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Formerly widespread throughout the waterbodies of eastern South Africa, viable Nile crocodile (Crocodylus niloticus) populations are now restricted to three disjunct protected areas in KwaZulu-Natal (KZN), Mpumalanga and Limpopo. Growing evidence suggests that protected populations are declining, including the breeding C. niloticus population at Lake Sibaya in KZN. Aerial surveys were conducted at Lake Sibaya from 2003–2004 and 2007–2009, spotlight counts in 2003 and intensive nesting surveys in 2003 and 2004. Seven adults were counted during the 2009 aerial survey; an 89% decrease from the 1985 count (62 adults) and a decline of 95–98% of the estimated 1970 adult population. Likewise, in 1970 30 nests were recorded, compared to three nests in 2003 and no recorded nests in 2004. The non-hatchling population in 2003 was estimated at 48 individuals and decreased to an estimated eight in 2009. The neighbouring community perceives crocodiles as a threat to their lives and livestock, and increasing human pressures on C. niloticus in the area will probably ensure that the population will not recover naturally. Unless crocodiles are perceived as a useful or somehow beneficial natural resource by the surrounding community, the species faces possible extirpation from Lake Sibaya in the future.
Bontebok National Park was established to protect the bontebok from extinction and more recently a small herd of Cape mountain zebra was also introduced into the park. Although the latter were introduced into the park to facilitate the grazing of bontebok and thereby reduce the use of fire by park management, recent work suggests that these ungulates compete for recently burnt veld. This work, however, was done at a relatively broad scale, while we used counts of bontebok and mountain zebra dung groups to assess the habitat use of these ungulates at a finer scale. In our analysis we stratified the study area according to vegetation type, veld age and fire history. Our results suggest that bontebok are more closely associated with burnt veld than mountain zebra and that both favour the Drainage Line and Kraal Lawn vegetation types over the other vegetation types in the park. The importance of these vegetation types has previously been overlooked and should be included in future monitoring of herbivore habitat use.
Past events of drought in different ecosystems in Kenya have been linked to mass deaths of elephants (Loxodonta africana). However, it is possible that other factors such as parasitism could be acting in synergy with drought and result in mortality. During the severe drought of 2009 in the Laikipia-Samburu ecosystem in Kenya, 38 young elephants (5–8 years old) died. Necropsy of 11 fresh elephant carcasses revealed pathological lesions on the intestinal mucosa and haemorrhages which were linked to parasitism. A nematode, Grammocephalus clathratus, from the bile duct, a trematode, Protofasciola robusta, from the duodenum and a complex of unidentified nematodes from the lower gut were isolated from the elephants. The carcasses were overly emaciated and the intestinal system was devoid of digesta. It is likely that starvation and dehydration could have triggered a vicious cycle of host malnourishment, a result of combined inadequate food and nutritional deprivation by intestinal parasites which lead to emaciation, pathology and death.
Feline immunodeficiency virus is a retrovirus of domestic cats that causes immunosuppressive disease and lifelong infection. Lentivirus has also been detected in African lions (Panthera leo). The lentivirus infecting lions in southern Africa has never been isolated; thus, knowledge about its molecular characteristics in these populations is limited. Our investigation used whole blood samples collected opportunistically from free-ranging southern African lions in Kruger National Park, South Africa, and from Hlane Royal National Park in Swaziland to analyse the lentivirus. Whole blood samples from captive exotic felids from zoos in South Africa and the United States, and from domestic cats in South Africa were analysed for comparison. A nested polymerase chain reaction (PCR) assay was used to amplify a portion of the proviral DNA encoding the reverse transcriptase. The nucleotide sequence of all products was determined and examined. The PCR assay was successful in amplifying lion lentivirus, with 52 positive and 65 negative samples. Of the 34 sequences amplified from a variety of felids, six showed an average of 96% homology to domestic feline lentivirus, and 28 showed an average of 94% homology to lion lentivirus. In addition, domestic cat lentivirus nucleic acid was amplified from a captive tiger, demonstrating the possibility of cross-species transmission.
We collected data on the demography of cheetahs by direct observation over nine years on Kwandwe Private Game Reserve and by questionnaire on seven fenced reserves in South Africa. Average age at independence was 17.5 months; females gave birth to their first litter of cubs at approximately 27.4 months and the average interbirth interval was 17.8 months. The average litter size at emergence was 4.2 and there was a significant difference between litter sizes at independence on reserves with lions (2.9 cubs) compared to those without (4.7 cubs). Age specific mortality was higher in the first four years of life (40–70%) than year five to nine (0%) and increased after year nine. Mortality of adult cheetahs was higher on reserves with lions compared to those without and there was a significant positive relationship (R2 = 0.56; P < 0.05) between cheetah mortality and the density of large predators on these reserves. We conclude that the reproductive rate of cheetahs that have been reintroduced to fenced reserves is high. Mortality of cubs and young adult cheetahs is elevated in the presence of lions and other carnivores. However, even under these conditions small reserves may serve as a source for cheetahs that can be used to re-stock other areas.
Small population sizes provide several challenges to conservation managers seeking to ensure species persistence and illustrating conservation success. Black rhinoceros, Diceros bicornis minor, epitomizes these challenges. During October 2008 we used block surveys, estimates of availability and observer bias to calculate landscape-specific black rhino abundances in the southern parts of Kruger National Park, South Africa. We assigned age and sex to individuals, extracted an age distribution, and estimated survival and fecundity given the population growth derived from historical strip transects. The block counts, corrected for 90.3% availability bias with observers missing 3.8% of those, predicted that 627 (95% CI: 588–666) black rhinos resided in the study area. The population increased at 6.75% per annum, the result of high survival and an estimated inter-calving interval of 2.45 years. Age distributions and population growth predicts that subadult males and females have the lowest annual survival, while dependent calves and adults have the highest annual survival. Precise estimates can be obtained with a 20% study area coverage using block counts. This gives coefficient of variances allowing detection of 5% growth from surveys every two years. Detecting 2% annual decline requires bi-annual surveys for 6 years. Our results illustrate that black rhinos are performing well in Kruger National Park.
Killer whales and leatherback turtles are infrequently sighted in the coastal waters of southern Africa. Year round observations in Walvis Bay, Namibia of killer whales (2003–2010) by multiple marine tour operators and opportunistic seasonal observations of leatherback turtles made during a cetacean research project in the area (2008–2010) have been collated. Visits to coastal waters by killer whales (n = 16) are sporadic and unpredictable but are slightly higher (n = 11) between late winter (August) and late summer (March). Leatherback turtles were only seen in the warmer periods of summer months (February–March) when the surface waters exceeded 15°C. Two interactions (one harassment and one probably predation) between killer whales and leatherback turtles have been recorded in Walvis Bay. This is the first report of killer whales eating leatherback turtles in the South Atlantic. These observations are noteworthy due to the low frequency of encounters of both species in the area, suggesting predation of turtles may be relatively common. Knowledge of the diet of killer whales is valuable due to the importance of dietary specialization in definition of ecotypes of the species.
The Muscularis longissimus dorsi of eight blue wildebeest (Connochaetus taurinus), collected at Sandveld Nature Reserve, South Africa, were analysed for biochemical and physical characteristics and chemical composition. The initial (6.60) and final (5.41) pH, drip loss (4.91%), cooking loss (39.42%) and maximum Warner-Bratzler shear force (4.91 kg/ 1.27 cmø) were comparable to values found in meat from several other African game species (black wildebeest, blesbok, duiker, impala, red hartebeest, reedbuck, springbok, warthog). Like other wild ungulates, blue wildebeest meat had a higher crude protein (22.28%) and lower lipid (1.06%) content compared to beef, which makes it a healthy alternative to traditional red meat.
A study was carried out between August 2007 and January 2008 to determine the prevalence of helminth parasites of cane rats (Thryonomys swinderianus) and grey duikers (Sylvicapra grimmia) cropped from Asejire Game Reserve in Osun State, southwestern Nigeria. Totals of 93 and 13 faecal samples, respectively collected from cane rats and grey duikers, were examined for helminth parasites using sodium chloride floatation and zinc sulphate sedimentation methods. Of the 93 and 13 faecal samples examined from cane rats and grey duikers 78 (83.3%) and 7 (53.8%), respectively, were positive for helminth ova. For cane rats, Strongyle ova 71 (76.3%) was the most frequently observed followed by Strongyloides 38 (40.8%) Trichuris 33 (35.4%), Cestode 9 (9.6%) and Ascaris 5 (7.5%). For antelopes Strongyle ova 6 (46.0%) was also the most frequently encountered followed by Trichuris 4 (31.0%), Ascaris 2 (15.0%) and Cestode 1 (8.0%). Strongyloides ova were not detected in the faecal samples examined for grey duikers. No trematode ova were detected in any of the samples examined. Larvae of Haemonchus and Trichostrongylus were common to both cane rats and grey duikers faecal cultures. Cane rats carried greater worm burdens than grey duikers. The number of eggs per gram of faeces for Strongyle was the highest 390.6 ± 154.9 and 420.0 ± 1.0 for cane rats and grey duikers, respectively. We recommend health education for all the people concerned in handling the animals, including the consumers of bushmeat in whatever form.
Goose barnacles (Lepas australis) were found attached to satellite-tracking and time-depth recording (TDR) instruments carried by two lactating Subantarctic fur seals (Arctocephalus tropicalis) from Marion Island. We report on the movements of these seals, both of which crossed the Subantarctic Front. Barnacles surrounding the temperature probe of one TDR device did not appear to directly influence temperature recordings, although disturbances to recording accuracies by other high-precision devices carrying goose barnacles are considered likely.
An opportunistic observational study on human disturbance of a vagrant southern elephant seal that was hauled out on a tourist beach in Mossel Bay, South Africa, is presented. Incidences of pedestrians ignoring signage and the demarcation barrier around the seal raise questions about the management of such haulout events, pubic safety and the effects of disturbance.
The release of tortoises after confinement and treatment in rehabilitation centres includes the risk that released individuals may infect wild conspecifics with foreign parasites and other pathogens. The recent monitoring of the release of rehabilitated leopard tortoises (Stigmochelys pardalis) onto private land in KwaZulu-Natal province, South Africa, revealed that the health-checking protocol at the wildlife rehabilitation centre was inadequate. As a result the provincial conservation authority placed a moratorium on further leopard tortoise releases until a comprehensive health-checking protocol was in place. This protocol is detailed here to ensure the success of the release of confiscated and rehabilitated leopard tortoises, and that this does not come at cost to the wild leopard tortoise populations.
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