Africa Wild

The Short-term (10 year) Conservation Goal will attempt to achieve the following population targets of:

- An average South African meta-population growth rate for both of the two indigenous subspecies of black rhino of at least 5% per annum, and
- Meta-population sizes in South Africa of at least 2,800 for D. b. minor and 260 for D. b. bicornis by the end of 2020

These will be achieved via the following six Key Components
- Biological Management will endeavour to achieve sustainable meta-population growth through a harvesting regime of 5% per annum where required; maintenance of a genetically diverse population, establishment of new populations, and management of surplus males via various means, inclusive of limited and regulated hunting of bulls.
- Population monitoring will be employed to provide accurate and precise information on black rhino populations to allow management to make informed decisions.
- Protection remains a key activity to minimize losses of rhinos from illegal activities and will be achieved through effective law enforcement, improved neighbour relations, effective criminal investigations and prosecutions, and securing and monitoring rhino horn stockpiles.
- Coordination of conservation management of black rhino populations through the reformalization of the South African Rhino Management Group (RMG) (see Appendix 1) an d development and implementation of rhino conservation plans by all conservation and private
owners with black rhinos.
- Human Resources will be assessed and developed to provide the required skills to protect and manage black rhinos.
- Economic & social sustainability of the programme also needs to be addressed to ensure political and social support for rhino conservation efforts.

5.1.2.1 Harvesting for Growth
Current population theory suggests that unless the carrying capacity (or zero growth population density) is declining, or removals exceed maximum potential growth rates, by harvesting at a fixed rate per annum, the population should respond by growing at least at that rate (see Appendix 4 for details). Thus, by removing at least 5% annually from established populations we are attempting to ensure that remaining animals in these populations continue to grow at least at this predetermined target rate. Harvesting also provides rhinos that can be used to set up new populations with the potential for rapid population growth. Thus harvesting is a win-win strategy, which should both maintain or enhance population vigour in the harvested population whilst also enhancing overall meta-population growth. Should rhino carrying capacity (zero growth density) change in populations being managed using set % harvesting, rhino densities should simply adjust to a new higher or lower level that can support the given % removal. On the other hand, a failure to reduce densities of populations approaching or above zero growth densities by at least 5%/annum is likely to negatively impact on habitat and ultimately reduce population growth rates to below minimum target levels. Thus:
- For established populations (especially large ones) that are showing a zero growth population density (or have exceeded 50% of estimated ecological carrying capacity), an annual minimum 5% harvesting strategy should be instituted.
- Actual removals from smaller populations would be determined by specific demographics and logistical requirements but still aiming to average at least 5% over a number of years or aiming to prevent the population exceeding 75% of estimated ecological carrying capacity.

5.1.2.5 Surplus Males
In the context of managing black rhino populations, notably smaller ones, the demographic skewing of the population sex ratio in the favour of males is likely to occur. This can have a negative impact on the population's breeding performance and genetic status. These bulls are commonly known as 'surplus males'. Thus:
- The surplus male problem is addressed through a number of means such as translocation, establishing male only groups, and hunting.
- The hunting of black rhino males is managed via a strict permit application process under the auspices of the national Department of Environmental Affairs who currently allocate the hunting tags up to the maximum CITES approved quota of five animals per year (the same as Namibia). This process has the support of CITES and the AfRSG. An RMG working group also developed a set of assessment criteria to ensure that only proposed hunts that will enhance demographic and/or genetic conservation should be approved. Should evidence and further modelling indicate that this quota should be increased to more adequately deal with the surplus male problem given continued growth in rhino numbers, South African authorities should consider submitting a proposal to a future CITES Conference of the Parties (CoP) to increase the annual quota. (See Appendix 6 for more details).
- As an alternative to hunting, establish male-only populations (preferably with young males that know each other) avoiding areas suitable and large enough for a larger breeding population.
- While it may not prove popular with recipient populations, consideration could be given for a limited period to "dumping" some surplus males into unoccupied areas in very large parks currently stocked well below ECC.
- Provide surplus males to intensive management institutions (Zoos and Safari Parks) worldwide in exchange for support of in-situ rhino conservation programmes. However, be aware that captive breeding institutions also have a surplus male problem and are trying to send males back to Africa.

The debate about rhino hunting
(Richard Emslie, Scientific Officer IUCN SSC African Rhino Specialist Group, written in 2005 for the EAZA Rhino Campaign 2005/6 Info Pack)

Black rhino hunting
The 13th Conference of the Parties (CoP13) of the Convention in Trade in Endangered Species of Fauna and Flora (CITES) from 2-14 October 2004 in Bangkok, Thailand also recently approved quota applications by Namibia and South Africa each to sport hunt five surplus male black rhinos per year.

At first glance, it seems inconceivable that anyone would want to hunt Vulnerable (Namibia) and Critically Endangered (South Africa) subspecies of black rhino when so much effort is going into protecting these animals and breeding them up as rapidly as possible.

The surplus male problem
The problem of surplus black rhino males is not new and has been discussed as far back as 1992. It is primarily the result of some black rhino populations ending up with markedly skewed sex ratios in favour of males. These skewed sex ratios can occur either by chance in some populations (with many more males than females being born in a population), or if removals from donor populations are biased in favour of females (as was the case in setting up the highly productive Namibian custodianship populations). The problem is compounded by an apparent slightly skewed sex ratio at birth in favour of males, although this is often later reversed because of the higher adult male mortality rates due to fighting.

The social carrying capacity of adult male black rhinos is also limited. If no action is taken in markedly male-biased populations, fight-related mortalities are likely to increase once these surplus males grow up. If surplus males killed only other males then perhaps they could just be left to fight it out and let natural selection take its course. However, conservationists have expressed concern that in such populations, valuable breeding females and calves may be injured or even killed as well as other males, as appeared to have been the case in Pilanesberg National Park in the past.

Surplus males also use valuable food resources that may affect female breeding performance. Although not yet conclusive, preliminary evidence from annual SADC Rhino Management Group status reporting suggests that female reproductive success may also be slightly higher in populations with a higher proportion of adult females to males. Thus many field managers in southern Africa have for some time now sought to find a way to reduce the number of surplus males in such populations. Somewhat counter-intuitively, the hunting of a limited number of surplus males may end up stimulating metapopulation growth rates and hence overall rhino numbers.

Only some populations have a surplus male problem. Owners or management agencies conserving populations that end up with skewed sex ratios in favour of females over males are invariably happy for this to remain the case as long as possible, as percentage growth rates and calving production will be higher. This is similar to productive cattle farming, where the number of bulls in a herd is limited to maintain rapid population breeding rates. Managers of such female-skewed black rhino populations are simply not keen to accept males.

The corollary is that while populations that end up with markedly skewed sex ratios in favour of males usually want to obtain more females, sourcing additional females is very difficult. Many donor populations, not unexpectedly, are loath to provide females only, as this would negatively affect the donor population’s sex structure and potential future performance. In practice, it is hard for the populations that have by chance ended up with more males to source and obtain additional females.

It is also known that specific rhino males can dominate the breeding and sire a large proportion of the calves in smaller populations. The removal of such animals after a period of say 10–15 years may therefore reduce the risk of father–daughter matings and contribute positively to the genetic management of such populations, in the same way that a cattle farmer is unlikely to keep the same breeding bull for an extended period. In addition, the hunting of an old post-reproductive male that has been pushed out of his territory will not affect his contribution to the gene pool of that population.

Attempted solutions to the surplus male problem
A number of alternatives to hunting surplus males have been tried over the years including sending them to zoos, attempting to sell surplus males, and creating male-only populations in reserves that are too small to hold breeding populations. This last approach has not been particularly successful or popular. For example, in Makasa, KwaZulu-Natal, South Africa, a bull in a small male-only population killed the other two males. For the approach to have a better chance of success, it is recommended that males that “know” each other be introduced together.

Attempts to exchange or introduce adult males to bring in new blood to populations have also not had much success, with the result that it is recommended that adult females be introduced instead.

The argument that surplus males can be used to “test” potential new areas for reintroduction also has limited applicability. This is because breeding females need to be on a higher nutritional plane than males successfully to conceive and raise calves at a rapid rate. A “survival” diet for a small number of male rhinos is not the same as a diet for optimal breeding. Therefore, the mere fact that a few surplus males survive in a new area is no guarantee that females will breed well if introduced (which in the process will raise stocking rates higher).

In addition, mortality risks when setting up new populations appear to be reduced if founder animals are introduced at the same time. Concerns have been expressed by some that if males-only populations were to be established, and females introduced at a much later date, mortality rates of females following introduction may increase. If an area is big enough to set up a breeding population of black rhinos, ideally one should proceed straight to setting up the breeding population and not start with males only. If one starts with males, the problem remains of sourcing more females than males in future.

Demand for surplus males has been limited, and as a result these males have not generated much revenue to help fund conservation. Live males auctioned in KwaZulu-Natal in 2004 fetched an average price of US $21,130.