The cumulative curves plotted the number of scats against the number of all prey items found in the scats (Figure 4-6). For Kasanka NP, none of the curves exhibited the shape of an asymptote. The number of prey items was 19 for civets and white tailed mongooses while only 5 prey items were found in the scats of caracals. For Kafue Region, the number of prey items found in the scats was much less, only 5 prey items for each species.
Nevertheless, the curve of the hyena shows asymptotic features.
Figure 4-6: Cumulative curve showing the relation between the number of scats and the number of prey items found for all faecal samples found during this study.
In Kasanka NP, depending if considering FO or PO of prey (Table 4-3), crocodiles or civets had the highest amount of bovids in their diet. Servals, caracals and white-tailed mongooses rather consumed other mammals. Nevertheless, caracals and white-tailed mongooses preyed also on bovids while servals did not. All predators were found to feed on other prey items (e.g. birds, arthropods, fishes), but details on these results are not presented within this thesis. Concerning crocodile, the content of a high amount of faeces could not be determined. Beside the faeces from determined predators, faeces from unknown predators showed a high amount of bovid prey. One scat of spotted hyena was found; it included hair of bushbuck (Tragelaphus scriptus). Concerning bovid prey a number of 5 species was found in the scats in Kasanka NP (Table 4-4). Puku were consumed by crocodiles, white-tailed mongooses, and undetermined predators and to a considerable amount by civets. To about equal amounts puku and sitatunga (Tragelaphus spekii) were consumed by crocodiles. Also other predators consumed sitatunga. Bushbuck were eaten to
an extensive amount by almost all predators consuming bovids. Otherwise, reedbuck (Redunca arundinum) and bush duiker (Sylvicapra grimmia) were found as prey in the faeces.
In Kafue NP, on three occasions, faeces could not be related to a predator; probably they belong to a larger cat species. All three samples contained puku hair (Table 4-3). Both spotted hyenas and lion showed a high amount of bovid prey species concerning FO and PO.
While traces of only few other mammals were observed in the faeces of hyenas, lions consumed other mammals to about 30% in both FO and PO. In comparison to the analyses of the other scats, the amount of undetermined prey was rather high for the faecal samples of hyena. Both spotted hyenas and lions consumed puku to the highest amount of all bovids found (Table 4-4). For hyena the remaining amounts were shared rather equally by impala (Aepyceros melampus), bushbuck and waterbuck (Kobus ellipsiprymnus) with slightly higher amounts for the latter in FO and PO. Lions consumed reedbuck and, to a considerable amount, impala.
From all bovid species that were found in the faeces of predators in Kasanka NP, puku were consumed most (Figure 4-7). In terms of biomass it was eaten especially by civets, but also by crocodiles and to the least amount by white-tailed mongooses. Regarding bovid prey, only the mongoose fed above all on bushbuck, which is ranked second in the consumed biomass. Sitatunga ranked third was mainly eaten by crocodiles. The consumed biomass of bush duiker was the smallest amount. In Kafue Region, from all bovid species, the puku was by far consumed most in terms of biomass (Figure 4-8). Based on the relative amount of consumed biomass, the lion consumed more puku than hyena. In contrast to amounts based on FO and PO, the waterbuck made up a considerable part in the diet of hyena; it was the second prey behind the puku. Impala were not much consumed by any of two predators but rather by lions.
The analysis of preference via the JACOBS index resulted in values close to zero. Neither puku nor impala had high values of being avoided or preferred as prey by spotted hyenas (JACOBS index for puku: -0.004; JACOBS index for impala: 0.04) or lions (JACOBS index for puku: - 0.005;JACOBS index for impala: 0.013). Other bovid species found in the diets of predators, waterbuck, bushbuck and reedbuck, have a proportional abundance of less than 5% and were thus excluded from the analysis.
Table 4-3: Prey categories found in the faeces of predators in the study regions, expressed as frequency of occurrence (FO) (based on all scats of each predator) and percentage of occurrence (PO) (based on all determined prey items of each predator).
study region predator species faeces prey items bovid other mammals other prey items undefinite content Nile crocodile
(Crocodylus niloticus) 25 23 64.00/73.91 8.00/8.70 16.00/17.39 28 serval
(Leptailurus serval) 18 42 0/0 83.33/69.05 66.67/30.95 0
caracal
(Caracal caracal) 5 8 40.00/12.50 80.00/87.50 20.00/12.50 0 white-tailed mongoose
(Ichneumia albicauda) 25 48 32.00/14.58 72.00/54.17 52.00/31.25 4 African civet
(Civettictis civetta) 27 54 92.59/44.44 25.93/14.81 81.48/40.47 0 spotted hyena
(Crocuta crocuta) 1 1 100.00/100.00 0 0 0
undetermined predator 7 8 85.71/75.00 14.29/12.50 14.29/12.50 0 spotted hyena
(Crocuta crocuta) 70 64 82.86/95.31 4.29/4.69 0/0 17.14
lion
(Panthera leo) 22 24 77.27/70.83 31.82/29.17 0/0 4.55
undetermined predator 3 3 100.00/100.00 0/0 0/0 0
Kafue Region
number of FO/PO
Kasanka NP
Ecology and population status of the puku antelope (Kobus vardonii) in Zambia
Chapter 4: Predation on puku
predator) and percentage of occurrence (PO) (based on all prey items of each predator).
puku impala waterbuck sitatunga bushbuck reedbuck bush duiker
(Kobus vardonii) (Aepyceros melampus) (Kobus ellipsiprymnus) (Tragelaphus spekii) (Tragelaphus scriptus) (Redunca arundinum) (Sylvicapra grimmia) Nile crocodile
(Crocodylus niloticus) serval
(Leptailurus serval) caracal
(Caracal caracal) white-tailed mongoose (Ichneumia albicauda) African civet (Civettictis civetta) spotted hyena (Crocuta crocuta)
undetermined predator 14.29/12.50 0/0 0/0 14.29/12.50 42.86/37.50 14.29/12.50 0/0
spotted hyena (Crocuta crocuta) lion
(Panthera leo)
undetermined predator 100.00/100.00 0/0 0/0 0/0 0/0 0/0 0/0
0/0 0/0
54.55/50.00 18.18/16.67 0/0 0/0 0/0 4.55/4.17 0/0
Kafue Region
54.29/59.38 10.00/10.94 12.86/14.06 0/0 10.00/10.94
11.11/5.56
0/0 0/0 0/0 0/0 100.00/100.00 0/0 0/0
44.44/22.22 0/0 0/0 7.41/3.70 25.93/12.96 0/0
0
4.00/2.08 0/0 0/0 4.00/2.08 16.00/8.33 0/0 4.00/2.08
0/0 0/0 0/0 0/0 20.00/12.50 0
8.00/8.70
0/0 0/0 0/0 0/0 0/0 0/0 0/0
FO/PO of bovid prey study region predator species
Kasanka NP
24.00/26.09 0/0 0/0 28.00/30.43 8.00/8.70 0/
Figure 4-7: Biomass of different prey species consumed by predators in Kasanka NP; expressed as the cumulative percentage amount of the calculated consumed biomass of bovids in the diet of the predators. Nile crocodile (Crocodylus niloticus): N=25; white-tailed mongoose (Ichneumia albicauda): N=25; African civet (Civettictis civetta): N=27.
Figure 4-8: Biomass of different prey species consumed by predators in Kafue Region; expressed as the cumulative percentage amount of the calculated consumed biomass in the diet of the predators. Spotted hyena (Crocuta crocuta): N=70; lion (Panthera leo): N=22.