Black rhinos were hunted to near extinction, and, by 1930, there were only 110 left in the wild in South Africa. This prompted an ambitious relocation programme.
By spreading rhinos around the country, wildlife officials not only helped increase rhino numbers, but also helped to bolster genetic diversity - vital to the preservation of the species.
DNA test results released by Stellenbosch University show that the policy worked. The data werepublished last month in the scientific journal Animal Conservation, the official publication of the London Zoological Society.
The publication coincides with the release of the latest national black rhino population figures, showing that their numbers have risen to more than 2000 in South Africa.
However, according to the International Rhino Foundation, there were 65000 of the animals in Africa in 1970. The World Conservation Union puts rhino figures in Africa today at 4300.
International Rhino Day was celebrated around the world this week, with much of the focus on efforts to prevent the poaching of the animals in South Africa.
Researchers tested 77 rhino samples, collected during the process of rhino tagging, when small pieces of the animal's ear are removed.
Complex molecular testing shows that the local black rhino population is more genetically diverse than expected, given the animals' common ancestry.
The greater the genetic diversity, the better the chances of adapting to a changing environment, scientists say.
Minette Karsten, one of the researchers, said the rhino study was the first of its kind.
"Our findings pay tribute to the well-managed and well-documented efforts of the KZN conservation officials, who, over the past 40 years, have had the survival of South Africa's black rhino populations at heart," she said.
"Our aim was to provide scientific information that can support the management and monitoring of this rare species.
"We hope this will, along with other ecological data, assist any future decisions about translocation of rhinos between reserves in SA and between various countries."
The conservation success story is in stark contrast to a recent upsurge in rhino poaching, which has claimed 287 rhinos in South Africa so far this year.
Last year, 333 rhinos were killed for their horns, used for medicinal purposes in Asia.
The surge in poaching has prompted some private reserves to consider injecting an "anti-parasite" solution - which is known to be harmful to humans - into rhino horns.
Dr Peter Goodman, co-ordinator of biodiversity research in Ezemvelo KZN Wildlife's biodiversity research division, said the Stellenbosch study would bolster rhino conservation efforts.
"We are grateful to know that our [relocation] strategy thus far has been shown to be scientifically sound," he said.