25 research outputs found

    Factors affecting the impact of off-road driving on soils in an area in the Kruger National Park, South Africa

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    Studies on the effects of off-road driving on soils were conducted in the Makuleke Contractual Park of the Kruger National Park. The studies were conducted on three different soils with different textures and soil compactibilities. Traffic pressure was applied with a game drive vehicle loaded with 11 sand bags, each weighing 70 kg. This gave a total vehicle mass of 3,795 kg, simulating a vehicle fully laden with tourists. The study included: (i) comparing of the effects of four different tyre pressures; (ii) comparing the effects of 1–3 vehicle passes over the same tyre tracks; (iii) comparison of traffic effects under dry and wet soil moisture conditions, on soil compaction, respectively. After each pass penetration resistances were measured (a) on the tyre tracks, (b) between the tyre tracks and (c) at different distances outside the tyre tracks. As expected, vehicular traffic caused soil compaction below the wheel tracks. Lower tyre pressures caused less compaction than higher tyre pressures. Fewer vehicle passes also caused less compaction than more passes on the same tracks, but most compaction occurred during the first pass. Thus, driving on the same tracks more than once is less damaging than driving once on different tracks. Controlled traffic should be considered when developing management strategies for off-road driving in wildlife protected areas.http://link.springer.com/journal/267am201

    Three new species of ciliated protozoa from the hindgut of both white and black wild African rhinoceroses

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    This report deals with the effect of the mode of feeding of the hindgut-fermenting herbivorous rhinoceros on the species of Protozoa fermenting the ingesta, as demonstrated by the proposed three new species of ciliated Protozoa: Didesmis synciliata differing from D. ovalis in having syncilia in place of simple cilia, Blepharoconus dicerotos being twice the size of B. cervicalis, and Blepharosphaera ceratotherii being one third the size of B. intestinalis. The findings are in line with the biological tenet that in herbivores the composition of the diet is the major factor determining the composition of the digestive organisms.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Unusually high predation on chacma baboons (Papio ursinus) by female leopards (Panthera pardus) in the Waterberg Mountains, South Africa

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    Leopards do not preferentially favour baboons as prey, but they are considered the primary predators of baboons across Africa. Even in areas where baboons are abundant, their contribution to leopard diet seldom exceeds 5% of biomass. It is suggested that the extreme aggressiveness of baboons, group vigilance and their high mobility when escaping may limit leopard predation. Male baboons are particularly aggressive, and retaliation often leads to the death of the leopard. However, evidence suggests that leopards may learn to catch and kill certain dangerous prey. This study reports predation on chacma baboons by 3 female leopards on a private game reserve in the Waterberg Mountains of South Africa. Potential leopard feeding sites were identified using global positioning system (GPS) location clusters obtained from GPS collars. Over a 5-month period, we investigated 200 potential leopard feeding sites and located 96 leopard feeding/kill sites. Baboons constituted 18.7% of the leopards’ biomass intake. The majority of baboons preyed upon were adults and 70% of the kills were diurnal. In terms of the measured variables, there were no significant differences in the way the leopards preyed upon baboons, compared to the rest of the prey species.The Wilson Foundation and the Centre for Wildlife Management at the University of Pretoriahttp://www.paru.cas.cz/folia/am201

    The relative importance of trophy harvest and retaliatory killing of large carnivores : South African leopards as a case study

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    There are considerable challenges in the conservation of large carnivores, caused by large area requirements, low reproduction rates and low population densities coupled with their tendency to cause conflict with humans. Trophy hunting is one strategy to increase support for large carnivore conservation. Leopards,Panthera pardus, rank among the most soughtafter trophies in South Africa.However, trophy hunting has been suggested as partly responsible for leopard population declines, and leopards are also killed in retaliatory actions. In this study we used a stochastic population model to evaluate the relative influences of retaliatory killing and trophy harvest on leopard population persistence, and to assess the sustainability of the current leopard trophy harvest in South Africa. There was a stronger effect of variation in retaliatory killing than of harvest on population persistence. Although we found low extinction risks for South African leopards within 25 years, high risks of population declines across a wide range of simulation scenarios call for concern regarding the viability of the South African leopard population.We suggest that conflict mitigation may be more effective in promoting leopard persistence than restricting trophy harvest, and that accurate estimates of retaliatory killing are necessary for assessments of harvest sustainability.International Foundation for Science grant no. D/4984-1, Wild Foundation grant no. 2008-011, Wilson Foundation, University of Pretoria and the Endangered Wildlife Trust. L.H.S. was further supported by National Research Foundation of South Africa (NRF) grant no. 74819, F.D. was supported by a research fellowship from the University of Pretoria, M.S. by the DST-NRF Centre of Excellence for Invasion Biology and F.D. and M.S. were supported by the NRF.http://www.sawma.co.za/am201

    Quantifying the impact of off-road driving on root-area distribution in soils

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    Studies on the effects of off-road driving on soils were conducted in the Makuleke Contractual Park of the Kruger National Park. The studies were conducted on three different soils with different textures and soil compactibilities. Traffic pressure was applied with a game drive vehicle loaded with 10 sand bags, each weighing 70 kg, plus the driver. This gave a total vehicle mass of 3795 kg, simulating a vehicle fully laden with tourists. The results of the study reported here included comparing of the effects of four different tyre pressures on the root area distribution below each tyre pressure. At all sites, root density fractions under the tracks were reduced significantly at all tyre pressures, compared with the control values. Results indicated that root penetration percentage and root area distribution were reduced drastically as tyre pressure increased. Our work reaffirms previous research showing that higher tyre pressures cause higher sub-soil compaction than lower tyre pressures. Thus, driving with lower tyre pressures when driving off-road should be considered when developing management strategies for off-road driving in wildlife protected areas.http://www.sawma.co.zaam2016Centre for Wildlife ManagementPlant Production and Soil ScienceStatistic

    Examination of the rumen bacteria and methanogenic archaea of wild impalas (Aepyceros melampus melampus) from Pongola, South Africa

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    Although the rumen microbiome of domesticated ruminants has been evaluated, few studies have explored the rumen microbiome of wild ruminants, and no studies have identified the rumen microbiome in the impala (Aepyceros melampus melampus). In the present study, next-generation sequencing and real-time polymerase chain reaction were used to investigate the diversity and density of the bacteria and methanogenic archaea residing in the rumen of five adult male impalas, culled during the winter dry season in Pongola, South Africa. A total of 15,323 bacterial 16S rRNA gene sequences (from five impala), representing 3,892 different phylotypes, were assigned to 1,902 operational taxonomic units (OTUs). A total of 20,124 methanogen 16S rRNA gene sequence reads (from four impala), of which 5,028 were unique, were assigned to 344 OTUs. From the total sequence reads, Bacteroidetes, Proteobacteria, and Firmicutes were the most abundant bacterial phyla. While the majority of the bacterial genera found were unclassified, Prevotella and Cupriavidus were the most abundant classified genera. For methanogens, the genera Methanobrevibacter and Methanosphaera represented 94.3 % and 4.0 % of the classified sequences, respectively. Most notable was the identification of Methanobrevibacter thaueri-like 16S rRNA gene sequence reads in all four impala samples, representing greater than 30 % of each individual’s total sequences. Both data sets are accessible through NCBI’s Sequence Read Archive (SRA), under study accession number SRP [048619]. The densities of bacteria (1.26×1010–3.82×1010 cells/ml whole rumen contents) and methanogens (4.48×108–7.2×109 cells/ml of whole rumen contents) from five individual impala were similar to those typically observed in domesticated ruminants.http://link.springer.com/journal/2482016-04-30hb201

    The association between presenting complaints and clinical outcomes in emergency department patients of different age categories

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    BACKGROUND AND IMPORTANCE: Although aging societies in Western Europe use presenting complaints (PCs) in emergency departments (EDs) triage systems to determine the urgency and severity of the care demand, it is unclear whether their prognostic value is age-dependent. OBJECTIVE: To assess the frequency and association of PCs with hospitalization and mortality across age categories. METHODS: An observational multicenter study using all consecutive visits of three EDs in the Netherlands Emergency department Evaluation Database. Patients were stratified by age category (0-18; 19-50; 51-65; 66-80; >80 years), in which the association between PCs and case-mix adjusted hospitalization and mortality was studied using multivariable logistic regression analysis (adjusting for demographics, hospital, disease severity, comorbidity and other PCs). RESULTS: We included 172  104 ED-visits. The most frequent PCs were 'extremity problems' [range across age categories (13.5-40.8%)], 'feeling unwell' (9.5-23.4%), 'abdominal pain' (6.0-13.9%), 'dyspnea' (4.5-13.3%) and 'chest pain' (0.6-10.7%). For most PCs, the observed and the case-mix-adjusted odds for hospitalization and mortality increased the higher the age category. The most common PCs with the highest adjusted odds ratios (AORs, 95% CI) for hospitalization were 'diarrhea and vomiting' [2.30 (2.02-2.62)] and 'feeling unwell' [1.60 (1.48-1.73)]. Low hospitalization risk was found for 'chest pain' [0.58 (0.53-0.63)] and 'palpitations' [0.64 (0.58-0.71)]. CONCLUSIONS: Frequency of PCs in ED patients varies with age, but the same PCs occur in all age categories. For most PCs, (case-mix adjusted) hospitalization and mortality vary across age categories. 'Chest pain' and 'palpitations,' usually triaged 'very urgent', carry a low risk for hospitalization and mortality

    Citrulline supplementation improves organ perfusion and arginine availability under conditions with enhanced arginase activity

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    Enhanced arginase-induced arginine consumption is believed to play a key role in the pathogenesis of sickle cell disease-induced end organ failure. Enhancement of arginine availability with l-arginine supplementation exhibited less consistent results; however, l-citrulline, the precursor of l-arginine, may be a promising alternative. In this study, we determined the effects of l-citrulline compared to l-arginine supplementation on arginine-nitric oxide (NO) metabolism, arginine availability and microcirculation in a murine model with acutely-enhanced arginase activity. The effects were measured in six groups of mice (n = 8 each) injected intraperitoneally with sterile saline or arginase (1000 IE/mouse) with or without being separately injected with l-citrulline or l-arginine 1 h prior to assessment of the microcirculation with side stream dark-field (SDF)-imaging or in vivo NO-production with electron spin resonance (ESR) spectroscopy. Arginase injection caused a decrease in plasma and tissue arginine concentrations. l-arginine and l-citrulline supplementation both enhanced plasma and tissue arginine concentrations in arginase-injected mice. However, only the citrulline supplementation increased NO production and improved microcirculatory flow in arginase-injected mice. In conclusion, the present study provides for the first time in vivo experimental evidence that l-citrulline, and not l-arginine supplementation, improves the end organ microcirculation during conditions with acute arginase-induced arginine deficiency by increasing the NO concentration in tissues

    Survival rates and causes of mortality of leopards Panthera pardus in southern Africa

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    Estimation of survival rates is important for developing and evaluating conservation options for large carnivores. However, telemetry studies for large carnivores are often characterized by small sample sizes that limit meaningful conclusions. We used data from 10 published and 8 unpublished studies of leopards Panthera pardus in southern Africa to estimate survival rates and investigate causes of leopard mortality. Mean survival rates were significantly lower in non-protected (0.55 ± SE 0.08) compared to protected areas (0.88 ± 0.03). Inside protected areas juveniles had significantly lower survival (0.39 ± 0.10) compared to subadults (0.86 ± 0.07) and adults (0.88 ± 0.04). There was a greater difference in cause of death between protected and non-protected areas for females compared to males, with people being the dominant cause of mortality outside protected areas for both females and males. We suggest there is cause for concern regarding the sustainability of leopard populations in South Africa, as high female mortality may have severe demographic effects and a large proportion of suitable leopard habitat lies in non-protected areas. However, because a large proportion of deaths outside protected areas were attributed to deliberate killing by people, we suggest that management interventions may have the potential to increase leopard survival dramatically. We therefore stress the urgency to initiate actions, such as conflict mitigation programmes, to increase leopard survival in non-protected areas.The International Foundation of Science (D/4984-1), Wild Foundation (2008-011), Wilson Foundation and the University of Pretoria. LHS was further supported by the National Research Foundation (74819), FD by the National Research Foundation and a research fellowship from the University of Pretoria, and MJS by the Department of Science and Technology Centre of Excellence for Invasion Biology and the National Research Foundation.http://journals.cambridge.org/action/displayJournal?jid=ORXam201

    Angolan experience and how this can be done in the Congo (DRC), The

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    Presented at the 9th international wildlife ranching symposium: wildlife - the key to prosperity for rural communities, held on 12-16 September 2016 at Hotel Safari & the Safari Court, Windhoek, Namibia.The 27 year long civil war in Angola has devastated the national parks and wildlife populations of this country. In cooperation with the Angolan government we planned the return of many locally extinct species including elephant. All animals had to be airlifted, including elephant in family groups and giraffe plus 12 other species. The wildlife was all released into a Special Conservation Area within the Kissama national Park. The operation will be discussed, how it was planned, and the ecology behind it, the benefit to the local communities, and where it stands today. Wildlife in the Democratic Republic of the Congo has been devastated during the past years of civil war. The Kiala Community Land just north of the Angola border together with private land form a natural area of 500 000 ha. We are planning with the community to fence the first 75 000 ha and reintroduce wildlife in order to start a conservation plan based on ecotourism and the sustainable use of natural resources. Can we repeat the Angola project in DRC
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