1981-1995, annual mortality averaged 3.6 %. But in first 6 years after release there was no mortality, in subsequent 9 years mortality averaged 6 %.
1996, 42 animals present Ranges in 1996 on figures: adult females F 1, 5, 9, 13, 18, 27 Young adult females: F 4, 6, 10, 11, 12, 14, 17, 19, 30, 32 Adult males in 1991: M 8, 16, 21, 23, 25, 26, 29, 31 - 8, 24, 26 have since died <1996 Young adult males in 1996: M 3, 7, 15, 16, 23 F32 died in 1994
Release in Pilanesberg NP. Range sizes seem to depend on age and sex. Range size was estimated from the area enclosing most sightings, i.e. excluding those outside the usual range of the rhino. Also hills judged to be unusable (too steep, or without the normal food plants) were excluded from home range calculations. Female ranges were larger on average than male ranges. Adult females gave 10% to 60% range overlap. Sub-adult females range more widely than adult. Once they approach adulthood, they seem to settle down in a smaller, more defined area to have first calf. The range sizes of these young adult females are similar to those of older females. Adult males over 15 years of age have little range overlap. This points at territory: Territoral behaviour of adult males: Only one mature male occupies a given range Males demarcate the territories by urinating and scraping dung piles Fighting is a major cause of death among male rhino. The male range is keyed to permanent water supplies. Subadult and young adult male ranges overlap those of adult bulls. The young males (up to age 8) are tolerated by mature bulls. Males from 8-10 yrs old and onwards, they wandered further afield than before, their ranges still overlapping each other and those of old bulls. It is supposed that by this age the males still have not established their home range or territory. Home range sizes In Pilanesberg independent subadults female 63 km? male 35 km? Young adults female 48 km? male 36 km? Adults Female 52 km? male 28 km? In other reserves, not adjusted for age or sex: Ndumu GR 8.65 km? Weenen NR 10.00 Sam Knott GR 11.54 Shamwari GR 15.00 Mkuzi GR 24.00 Lapalala GR 40.00 Itala GR 49.00 Waterberg Plateau NP 60.00 Etosha NP 60.00 End
1996 June, 9 black rhino translocated from Pilanesberg
1983, 19 had been introduced from Hluhluwe/Umfolozi
Release in Pilanesberg NP - Diceros bicornis. It was noted in 1981-83, that the rhinos released without on-site boma keeping were highly disturbed, which increased the rate of these new animals encountering and fighting previously introduced rhino.
- release in Pilanesberg NP. The experience from Pilanesberg suggests that there is a limit to the number of males an area can carry.
1989, 5 came from Mkuzi, 3 males died, 2 females survived.
Release in Pilanesberg NP. Male black rhino seem to mature socially later than females. In Pilanesberg, female calves become independent of their mothers at a younger age than males: average for female young 2 yrs 1 mo 4 females average for male young 3 yrs 7 males average for both sexes 2 yrs 9 mo Subadult males are frequently seen with their mother beyond 3 years, while females wander more, and associate with other mature females, but only occasionally with their own mother.
The black rhino introduced 1981-1983 were monitored by Hillman. 1984-1989 only annual game census by helicopters were done. In 1989 monitoring efforts were increased. Hansen and lindemann were contracted to initiate, and later update individual rhino ID-kits in annual intensive helicopter and ground surveys. In 1991 an ear-notching programme started, which means that all animals are individually recognisable. In 1984 a black rhino monitoring officer was appointed.
Park covers 550 km?
1979, Pilanesberg National Park was proclaimed
The park has rocky hills and broad alluvial valleys in a weathered alkaline volcano. The summer rainfall averages 637 mm annually.
Adult males over 15 years of age have little range overlap. This points at territory: Territorial behaviour of adult males: Only one mature male occupies a given range Males demarcate the territories by urinating and scraping dung piles Fighting is a major cause of death among male rhino.
Average population growth has averaged 5.77 % per year. Growth rate elsewhere in South Africa range from -8.9 to +11.3 %.
Release in Pilanesberg NP - Diceros bicornis. Excess male black rhino should ideally be removed from a population to promote population performance in restricted areas. However, these surplus males cannot easily be placed in established populations [stress and intolerance from other males]. Male-only sanctuaries could be set up, but this is expensive and wasteful, as funds and land for translocation to start new breeding populations of black rhino are at a premium. Few private landwoners are prepared to pay for animals that are expensive to protect and can only be used for tourism. In 1990, the benefit of hunting surplus males, preferably old or aging, was put forward. In this way, excess males could be removed to the benefit of black rhino population performance by generating income for the required intensive security and monitoring. Unfortunately, international issues have prevented this solution from being adopted so far. Still, surplus male rhino has become a critical issue in most black rhino conservation areas in South Africa and elsewhere.
Release in Pilanesberg NP - Diceros bicornis. For introductions 1981-83, the animals were not kept in bomas before or after transport.
Reported rhino densities in South Africa Black rhino per km? 0.218 No.of rhino 120 0.109-0.145 60-80 0.145-0.1818 80-100 0.105 50-100 0.96 50 In Pilanesberg: Density was 0.076 per km? for population level of 42 reached in 1995. If only suitable black rhino habitat (60% of the park) is considered, maximum density was 0.15 per km?.
Release in Pilanesberg NP - Diceros bicornis. Out of 19 initial reintroductions 91981-83), only 2 males were subadult on arrival, which may have played a significant role in the success of these initial reintroductions. In 1989, 5 subadults (3/2) were brought, and the 3 males, aged 15-27 months, all died within months of release from fighting injuries in one case, and stress and harassment of established rhino for the others. The females settled down successfully. This has highlighted the vulnarability of young rhino. They become more stressed after introduction into a new area than older rhino, they are not able to defend themselves, and are not adept at finding the right food, water and cover.
Release in Pilanesberg NP - Diceros bicornis. Males seemed less inclined than females to explore remote parts of the reserve. Males settled in the main valleys near the release sites, while females found ranges in suitable areas throughout most of Pilanesberg.
Release in Pilanesberg NP - Diceros bicornis. During the early introductions, the abundant space available to the rhino meant that when conflicts arose, there was room to escape. This probably played a role in the success of these early staggered reintroudctions. Subsequent changes in rhino ranges showed that the animals were not truely established until at least 3 years after release. For later introductions, the established male density was likely a negative factor. Although the total rhino density was only 60 % of ecological carrying capacity, there were 8 adult rhino which commanded water and food resources, leaving little place for young rhino to settle.
Release in Pilanesberg NP - Diceros bicornis. The number of fighting incidents among the male deaths (5 cases out of 15) suggests that social pressure is a significant factor.
Pilanesberg NP. Average observed inter-calving interval is 34 months or 2.8 years. The most likely mode is 2.6 years, from 20 observations, range 2.1 to 5.8 years. Intercalving interval is thought to decline with female age, but there is no indication of this yet in Pilanesberg.
Males from 8-10 yrs old and onwards, they wandered further afield than before, their ranges still overlapping each other and those of old bulls. It is supposed that by this age the males still have not established their home range or territory.
Release in Pilanesberg NP - Diceros bicornis. In 1981-1989, 3 out of 24 animals died, is 12.5 %. Other figures: 6 % for Natal Parks board translocations 1962-1984 (Hitchins 1984) 8.4 % for all South African and Manibian translocations excl. Pilanesberg, 1986-1995 16 % in Kenyan translocations (Brett)
Release in Pilanesberg NP - Diceros bicornis. The experience from Pilanesberg suggests that there is a limit to the number of males an area can carry. Excess males should ideally be removed to pormote population performance in a restricted area. However, these surplus males cannot always be placed in established populations. Male-only sanctuaries are expensive and wasteful.
Release in Pilanesberg NP - Diceros bicornis. Although introductions occurred during a drought period, adaptation to the local food and habitat appranetly did not present a problem. The rhino's condition improved after release.
Pilanesberg NP. Annual monitoring demonstrated that black rhino are not fully grown (adult) until at least their 7th to 8th year. The Basal diameter of the rear horn (reflecting skull dimensions) stabilises after this age.
Pilanesberg NP. Average age of first calving was 7.5 years, range 6.8 to 8.8 for 7 females. Body weight is known to affect fecundity, and young rhino would need to approach 80% of their adult body weight before successfully conceiving, which is usually when the female is about 6.2 years old.
