Browsing by Author "Jansen, Corle"

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    Determining the diet of an African mesocarnivore, the caracal: scat or GPS cluster analysis?
    (Nordic Council for Wildlife Research, 2019) Jansen, Corle; Leslie, Alison J.; Cristescu, Bogdan; Teichman, Kristine J.; Martins, Quinton
    The caracal Caracal caracal is the largest of Africa's small felids (<20 kg). Across much of Africa, particularly where larger predators have been extirpated, caracal are one of the main carnivores contributing to livestock predation. Caracal dietary studies are outdated, typically have small sample sizes and have mainly relied on scat analysis. We used a combination of scat analysis (n = 250 scats) and GPS cluster visitation (n = 458 clusters visited; n = 91 clusters with feeding events) to estimate caracal diet in South Africa's Succulent Karoo, a global biodiversity hotspot. Based on both methods, rock hyrax Procavia capensis was the caracal's main prey. Small mammals accounted for 25.3% of total biomass consumed by caracal using scat analysis, however, were absent based on GPS cluster investigations. Domestic sheep Ovis aries biomass consumed was much higher (59.5%) when inferred from GPS cluster visitation than from scats (5%). Wild medium-to-large mammalian prey had little variation between the two methods. GPS telemetry did not enable detection of small prey (<1 kg) and possibly over-represented large prey items, including livestock. Scat analysis provided a broader representation of caracal diet, but scat investigations could have underestimated larger prey since caracals ingest only small amounts of hair from large-bodied animals. We recommend a combination of GPS cluster visitation and scat analysis to determine the diet of caracal and other mesocarnivores across a range of prey sizes.
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    Diet of key predators responsible for livestock conflict in Namaqualand, South Africa
    (Stellenbosch : Stellenbosch University, 2016-03) Jansen, Corle; Leslie, Alison J.; Martins, Quinton; Stellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.
    ENGLISH ABSTRACT: Human-wildlife conflict (HWC) occurs in areas where humans and wildlife occupy the same area or compete for the same resources. Although some carnivores are responsible for incidental attacks on humans, predation on livestock is an increasingly common form of HWC. Understanding the ecology of these predators outside the confines of protected areas could provide insight into decreasing conflict and ensuring the persistence of these animals in non-protected areas. I analysed the diet of leopard (Panthera pardus), caracal (Caracal caracal) and black-backed jackal (Canis mesomelas) in Namaqualand, Northern Cape, South Africa, an area where HWC is commonly reported. Scats were collected for each predator in both protected areas (Namaqua National Park) and surrounding, non-protected farmlands (810 km²). Eight caracals were also collared to analyse caracal diet from GPS-cluster data. The diet of the three predators was assessed across both land classifications (protected vs. non-protected). Prey availability was determined by means of camera and small mammal traps and compared between the two land classifications. The relative abundance index (RAI) was used to determine the abundance of prey species on the two contrasting land classifications and whether prey abundance and availability influenced the feeding ecology of leopard, caracal and jackal in Namaqualand. All three predators relied on the most abundant and easy to catch prey species, reflecting opportunistic feeding behaviour. In the protected national park, where livestock was absent, all three predators selected for natural prey items. These findings coincided with previous studies on leopard, caracal and black-backed jackal in South Africa. A shift in leopard diet was observed on farmlands, as livestock replaced small-to medium-sized ungulates in scats. For black-backed jackals, steenbok (Raphicerus campestris) contributed >20% to the total biomass consumed in protected areas while on farmlands sheep (Ovis aries) contributed > 20% and steenbok only < 5%. These findings in scat are mirrored in ungulate surveys; steenbok was the most abundant small-to medium-sized ungulate in the national park and sheep were the most abundant prey on farmlands. Caracal preferred hyrax (Procavia capensis) and lagomorpha as prey, while predation on livestock occurred in low frequencies (scat analysis, 6.9%), making caracal the predator which depended the least on livestock. Land-use also had very little effect on caracal diet. When analysing caracal diet by means of kill site analysis, sheep contributed the bulk to the total biomass consumed (59.5%). However, GPS cluster analysis is inherently biased towards the overestimation of larger bodied prey items and excludes smaller prey items (< 1 kg) which contributed > 25% to the total biomass consumed according to scat analysis. Predation of livestock by these three predators was not significant in relation to livestock availability on farmlands, especially for caracal. Due to the opportunistic feeding behaviour of these predators it was more likely that livestock was an alternative prey source. A suitable natural prey base on farmlands would decrease livestock losses, especially where leopards depredate on stock. Leopards are the last remaining large predator in this area and the loss of these large felids could be detrimental to the healthy functioning of the ecosystem. If increased vigilance is practiced during the lambing period, lambs could survive to past their vulnerable size when they fall victim to jackals. Improved livestock husbandry methods, implementation of guarding animals and herders and various other holistic methods could decrease livestock losses in Namaqualand.