New Genes in the ‘Pool’

Don’t you hate it when you’re hard at work fixing a leak in the bathroom pipe, and you discover that the tools needed to complete the job have somehow disappeared from your usually jam-packed toolbox? That’s exactly what’s happened to Africa’s cheetah population after declining by 76% over the last 100 years.

Just like where your tools go missing, when a portion of an animal population goes extinct, it also loses a portion of its genetic diversity. This results in what’s known as a “population bottleneck” and the few remaining individuals become similar in their genetic construct – what was once an assortment of tools becomes a small collection of hammers. Ultimately, this impacts the long-term viability of the population as it no longer has the “genetic tool kit” to adequately adapt to changing environmental conditions.

Up until 1965, cheetah were considered vermin by provincial legislation in South Africa. Despite their rapidly declining numbers, free-roaming cheetah were readily (and legally) killed by farmers who suffered animal stock losses as a result of predation. When farmers began to shift from cattle ranching to wildlife ranching and cheetah-farmer conflict escalated to a state of serious concern, a programme was instituted to remove cheetahs from commercial farmland and relocate them to small fenced reserves. By 2009, a total of 157 cheetah were removed from the free roaming population and introduced onto 37 different fenced reserves throughout South Africa – and the population began to decline.

Although the programme might have saved cheetah from angry farmers and stray snares, it reduced genetic diversity. Where free roaming cheetah were initially able to migrate between widely distributed pockets of cheetah populations, relocating them onto enclosed reserves restricted their dispersal and reduced gene flow. Now subjected to inbreeding, cheetah were more susceptible to genetic traits such as poor sperm quality, focal palatine erosion, susceptibility to similar diseases, and even kinked tails – all ramifications of the low genetic diversity within the global cheetah population.

In addition to low genetic diversity: predator-naïve cheetah being introduced into reserves with high lion densities, the sale of cheetah into captivity, single sex introductions, and excessive contraception programmes all contributed towards cheetah population decline. Unfortunately, as these smaller reserves are generally driven by financial objectives and have low predator carrying capacities, the majority of these issues were unavoidable. It had become evident that the haphazard cheetah reintroduction plan required refinement, particularly guidance by a long term conservation strategy that would help maximise the genetic diversity of the population.

In 2011, the Endangered Wildlife Trust (EWT) launched the “cheetah meta-population project”, which aims to facilitate a coordinated management approach to cheetah reintroductions on small reserves. The programme, which relocates cheetah individuals between 48 small fenced reserves, aims to mimic natural dispersal that may have taken place had the landscape not been impacted by anthropogenic factors such as fences, farms and settlements. This approach should ultimately maintain both the genetic integrity and demographic viability of the South African cheetah population. What’s more is that this initiative has helped restore cheetah populations in areas where they had become locally extinct – the Free State had not seen these fleet-footed carnivores for nearly 100 years before their reintroduction in 2013.

Cheetah were first introduced into Welgevonden Game Reserve in 1999 when a free roaming cheetah was brought in from the local farmlands. The population only began to grow upon the introduction of two female cheetah from Phinda Private Game Reserve in 2009. Five years later, there were 21 healthy cheetah residing within the Reserve’s boundary. As is the case with all fenced reserves, there is a limit to how many predators the area can sustain. When management noticed a stark decline in impala numbers, they turned to EWT’s programme.

Since 2014, the Reserve has relocated a total of 10 cheetah individuals to various private reserves, including Liwonde National Park in Malawi, and introduced 3 individuals to promote genetic diversity within the population. The latter number increased to four when a large, slender male was translocated from AmaKhosi Private Game Reserve on the 21st of September 2018, bringing a host of new genes with him. With only one male adult cheetah currently on the reserve, this additional individual will increase genetic diversity and help prevent inbreeding.

The male was released into a boma upon arrival, allowing him to acclimatise to the area before being released into the main reserve. He has also been fitted with a tracking collar which will help management monitor his movement patterns, interaction with other animals and his overall adaptation to his new home. This collar will be removed once he has successfully established himself on the Reserve.

“With only 3 adult cheetahs on the Reserve, it was important that we introduced this new adult male to increase the genetic diversity of the current population. The individual is “lion-weary” and should easily adapt to the environmental conditions at Welgevonden. All our introductions and relocations are carefully managed with the aim of maximising diversity while maintaining a suitable population size. We plan to relocate one of our sub-adult males to a different reserve once the opportunity presents its self” – Samuel Davidson-Phillips, Conservation Manager