In the Karoo, jackal and caracal favour micromammals such as Karoo bush rats and the four-striped field mouse, and will target these as a key part of their diet, even when there are sheep and goats available.
Many livestock farmers in the Karoo who have been losing sheep and goats to jackal and caracal have realised that night hunting, poisoning and trapping is not working. They have been waiting for other solutions.
Research conducted over three years in the Laingsburg district of the Karoo by the University of Cape Town’s Department of Biological Sciences, could offer an important key in the livestock predation battle.
The research area included 22 neighbouring sheep farms in the Laingsburg district of the Karoo and the Anysberg Nature Reserve, one of CapeNature’s reserves, situated southwest of the project farms.
Income similar to schoolteachers
Laingsburg is a marginal farming area. Rainfall is in the order of 120 to 130 mm per year. The average flock size is 642 ewes, but a quarter of the flocks consist of fewer than 300 ewes each and half the farmers have an income similar to that of schoolteachers. Farmers cannot afford to lose more animals – it is putting the local agricultural economy at risk.
‘They are trying to produce food and at the same time they are told to stop persecuting predators. We worked with farmers to understand exactly what is happening on these farms from an holistic perspective, including an assessment of predators, farm management and the general biodiversity status of the area,’ says behavioural ecologist Professor Justin O’Riain of the University of Cape Town’s Department of Biological Sciences.
One of the largest camera trap surveys
To gain a better understanding of how mesopredators like jackal and caracal behave, PhD student, Marine Drouilly, supervised by O’Riain, compared on-farm research data with research data from the Anysberg Nature Reserve, based on the largest camera trap surveys ever undertaken in the Karoo. Between October 2012 and June 2015, 332 camera traps were set up over the survey area of approximately 160 000 hectares.
Half of the camera traps were set up on the 22 sheep farms and the other half in the reserve. The camera trap findings were combined to produce a biodiversity assessment of the area. Smaller assessments have been done on individual farms but never on this scale.
80 farmers participated in the research
In addition, 80 farmers participated in the research and provided key information in questionnaires regarding their tolerance to wildlife and predators.
The WWF Nedbank Green Trust co-funded this project, which was managed by the University of Cape Town’s Sustainable Societies Unit in the Centre for Social Science Research (CSSR).
Several of the farmers claimed losses of up to 70% but it was not possible to confirm this as many of the farmers in the project research did not know exactly how many lambs they were supposed to have in a season. ‘Mainly for cost reasons, many of the farmers don’t scan their ewes so they do not know if they are pregnant or whether the ewe is carrying a single lamb or twins,’ Drouilly explains.
‘The four farmers who use electric fencing showed far lower sheep losses but many of the famers said all kinds of fencing was too expensive for them and that they did not have sufficient labour to regularly patrol their fences.’
Vegetation rehabilitation could be key
In this very arid environment, the grazing by sheep and goats limited and reduced the vegetation cover. The sparser the vegetation the lower the rodent population, with an accompanying increase in the predation of sheep by caracal and jackal. “What we found in this study is that predators prefer micromammals to domestic livestock, but domestic livestock are so much more abundant on farmlands and so they ended up as major prey for the mesopredators”, says Drouilly who used her camera trapping data as a measure of prey availability and an electivity index to determine which source of prey the predators were showing a preference for.
‘The data indicates that vegetation rehabilitation could be one of the keys to predator control, along with better protection of livestock,’ she adds.
Drouilly’s research also calls into question the adverse outcome of farmers’ longstanding approaches to controlling the predators, including poisoning. This is not only illegal it is completely counterproductive as it simultaneously kills the rodents that are an important part of the predators’ diet.
Comprehensive recent research by zoologist and conservation ecologist, Professor Graham Kerley, from Nelson Mandela Metropolitan University (NMMU) in the Eastern Cape, further revealed that farmers’ targeting of predators can lead to an increase in their numbers, as he explained: ‘The jackal females on farms breed younger and have more offspring at a younger age as a compensatory response to lethal management. The same response is not happening on nature reserves.’
Incorrect perception about weekend farms and nature reserves
There is also a strong perception amongst sheep and goat farmers that nature reserves and game farms provide refuges for jackals. Another important part of the project was to compare the diet of jackal and caracal using GPS clusters and scat to determine what they eat and where.
‘The analysis of scats showed the jackals in my study that moved between ‘weekend farms’ where there was no livestock and farms with livestock where they tended to prey mostly on sheep and also goats, as well as wild animals such rodents. The jackals in the Anysberg, by comparison, preyed predominantly on wild animals, mostly rodents, berries and insects, even when they roamed outside of the reserve.’
On-farm jackal diet
Drouilly explains that on the farms, the research showed that sheep and to a lesser extent goats comprised 42% of the diet of jackals living on sheep farms, compared to the existing literature, which averages at 20%. She also found that 10% of the diet of on-farm jackal comprised small rodents and 11% invertebrates, insects like crickets, grasshoppers and snakes. The remainder of the diet mainly comprised wild ungulates, birds and fruits.
On-farm caracal diet: 14% rodents
The diet of the caracal living on livestock farms comprised 25% livestock, 14% rodents, 12% insects and 12% small ungulates like duikers and springbuck. The rest of the diet comprised birds and other mammals such as hares and hyraxes.
Nature reserve diets of jackal and caracal
In the Anysberg reserve the diet for the jackal was completely different: 41% of their diet comprised of fruit, notably from the gwarrie tree, 36% from different types of micromammals and 8% insects.
The diet of the caracal in reserve comprised 58% micromammals, almost 13% insects and 5% small ungulates.
‘We GPS-collared 4 jackal on the farms and 4 in the Anysberg and even though they roamed onto farms for short periods we never found any signs of sheep or goat in either their kill sites or their scats,’ she says.
‘We were unable to GPS-collar any caracal in the Anysberg but on the farms we collared 12 – from sub-adult (2 years) to old ones (7 years).
‘What is interesting is that my preliminary on-farm analysis of GPS-collared caracals indicates that some of them never ate any sheep while others were eating almost one a week. Those that did not eat sheep preyed on a range of wild animals, including dassies, rabbits, hares, rock monitor lizards, aardwolf, steenbok, duiker and birds.’
Predator movement related to permanent water
‘We will also use the GPS collar data to establish where and when the jackal and caracal drink,’ continues Drouilly. ‘There is a strong sense that the movement of these predators into the Karoo over the past couple of decades could have a lot to do with the establishment of permanent water in the form of dams, boreholes and water troughs.’
Historically, many species including jackals would have moved in and out of these areas in accordance with the Karoo’s unpredictable rainfall. The provision of permanent water may thus have changed the ranging patterns of many species.
The fascinating case of Leroy
A fascinating case study in the project was a young male jackal they named Leroy. ‘He was captured and collared on a sheep farm 30 km from Beaufort West in May 2014. He was just two years at the time. He dispersed over 200 km to Laingsburg and the Floriskraal Dam area to establish his own territory. In total, he moved for 2000 km over 5 months through numerous farms and survived.’
What is special about this project is that academics and farmers are coming together over key livelihood and biodiversity issues.