The diet of caracal (Caracal caracal) in the southern Free State

[摘要] Caracal is a damage-causing predator in rangeland ecosystems of southernAfrica, with the southern Free State being one of the most severely impacted small stockareas. Available literature indicate that these cats usually prey on the most abundant preygroups, but are also opportunistic and take small stock, especially during lambing seasons.The aim of this study was to define the diet of caracal over a 13 month period through scatanalysis in a small stock area and to discuss its prey-niche overlap and sharing with thethree most common sympatric carnivores-black backed jackal Canis mesomelas, Cape greymongoose Galerella pulverulenta and yellow mongoose Cynictis penicillata. The study sitewas described as a productive ecosystem and characterised by a diverse number of preyspecies. Prey availability was determined on a number of transects (driven and walked) andthrough numerous observations of birth peaks/the presence of young.Results show that caracal fed predominantly on Mammalia prey (94.74 percentageoccurrence, %Occ.; 93.40 percentage volume, %Vol.). Prey items that made the mostnotable contributions to caracal diet were Lagomorpha (28.5%Occ.; 28.0%Vol.), rock hyraxProcavia capensis (17.5%Occ.; 17.3%Vol.), and springhare Pedetes capensis (15.2%Occ.;15.2%Vol.) and domestic sheep Ovis aries (13.6%Occ.; 13.6%Vol.). Prey items that madethe most notable contributions to black-backed jackal diet were Muridae (34.43%Occ.;9.83%Vol.), Lagomorpha (19.94%Occ.; 16.98%Vol.), springbok Antidorcas marsupialis(13.92%Occ.; 12.92%Vol.), sheep Ovis aries (9.09%Occ.; 8.24%Vol.) and mountainreedbuck Redunca fulvorufula (9.82%Occ.; 9.42%Vol.).The current study showed that caracal was more of a specialist than black-backed jackal,with the latter utilizing the widest prey spectrum. Both caracal and black-backed jackal fedopportunistically in this study, and their diets included a large proportion of natural prey. Thediet of caracal and black-backed jackal included more mammal and less invertebrate preythan that of Cape grey mongoose and yellow mongoose.Of the four predators studied, black-backed jackal diet was the most diverse (widest nichebreadth), followed by Cape grey mongoose, caracal, and yellow mongoose diet the leastdiverse. The two larger carnivores, caracal and black-backed jackal, utilised their prey itemswith higher evenness than the two mongoose species. Highest niche overlap was observed between caracal and black-backed jackal (1.0), andbetween Cape grey mongoose and yellow mongoose (0.9). Moderate niche overlap wasobserved between caracal and Cape grey mongoose, and between black-backed jackal andCape grey mongoose (both 0.6; smallest overlaps were between caracal and yellowmongoose (0.3), and black-backed jackal and yellow mongoose (<0.1).Springhare remains in caracal scats correlated with monthly springhare abundance (r=0.8;p=0.004), which in turn correlated with humidity (r=-0.7; p=0.03). Hare Lepus spp. remainsin caracal scats did not correlate with hare monthly abundance (r=0.6; p=0.09), but followedthe same general trend. The results suggest that caracal fed on the most abundant preyand opportunistically exploited peaks in prey abundance.Both caracal and black-backed jackal preyed markedly on sheep during the two lambingseasons (March to April and September to October). Black-backed jackal predated less onthis prey item than caracal, but predated, more than caracal, on (also economicallyimportant) springbok. Both caracal and black-backed jackal were, therefore, damagecausingpredators in the study area, but also played an intricate role in the ecosystem in thatthey regulate prey populations and may benefit syntopic carnivores through, for example,carrion provision. Caracal and black-backed jackal may also serve as regulators of preyspecies that are also potential damage-causing animals (e.g. rodents destroying crops andcarrying disease, hyrax competing for forage with sheep, and molerat tunnels causingdamage to tractors and plows).Although the current research was a descriptive ecological study of caracal diet in arangeland ecosystem, and not a management focused project, it nevertheless providedinformation that can benefit farmers, conservation authorities and the government sector inthe quest to address the sensitive issues of predator control and ecosystem conservation onrangelands characterised by major small stock losses.

[发布机构] University of the Free State