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