Ecology and Interactions of Cape Foxes, Bat-eared Foxes, and Black-backed Jackals in South Africa
Project Animal(s) : Cape Foxes, Bat-eared Foxes, and Black-backed Jackals
Project Category : Mammals
Project Region : Africa
Project Type : Research
Project URL : https://www.wildcru.org/research/ecology-and-interactions-of-cape-foxes-bat-eared-foxes-and-black-backed-jackals-in-south-africa/
Project is timebound? : No
Between April 2005 and March 2008, led by Dr Jan Kamler, we studied the relationships among canid species in South Africa, primarily out of concern for declining cape fox numbers. Two sites were chosen: (1) Benfontein Game Farm, which had relatively high jackal numbers; and (2) private sheep farms adjacent to Benfontein, which had virtually no jackals. The overall goal was to compare densities, home ranges, activity, and other behaviors between sites for both fox species.
At total of 74 individual canids were captured and monitored on both sites, including 11 cape foxes, 22 bat-eared foxes, and 15 black-backed jackals on Benfontein, and 8 cape foxes and 18 bat-eared foxes in the sheep farms. Results showed that black-backed jackals had negative impacts on both cape foxes and bat-eared foxes. For example, predation from jackals was responsible for 71% of cape fox deaths, and 67% of bat-eared fox deaths. Black-backed jackals also appeared to negatively affect the home range and spatial distribution of cape foxes, as well as group sizes of bat-eared foxes. Cape foxes clearly avoided jackal core areas, thus cape foxes had to range over larger areas to safely find food in areas with high jackal densities. Additionally, cape foxes established natal dens only when > 2 km from jackal dens, thus there were few places on Benfontein where cape foxes could safely raise litters. This caused cape fox densities to decrease 64% on Benfontein compared to adjacent sheep farms. Ultimately, cape fox and jackal numbers were inversely related across several sites, so higher jackal numbers caused lower cape fox numbers, and cape foxes were completely excluded at the highest jackal densities.
Jackals did not appear to significantly influence movements or numbers of bat-eared foxes. However, group size of bat-eared foxes was 4-5 adults/group on Benfontein, but only 2-3 adults/group on the sheep farms. It appeared that in the presence of jackals, bat-eared foxes stayed in larger groups for better protection against predation. This has important implications concerning disease outbreaks, as the larger group sizes and more overlapping home ranges of bat-eared foxes on Benfontein probably increased their susceptibility to epizootics, which frequently occurred on Benfontein but not on the sheep farms.
Diets on Benfontein overlapped little between jackals and cape foxes (0.34), and jackals and bat-eared foxes (0.20), suggesting competition for food was minimal. The diet of jackals was dominated by ungulates, whereas cape foxes consumed primarily small rodents and insects, and bat-eared foxes consumed primarily termites and fruit. This suggests jackals were killing foxes not for competition over limited food resources, but rather for other reasons such as territorial space.
This research was funded by a Marie Curie Fellowship from the European Commission, Brussels, Belgium, and a Research Fellowship from the Wildlife Conservation Society, New York.
Project Agency : Wildlife Conservation Research Unit(WildCRU)
Project Agency Contact : https://www.wildcru.org/
Project Researcher : Dr Jan Kamler
Project Researcher Contact : [email protected]
Additional Information :
A short (14 min.) documentary of Jan’s research in South Africa: http://www.youtube.com/watch?v=5iRVGGkjC50