Pretoria - Saving South Africa’s lions has come at a price – inbreeding, disease and loss of genetic diversity. But a new DNA project hopes to unravel their bloodlines to help ensure their future.
Two decades ago, 100 000 lions roamed Africa. That number has plummeted to “somewhere between 20 000 to 40 000”, says Susan Miller, a Canadian doctoral student in nature conservation at the Tshwane University of Technology.
Miller and fellow researchers – including Dr Cindy Harper from the Veterinary Genetics Laboratory at the University of Pretoria, famed for her work in the DNA profiling of rhino horn – are exploring the pride dynamics and genetic integrity of isolated lion populations across South Africa.
“If you were to increase the habitat of lions in the rest of Africa twofold tomorrow, the lions would fill the space because they breed so effectively,” Miller said at De Beers’s third annual Diamond Route research conference this week.
“Lions breed like rabbits. The problem in the rest of Africa isn’t a lack of lions. It’s a lack of space because of human encroachment.
“In South Africa, they’ve kind of got around this by putting up fences. But fences create different challenges. Overpopulation is a big problem. These smaller reserves have almost got too many lions and don’t know what to do with them. There’s also the potential for inbreeding.”
About 45 percent of South Africa’s free-roaming lions are confined to small fenced reserves, where isolated lion populations are often “micromanaged”, their natural movements are cut off and the potential is high for inbreeding and disease.
That’s why Miller is examining lion DNA, using 26 microsatellite markers from more than 250 blood, hair and tissue samples taken from all of South Africa’s lion groups.
“It’s been recognised that there are a few populations in trouble and work is being done to sort it out. But until we look at our data, we just don’t know the levels of genetic diversity. You can’t make conservation plans until you know what the level of inbreeding is.”
Consider the lions of the Hluhluwe-Umfolozi Park in KwaZulu-Natal, which originated from a founding population of just three individuals – so the 120 lions are “exceptionally inbred”. In 1999, the reserve started a project to introduce new blood.
“You can fix it relatively easily by bringing in more lions from another population But if you do that too many times you’re going to lose the overall genetic diversity.”
Inbreeding reduces sperm motility and viability.
“You can get physical defects. Generally the lions will be less reproductively fit. It can also lead to less ability to combat disease.
“If you have clones of lions, they’re all genetically identical, and one disease could wipe out everybody. But if you have lions from different genetic backgrounds, maybe 10 percent would die from a disease and the others would survive.”
Miller’s research has also found that lions that roam De Beers’s Venetia-Limpopo Nature Reserve boast valuable genetic markers not found in other lion populations, which could contribute to the genetic diversity of local lion populations.
Ultimately, Miller’s study, which she hopes will be completed next year, is towards the creation of a national management plan to link all lion populations in the country, simulate natural movements and reduce inbreeding.
Lions still face poaching, feline tuberculosis and persecution by farmers. But genetics is key. “We don’t know enough about the genetic diversity of our lion population… If you want to have lions in South Africa 100 years from now, if we don’t look after the genetics now, it will catch up with us.” - Pretoria News