore enhanced forage conditions in 2001 and 2002 allowed the population to recover. By May 2002, the population was estimated to have reached about 500 individuals [Mésochina, pers. com.].

Population dynamics

Because the reserve is fenced, emigration and predation are not limiting the oryx population growth. We have recently developed a computer model that evaluates the probability of extinction of the Mahazat as-Sayd oryx population under various management strategies [Treydte et al., 2001]. The most successful management plan consisted of removing every year all oryx above 70% of the carrying capacity. Management is required to avoid larger fluctuations of the population and to maintain the Mahazat as-Sayd oryx population within the limits of a desirable population size.

The return of the Arabian oryx to the "Empty Quarter"

Reintroduction site

Following the successful establishment of a self-sustaining oryx population in Mahazat as-Sayd, the NCWCD/NWRC undertook the reintroduction of Arabian oryx into the 'Uruq Bani Ma'arid protected area. This protected area covers approximately 12,000 km² at the western edge of the Rub' al-Khali desert (in English 'Empty Quarter'), one of the driest regions in the world. Mean annual rainfall is less than 50 mm while air temperature may exceed 50ºC in summer. Rainfall is unpredictable both spatially and temporally (coefficient of variation from year to year is higher than 80%). Ungulates vanished from the area as a result of over-hunting. According to local people, oryx and sand gazelles were seen at the edge of the western escarpment as recently as the 1960s. This is probably due to the relatively good vegetation found in the wadis at the escarpment edge.

Translocation

Since 1995, when the first releases took place in the 'Empty Quarter', 17 groups of Arabian oryx for a total 149 oryx (70 males, 79 females) have been transported in the protected area. A total of 141 of these animals were captive-bred from the NWRC, whereas 8 came from the Mahazat as-Sayd protected area.

A group of six (2 males, 4 females) wild-born oryx were transferred from Mahazat as-Sayd to Uruq Bani Ma’arid protected area on 7th May 2006 after a karyotype screening to verify the chromosomal translocation. The test was made by the KKWRC, Thumamah and all these individuals did not have any chromosomal translocations (Anajariyya & Muhammed 2006).

All animals were identified with numbered tags and fitted with Radio collars. The capture and transportation procedures were well organised with no accidents recorded. Prior to departure the animals were treated with Antibiotic and multivitamins as well as de-wormed with Ivomec (Anajariyya & Muhammed 2006).

Monitoring and population dynamics

Mortalities among reintroduced and wild-born animals have been recorded in the reserve since the first arrivals. By mid 2002, we estimated that 28 % of the re-introduced animals died, and 13% of them have had an unknown fate. Thirty percent of mortality had unknown reasons. Main causes of known death were starvation (65%) during the four years of drought (1997-2000), fights between males (19%), and poaching (13%). However, monitoring carried out by the NWRC staff indicates a sustained population growth. Productivity of the released animals is still satisfactory, and although the area received less than average rainfalls in 1998 and 1999, animals are currently doing well. By August 2002 the population of free-ranging oryx was estimated to number 160 to 200 animals.

Rawdat Al-Kharim Reserve

A total of 27 oryx (5 males and 22 females) were transferred from the NWRC captive herd in January and February of 2005 to the Rawdat Al-Kharim reserve in Riyadh. The capture and translocation procedures were well organised and no accidents occurred. Finally, a group of 10 oryx (3 males and 7 females) and another group of six oryx (2 males and 4 females) were translocated to the farms of Prince Sultan bin Abdulaziz and Prince Bandar bin Abdulaziz in Riyadh respectively (Anajariyya & Muhammed 2006).

References

Anajariyya & Muhammed 2005. Arabian Oryx – Captive Breeding - NWRC Annual Report 2005, unpublished report.

Anajariyya & Muhammed 2006. Arabian Oryx – Captive Breeding - NWRC Annual Report 2006, unpublished report.

Chassot, P., 2004. Field Biologist’s report in ‘Uruq Bani Ma’arid – NWRC Monthly Report for December 2004, unpublished report (22pp).

Ismail, K. & Strauss, W. M. 2005. Ungulate monitoring in Mahazat as-Sayd Protected Area - NWRC Annual Report 2005, unpublished report.

Ismail, K. & Strauss, W. M. 2006. Ungulate monitoring in Mahazat as-Sayd Protected Area - NWRC Annual Report 2006, unpublished report.

Strauss, W. M. 2006. Arabian oryx and Sand gazelle monitoring in Mahazat as-Sayd Protected Area – NWRC Annual Report 2006, unpublished report.

Strauss, W. M. 2005. Uruq Bani Ma’arid Protected Area – NWRC Annual Report 2005, unpublished report.

Strauss, W. M. 2006. Uruq Bani Ma’arid Protected Area – NWRC Annual Report 2006, unpublished report.

Wacher, T.J., 2006. Monitoring Results: Uruq Bani Ma’arid; August 2006. King Khalid Wildlife Research Centre Gazelle Reintroduction Programme, unpublished report (12 pp).

White, G.C., 1996. NOREMARK Software Reference Manual. Department of Fishery and Wildlife, Colorado State University. (34pp)