Du Toit, R., 1994. Management of black rhino in Zimbabwean conservancies: pp. 95-99
 | In: Penzhorn, B.L. et al. Proceedings of a symposium on rhinos as game ranch animals. Onderstepoort, Republic of South Africa, 9-10 September 1994: pp. i-iv, 1-242 |
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| Location: |
Africa - Southern Africa - Zimbabwe |
| Subject: |
Distribution - Records |
| Species: |
Black Rhino |
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Diceros bicornis. Of the 260-300 black rhinos still surviving in Zimbabwe, about 160 (55-60%) are on private land. These are the survivors and offspring of groups of rhinos (totalling 189) which were translocated mainly from the lower Zambezi Valley and mainly over the period 1986-1988. Prior to these translocations, the only black rhinos on private land were a few that strayed through ranches adjacent to wildlife reserves in the Doma area (northern Mashonaland) and the Matetsi-Gwayi area (northern Matabeleland).
The rhinos were translocated by the Department of National Parks and Wild Life Management (DNPWLM) in accordance with one of the four objectives of Zimbabwe's Black Rhino Conservation Strategy; the relevant objective is ?to develop translocated breeding nuclei elsewhere in Zimbabwe (i.e. outside the Parks and Wild Life Estate) and to maintain their genetic variability'. The rhinos were moved to private land areas largely because there are no national parks, safari areas or other areas of State Land away from the national borders (and therefore less prone to incursions by Zambian poachers), which have suitable habitat and are adequately fenced to hold free-ranging black rhinos. In addition, DNPWLM faces a fundamental problem of insufficient manpower and funds to protect the extensive rhino ranges under its jurisdiction. Hence, any translocation of rhinos to other areas of State Land would merely aggravate this problem, by spreading the anti-poaching resources even more thinly.
The selection of private properties to receive black rhinos initially followed a somewhat arbitrary procedure, largely dependent upon the degree of interest which landowners displayed in acquiring these animals. As will be discussed, a number of problems have arisen as a result of this excessively ad hoc distribution process, but the overall programme has proved to be relatively successful.
After poaching losses, natural deaths, and some redistribution of rhinos, the number of private land areas with black rhinos has decreased from 14 to 10; these areas now fall into three rhino management categories.
Intensive management facilities. These are small properties on which semi-tame rhinos are maintained through artificial feeding. There are two such properties: lmire Game Park (Hwedza area) and Chipangali Wildlife Orphanage (Bulawayo area). The rhinos were hand- raised, following deliberate separation from their mothers during capture operations in 1986 and 1987 (this practice has been discontinued). It has become apparent that there are serious constraints to the breeding of rhinos in these situations.
Major breeding areas. Through direct translocations from State Land, and through redistribution of rhinos on private land during 1993, two relatively large breeding groups have been built up: 39 rhinos in the Save Valley Conservancy (south-east Lowveld) and 44 in the Bubiana Conservancy (West Nicholson area). These areas are showing good progress towards becoming Zimbabwe's 'rhino factories'.
Satellite breeding areas. The other black rhinos on private land are in six separate groups of 2 - 29 animals. Unlike the large Lowveld conservancies, most of these areas are unable to carry significantly more rhinos, and there are inbreeding risks, so it is necessary to periodically move offspring to other areas.
Conservancies
The formation of 'rhino conservancies' in 1991 was a response to security problems as well as to the rhino management problems outlined above.
To create a viable breeding group of black rhinos, it is obviously essential to have an adequate number of animals with a reasonable sex ratio, living within a sufficiently large area of suitable habitat, to permit rapid expansion of the founder population.
Computer simulation models' show what is likely to happen if rhinos, as a long-lived species with a relatively slow rate of reproduction, are reduced to small isolated populations (with under 30 in each). Such models suggest that these populations would have a good chance of expanding and surviving for long periods despite some reduction in population growth rates due to inbreeding depression and random fluctuations in sex ratios, age structures and other demographic factors. However, if each of these small populations is unable to expand owing to inadequate carrying capacity or poaching, genetic variation within the populations will be rapidly eroded through inbreeding and other genetic processes, and the species will not only lose its capacity for continued adaptive evolution but will eventually accumulate lethal genetic traits and die out. Hence, some simple principles to follow in setting up a rhino breeding programme are:
- start each breeding group with 30-40 founders;
- allow these to expand as rapidly as possible to over 100 through uninterrupted breeding;
- periodically exchange breeding animals between some separate breeding groups (i.e. maintain 'metapopulations' through regulated gene-flow).
To prevent density-dependent constraints on population growth, a maximum stocking rate of 1 black rhino per 10 km? is prudent for the Lowveld areas, reducing to 1 per 15 km? for the Midlands.
None of the individual ranches which received black rhinos is large enough to carry a founder group of 30 rhinos which could expand to over 100 (at a stocking rate of no more than 1 : 10 km? ). It was therefore necessary to amalgamate groups of ranches to form suitable refuges, each totalling over 1000 km? in extent. Hence the formation of the Lowveld 'rhino conservancies'.
As regards security, the pressure of commercial rhino poaching activities requires a comprehensive, well co-ordinated antipoaching programme, instead of the disjointed efforts of individual custodians of black rhinos. The staffing and equipping of antipoaching units is easier and less costly if done as an overall conservancy initiative. The more properties involved, the tighter will be the overall detection screen and the quicker will be the reaction to any poaching incursions. Apart from these advantages in terms of conventional antipoaching, conservancies have the potential to achieve constructive interaction with neighbouring Communal Land communities through mutually beneficial projects. They can thereby develop incentives for local people to report rhino poachers.
The future
It would be overly ambitious to suggest that all rhino poaching in conservancies can be curtailed. There are bound to be opportunistic forays by commercial poachers, and snaring by subsistence poachers, leading to the loss of some rhinos. However, there are encouraging indications that a holistic approach will ensure that the poaching attrition will be kept to a level which is below the natural growth rate of the rhino populations. As far as biological management issues are concerned, the initial mistakes that were made in the placement of rhinos on private land are being corrected. Following this experience, the natural growth rate and genetic diversity of rhino populations in conservancies can now be maximized through the interactive management of the large breeding groups and the satellite breeding groups.
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Management of black rhino in Zimbabwean conservancies
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