VN March 2023

Vetnuus | Maart 2023 12 The 1800s saw the lowest recorded population of Southern White rhinos, with between 20-50 individuals left in a single population in Hluhluwe-iMfolozi in Kwazulu Natal. Frederik C. Selous said, “some few white rhinoceroses no doubt still survive, but it is not too much to say that long before the close of the century, the white rhinoceros will have vanished from the face of the earth”. As the pressure of uncontrolled hunting and habitat threats continued to threaten the population, some brave conservationists granted the single remnant population protection in the Umfolozi Junction Reserve in 1895. The population had a rapid initial growth and was over 400 strong by the early 1950s. In the 1960s, “Operation Rhino” was introduced to facilitate the relocation of SWR to other protected areas, such as the Kruger National Park, to attempt to reintroduce animals to these areas. Due to the continued conservation efforts and the commitment of stakeholders, the population in the Kruger National Park were said to be over 9000 strong in 2017 and is currently the largest single population of white rhinos. A few years after the bottleneck that almost led to the extinction of the species and the recovery of the population numbers, white rhinos are faced again with immense pressure from poaching, and the population of white rhinos decreased by 15% between 2012 and 2017. The increase in poaching in National Parks resulted in direct pressure on the government to implement measures to combat poaching. In an attempt to relieve financial pressure on the government, the decision was made to mitigate the risk of poaching by exploring the possibility of establishing populations outside of the Kruger National Park. Several rhinos were moved to smaller reserves and sold to private wildlife farmers who continued farming these animals on their private farms. The translocation of these rhinos led to new populations that are self-sustaining and can lead to an increase in species numbers. As the populations in private farms grew, the need for conservation genetics was highlighted. Conservation genetics primarily focuses on the genetic factors that may threaten the population. Genetic diversity within a population, and in large a species, confers to the ability of the population to survive changes in the environment and further adapt to new environments. Thus, maintaining sufficient diversity within a population is paramount to ensure its longevity. Maintaining enough genetic diversity further reduces the risk of inbreeding depression in the population. Inbreeding depression refers to the detrimental effects that inbreeding may have on a population and can lead to, for example, lower fertility rates, reduced juvenile survival, harmful mutations and, as a whole, a reduction in population size. The bottleneck of the white rhinos in the 1800s led to an overall limited gene pool and, therefore, further accentuated the need for captive breeding programs to include genetics in managing the population. Captive breeding programs should aim to maximise genetic diversity within the population to improve the population’s chances of survival. Several techniques are available to manage the genetic diversity of the population effectively. A pedigree analysis involves tracking the ancestry of each individual within the population and analysing the family tree of the population. By doing this, breeders can identify less related individuals and select breeding between these individuals. This will reduce the risk of inbreeding and may subsequently increase the genetic diversity within a population. Breeding for a better future: Why the genetics of rhinos are important for their survival Jodea Marais (M.Sc. Conservation Genetics) Article Figure 1: A case study on two populations of white rhinos farmed in South Africa showed that the highest amount of genetic diversity seen is in individual animals, with 28% genetic diversity within the populations. 0% diversity was seen between the two populations, suggesting low overall genetic diversity within the species.