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To develop guidelines for the collection of independent field samples of scats for the quantification of wild dog (Lycaon pictus) diet we determined the passage rates of different wild dog prey items from feeding trials on a captive pack held at Marakele National Park, Limpopo Province. The minimum time to first detection was 5.5 hours after feeding (S.E. ± 1.52, n = 5) and prey items remained in the gut for an average of 79.4 hours (S.E. ± 6.00, n = 3). Differential passage rates of prey species were not pronounced. Observed passage rates were used to devise a sampling protocol for scats collected during a field study where scats were separated by a minimum period of 120 hours to ensure independence of samples. Comparison of the percentage occurrence of prey species in field-collected scats with the percentage occurrence from direct observations of kills illustrated the tendency for small prey to be underrepresented in the latter. However, the strong correlation between percentage occurrences in diet as determined by the two methods (rs = 0.85, P < 0.01, 13 d.f.) suggests that both methods can reliably determine the relative importance of prey in the diets of obligate carnivores such as wild dogs. The determination of maximum passage rates and subsequent guidelines for collection of independent faecal samples in the field could be a valuable tool for reducing inherent biases in carnivore diet studies.
Camera-trap surveys, when combined with capture-recapture models, are an accurate and cost-effective method for estimating the abundance of individually identifiable carnivore species such as leopards, Panthera pardus. Reliable population estimates for leopards are particularly useful as they enable informed conservation and management decisions for a species that, although widespread, is heavily persecuted. Here we present the results of a camera-trap survey that estimated the population density of leopards in Zululand Rhino Reserve (ZRR) in northern KwaZulu-Natal, South Africa. We divided our study area in half and subsampled each section for 40 days using 34 paired camera-trap stations. The combined data yielded captures of six individual leopards (3 male, 3 female) photographed on 19 occasions. Using the program CAPTURE, population abundance was estimated according to two models; one that assumes homogeneous capture probabilities among individual leopards (Mo) and one that allows for heterogeneity in capture probabilities between individuals (Mh). For model Mo, the resultant capture probability was 0.317 and estimated abundance was 6 ± 0.390 (6–6, 95% Cl). For model Mh, the resultant capture probability was 0.112 and estimated abundance was 17 ± 6.37 (10–37, 95% Cl). The area effectively sampled by the camera-traps was 234 km2. Therefore, the estimated population density of leopards in the reserve was 2.5 ± 0.195 leopards per 100 km2 according to model Mo, and 7.00 ± 2.64 leopards per 100 km2 according to model Mh. When compared with the results of similar surveys conducted in nearby reserves, our findings suggest that the leopard population in the ZRR is below carrying capacity. To encourage population recovery, we recommend that no trophy hunting of leopards be conducted in the reserve, that measures be introduced to reduce retaliatory killing of leopards by livestock owners in surrounding areas, and that the illegal trade in leopard skins be addressed.
The recent increase in habitat fragmentation across our continents calls for concern with regard to the future survival of wildlife. In this respect corridors and stepping-stones are important. Targeting a wide-ranging top-trophic carnivore, the aim of this study was to estimate the density and abundance of leopards (Panthera pardus) in an area that might serve as a stepping-stone between other larger protected areas. We deliberately used a survey method designed to balance resource utilization and relevance of the results to fit the purpose of a pilot survey. The Sangare Ranch Conservancy is a newly established, privately owned park in Kenya. Using non-invasive techniques we identified 13 individual leopards composing of approximately 80% males. In addition, we found 28 leopard signs per 100 km walked, a predicted carrying capacity of around nine leopards/100 km2 and a leopard predation pressure on neighboring goat stock of 5.6%. We suggest that the conservancy plays an important role for leopard ecology and comprises a geographical and ecological stepping-stone between other protected wild habitats in the region. The study also suggests more efficient methods for future non-invasive studies.
Global Positioning System (GPS) telemetry provides data to study spatial utilization patterns of animals. Spatial uncertainty due to poor accuracy and fix rates, however, may detract from inferences based on such data. The exclusion of two-dimensional (2D) locations may improve such inferences, but the prevalence of 2D locations may be a factor of landscape properties. In trials conducted using GPS units stationed at known positions, fix rate decreased significantly with increased canopy cover, but was unaffected by slope. Most (75%) of the locations recorded in closed woodland were 2D locations, suggesting that the exclusion of 2D locations may reduce estimates of the utilization of such habitats. Excluding 2D locations from records obtained for GPS units deployed on free-ranging elephants (Loxodonta africana) increased daily displacement distances, and changed the number of locations per habitat. However, selection ratios and estimates of home range area were not influenced by filtering location data. We concluded that although the exclusion of 2D locations improved the accuracy of locations per se, it resulted in significant data loss. This loss could alter inferences on patterns of spatial utilization.
The management objectives of Robben Island, a World Heritage Site, include the maintenance of the island's ecosystem. Yet little is known about the size and impacts of the island's population of introduced European rabbits (Oryctolagus cuniculus). We present the first quantitative assessment of the Robben Island rabbit population. Population estimates should be treated cautiously because of methodological biases, but were useful for identifying trends. Rabbit numbers fluctuated seasonally but were relatively stable between October 2003 and November 2005. Following a programme in 2006 to eradicate feral domestic cats (Felis catus), there was an apparent increase in the rabbit population and the highest estimate of rabbits was made in November 2008. By February 2009, rabbit numbers had decreased considerably and this was probably due to reduced food availability following the 2008 population explosion. Nevertheless, during 2009 rabbit numbers remained higher than they had ever been before November 2008. Rabbits usually preferred open-range habitat, but switched to transitional habitat when numbers were high. Single-species eradication programmes could have devastating impacts on the island's ecosystem. It is thus recommended that a thorough risk assessment be carried out and a holistic management strategy, rather than a single-species approach, be formulated.
To understand the abundance, distribution, and population trends of the common hippopotamus (Hippopotamus amphibius) in the Gonarezhou National Park (GNP), Zimbabwe, we (i) carried out an aerial survey along sections of major perennial rivers, namely Runde, Save and Mwenezi and other inland water pans, and (ii) analysed the long-term aerial survey data (1965–2008). For the aerial survey, a Piper PA-18 Super Cub aircraft was flown once along each of the three major rivers and associated pans in November 2008. We recorded a total of 187 hippos and 19 groups in the GNP. All sightings were in Runde River, Tambohata Pan and Massasanya Dam (density = 2.4 hippos/km). We found three trends in hippo populations in the GNP for the period 1965–2008. First, the period 1965–1982 was characterized by a significant increase in the hippo population (simple linear regression: loge[hippo population estimate] = 0.05[year] - 89.01; F1,13 = 56.26, P < 0.001, R2 = 0.81; average annual exponential rate of increase [r] = 0.05, 95% confidence interval [CI] for r = 0.03–0.06); second, the period 1983–1997 was characterized by a significant hippo population decline (simple linear regression: loge[hippo population estimate] = 355.87–0.18[year]; F1,10 = 10.44, P < 0.001, R2 = 0.51; r = -0.18, 95% CI for r = -0.30 to -0.05) and thirdly, r between two survey counts in 1997 and 2008 was 0.06. We attributed the overall decline in hippo abundance, the disappearance of the hippos in the Mwenezi River, and their huge decline in the Save River in the GNP primarily to past droughts, siltation and persecution in adjacent communal areas. We recommend collaborative efforts by the relevant authorities to ensure a continuous flow of water in the Mwenezi River. This will allow for the maintenance of hippo habitats downstream of the Manyuchi Dam, thus creating conducive environment for the re-establishment of the hippos in the Mwenezi River section in GNP. We also recommend that GNP's management should continue to monitor the hippo population and distribution in the park's major rivers and natural pans.
We determined the effect of region and gender on the physical (pH45min, temperature45min, pH24h, temperature24h, L*-value, a*-value, b*-value, hue-angle, chroma, drip loss, cooking loss and Warner-Bratzler shear force value) and sensory properties (aroma, flavour, initial juiciness, sustained juiciness, first bite and residue) of M. longissimus dorsi from blesbok (Damaliscus dorcas phillipsi). Meat from a total of 65 blesbok (males and females) from four regions (Maria Moroka, Gariep, Qua-Qua and Rustfontein in the Free State Province, South Africa) were evaluated. No gender effects were found in any of the physical characteristics. However, region influenced (P < 0.05) pH45min (mean: 6.17), pH24h (mean: 5.49), temperature24h (mean: 7.39°C), a*-values (mean: 12.90), chroma (mean: 15.73) and cooking loss (mean: 34.63%). Both region and gender had a significant effect on first bite and residue, whereas sustained juiciness was only influenced (P < 0.05) by region. Blesbok presented a meat that would be accepted by the consumer as indicated by values at the upper part of the sensory scale.
Studies of population genetics and genomics, morphometrics, endocrinology and immunology of primates often require effective methods of trapping and sedation. In this paper, we describe a progressively refined trap design used by the authors to trap more than 770 vervet monkeys (Chlorocebus aethiops) in southern and eastern Africa between 1973 and 2009. The design offers ease of construction, portability, sensitivity of the trigger mechanism and the ability to restrain animals for sedation. In addition to a detailed description of the trap design, this paper presents notes on strategies for baiting, temporal trends during trapping and possible application to other taxa
The historical and prehistorical occurrences of the Nile crocodile (Crocodylus niloticus) in the Eastern Cape and Western Cape provinces, South Africa, are poorly known. This can lead to confusion in the conservation policy and management of protected areas because it is uncertain where it might be appropriate to reintroduce or conserve the species. The problem is confounded because the recorded information is summarized in two sources that are hard to access. This information is examined and discussed. It shows that, historically, living crocodiles were seen or killed on the coast as far south as 32°18′S; 28°50′E, in the Dwesa State Forest, Eastern Cape, in the late 19th and early 20th centuries. However, there are museum specimens of skulls and teeth collected from localities farther south, between the mouths of the Keiskamma and the Keurbooms Rivers. These are probably of widely different ages, but older than the historical era beginning in the 16th century. There is no information on their geological or archaeological provenance. This suggests that the species' range limits expanded and contracted at least once through approximately 2°of latitude before the historical period. The former government of Transkei reintroduced the species to the Dwesa-Cwebe Nature Reserve in c. 1980. There is no evidence to suggest that it would be appropriate to reintroduce crocodiles south or westward of this population.
A study was undertaken between 1 January 2006 and 16 February 2007 to identify haemoparasites and gastrointestinal parasites infecting African wild dogs (Lycaon pictus) in KwaZulu-Natal (KZN) province, South Africa. Blood and faecal samples were opportunistically collected from wild dogs immobilized for collaring or translocation purposes (n = 24). Three common domestic canine gastrointestinal parasites, Toxocara canis, Dipylidium caninum and Ancylostoma spp., and two genera of canid protozoan GI parasites, Sarcocystis and Isospora, were identified in 12 fresh faecal samples. The seroprevalence of Ehrlichia canis from 24 individual serum samples analysed was 83%. However, only 21% of the 14 whole-blood smears evaluated for the presence of E. canis morulae within monocytes were positive. Twelve whole-blood smears were evaluated for the presence of Babesia canis trophozoites within erythrocytes and revealed 0% prevalence. Although there is currently no evidence of direct parasite-related mortality in the KZN population, the presence of internal parasites may be more detrimental to the overall health status of African wild dogs with immunosuppression as a result of other disease conditions, translocation stress, or inbreeding depression.
An out-of-range sighting of a spotted-necked otter, Lutra maculicollis, was recorded on the lower Orange River at Senderling's drift (28°7′S; 16°53′E), in the Ais/Ais Richtersveld Transfrontier Park. Notes are provided on its observed behaviour, which corresponds with that of its known biology. This record is 1200 km downstream from the known distribution. Mammal species inventories need to be more meticulously undertaken so as not to overlook any species, and particularly larger mammals.
A live Indo-Pacific humpback dolphin (Sousa chinensis) with two bite wounds resulting from a great white shark (Carcharodon carcharias) encounter was observed from the commercial whale-watching vessel, Whale Whisperer, in Gansbaai on 23 and 24 August 2006. The most severe wound was to the dolphin's left flank area, the other to the anterior portion of its dorsal ‘hump’. This is the first documented interaction and potential predatory shark attack on any cetacean species in Gansbaai, and is evidence that large great white sharks may opportunistically hunt humpback dolphins in this region of South Africa.
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