28 research outputs found
The influence of prey, pastoralism and poaching on the hierarchical use of habitat by an apex predator
As an apex predator, habitat selection by African lions, Panthera leo, is primarily determined
by bottom-up processes; however, increasing anthropogenic pressures may alter these
relationships. Using camera traps and track surveys in the Limpopo National Park,
Mozambique, we collected detection/non-detection data of lions and their prey and
combined these with occurrence data on bushmeat poaching activities and spatial data on
agro-pastoralist land use and other landscape features. We used hierarchical modelling
within an occupancy framework to determine the relative influences of ecological variables
on resource use and non-use by lions at two spatial scales. Habitat use by lions was most
strongly influenced by the occurrence of their preferred prey across both spatial scales.
However, lions were strongly negatively predicted by bushmeat poaching at the finer spatial
scale and generally negatively predicted by agro-pastoralist activities at the coarser scale.
Restricting our analysis to the home-range scale would have greatly underestimated the
impact of bushmeat poaching on the ecology of lions. The results of our study illustrate the
trophic dependency of prey resources to lions and the importance of considering scale
when investigating species habitat use. Importantly, our study also demonstrates the
limiting influence of bushmeat poaching on the use of habitat by an apex predator.K.T.E. and L.A.
were supported by the May and Stanley Smith
Trust, The Wipplinger KL Bursary Found, Wilderness
Wildlife Trust and Canada National Student
Grants.http://www.sawma.co.zaam201
Trophic scaling and occupancy analysis reveals a lion population limited by top-down anthropogenic pressure in the Limpopo National Park, Mozambique
The African lion (Panthera Leo) has suffered drastic population and range declines over the last few decades and is listed by
the IUCN as vulnerable to extinction. Conservation management requires reliable population estimates, however these data
are lacking for many of the continent’s remaining populations. It is possible to estimate lion abundance using a trophic
scaling approach. However, such inferences assume that a predator population is subject only to bottom-up regulation, and
are thus likely to produce biased estimates in systems experiencing top-down anthropogenic pressures. Here we provide
baseline data on the status of lions in a developing National Park in Mozambique that is impacted by humans and livestock.
We compare a direct density estimate with an estimate derived from trophic scaling. We then use replicated detection/nondetection
surveys to estimate the proportion of area occupied by lions, and hierarchical ranking of covariates to provide
inferences on the relative contribution of prey resources and anthropogenic factors influencing lion occurrence. The direct
density estimate was less than 1/3 of the estimate derived from prey resources (0.99 lions/100 km2 vs. 3.05 lions/100 km2).
The proportion of area occupied by lions was Y= 0.439 (SE = 0.121), or approximately 44% of a 2 400 km2 sample of
potential habitat. Although lions were strongly predicted by a greater probability of encountering prey resources, the
greatest contributing factor to lion occurrence was a strong negative association with settlements. Finally, our empirical
abundance estimate is approximately 1/3 of a published abundance estimate derived from opinion surveys. Altogether, our
results describe a lion population held below resource-based carrying capacity by anthropogenic factors and highlight the
limitations of trophic scaling and opinion surveys for estimating predator populations exposed to anthropogenic pressures.
Our study provides the first empirical quantification of a population that future change can be measured against.KTE and LA were supported by the May and Stanley Smith Trust, The Wipplinger KL Bursary Found, Wilderness Wildlife Trust and Canada National
Student Grants.http://www.plosone.orgam201
Use of site occupancy models for targeted monitoring of the cheetah
The cheetah Acinonyx jubatus has suffered dramatic range contractions and population
declines as a result of habitat degradation, prey depletion and conflict with
humans. Of further concern is that many of Africa’s remaining cheetah populations
persist in human-dominated and highly fragmented landscapes, where their
ecology is poorly understood and population data are lacking. Presence–absence
surveys may be a practical means to collect these data; however, failing to account
for detection error can lead to biased estimates and misleading inferences; potentially
having deleterious consequences for species conservation. The goal of this
study was to identify how an occupancy modelling technique that explicitly
accounts for detectability could be used for quantifying cheetah status in humanimpacted
landscapes. Replicated camera-trap and track surveys of 100-km2 sample
units were used to estimate the proportion of area occupied by cheetahs and to
determine the survey effort required to inform conservation planning. Based on our
results, 16 km [±standard error (SE) = 12–22] of walking or 193 camera-trap nights
(±SE = 141–292) are required to confirm cheetah absence at a given 100-km2 grid
cell (with 95% certainty). Accounting for detection resulted in an overall cheetah
occurrence estimate of 0.40 (SE = 0.13), which is 16% higher than the traditional
presence–absence estimate that ignores detection error. We test a priori hypotheses
to investigate factors limiting cheetahs using an occurrence probability model of
their preferred prey. The results show that both cheetahs and their prey were
strongly negatively influenced by human settlements. Our study provides an unbiased
estimate of occurrence that can be used to compare status across different sites
and as a basis for long-term monitoring. Based on our results, we suggest that track
and/or camera-trap surveys coupled with site occupancy models may be useful for
targeted monitoring of cheetahs across their distribution.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-7998hb201
Evidence for a resident population of cheetah in the Parque Nacional do Limpopo, Mozambique
Transboundary protected areas may be important for the conservation of large African carnivores because these species require large tracts of habitat to maintain viable population numbers and gene flow. Cheetah (Acinonyx jubatus Schreber, 1775), is a species that may benefit from transboundary conservation agreements. It occurs at naturally low population densities, makes use of large home ranges, and disperses over long distances, thus requiring large tracts of suitable habitat to maintain viable population numbers. Here we present the first scientific evidence of a breeding population of cheetah in Parque Nacional do Limpopo (PNL), Mozambique. We obtained data from camera-traps deployed during occupancy surveys conducted from 9 September 2011 to 31 August 2012 over a 3400 km2 study area located within the central third of PNL. These results highlight the importance of the Greater Limpopo Transfrontier Park (GLTFP) to the overall conservation of cheetah in Africa, and the potential value of transboundary protected areas for the conservation of wide-roaming terrestrial mammals.University of Pretoria, the Wilderness
Trust and CIB
Evidence for a resident population of cheetah in the Parque Nacional do Limpopo, Mozambique
Transboundary protected areas may be important
for the conservation of large African carnivores
because these species require large tracts of habitat
to maintain viable population numbers and gene
flow. Cheetah (Acinonyx jubatus Schreber, 1775), is
a species that may benefit from transboundary
conservation agreements. It occurs at naturally low
population densities,makes use of largehomeranges,
and disperses over long distances, thus requiring
large tracts of suitable habitat to maintain viable
population numbers. Here we present the first scientific
evidence of a breeding population of cheetah in
Parque Nacional do Limpopo (PNL), Mozambique.
We obtained data from camera-traps deployed
during occupancy surveys conducted from 9 September
2011 to 31 August 2012 over a 3400 km2 study
area located within the central third of PNL. These
results highlight the importance of the Greater
Limpopo Transfrontier Park (GLTFP) to the overall
conservation of cheetah in Africa, and the potential
value of transboundary protected areas for the
conservation of wide-roaming terrestrial mammals.The University of Pretoria and the Wilderness Trusthttp://www.sawma.co.za/am201
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Rhino poaching may cause atypical trophic cascades
Current anthropogenic pressures drive the widespread loss of apex consumers where the effects of their removal from a system may cascade through lower trophic levels, with unanticipated impacts (Estes et al. 2011; Ripple et al. 2014). Similarly, the observed global decline in large herbivores has complex outcomes for ecosystem functioning (Ripple et al. 2015). Key to predicting and understanding the consequences of declines in both these guilds has been the concept of ecological cascades. Thus, hypothesizing ecological pathways and species’ interactions is an important first step in forecasting ecological responses to changes in the abundance and distribution of both apex predators and large herbivores.
We raise the question of whether the recent surge in poaching of white rhinoceros (Ceratotherium simum) and, to a lesser extent, the less abundant black rhinoceros (Diceros bicornis) in the Kruger National Park, South Africa, is providing the ingredients for an atypical cascade – one in which the mechanisms include an artificial enhancement rather than reduction of apex predators. We further hypothesize that this atypical trophic cascade could act synergistically with another anthropogenic pressure, the related poaching of lions (Panthera leo) for body parts coveted by rhino poachers, and subsistence poaching of wild meat in the adjoining Limpopo National Park, Mozambique, leading to the creation of an “ecological trap” (where species mistakenly respond to environmental cues that no longer match habitat quality) for an endangered species.This is the publisher’s final pdf. The article is copyrighted by the Ecological Society of America and published by John Wiley & Sons, Inc. It can be found at: http://esajournals.onlinelibrary.wiley.com/hub/journal/10.1002/%28ISSN%291540-9309
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Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
The original version of this article unfortunately contained a mistake
Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
Site occupancy and habitat selection of cheetahs Acinonyx jubatus (Shreber, 1775) in a human-influenced landscape in Mozambique
The cheetah (Acinonyx jubatus) has suffered dramatic range contractions and population declines as a result of habitat degradation, prey depletion and conflict with humans. Of further concern is that many of Africa’s remaining cheetah populations persist in human-dominated and highly fragmented landscapes, where their ecology is poorly understood and population data are lacking. Presence-absence surveys may be a practical means to collect these data, however, failing to account for detection error can lead to biased estimates and misleading inferences; potentially having deleterious consequences for species conservation. The goal of this study was to identify how an occupancy modelling technique that explicitly accounts for detectability could be used for quantifying cheetah status in human-impacted landscapes. Replicated camera-trap and track surveys of 100 km2 sample units were used to estimate the proportion of area occupied by cheetah and to determine the survey effort required to inform conservation planning. Based on our results, 16 km (±SE = 12-22) of walking or 193 camera-trap nights (±SE = 141-292) are required to confirm cheetah absence at a given 100 km2 grid cell (with 95% certainty). Accounting for detection resulted in an overall cheetah occurrence estimate of 0.40 (±SE = 0.13), which is 16% higher than the traditional presence-absence estimate that ignores detection error. We test a priori hypotheses to investigate factors limiting cheetah using an occurrence probability model of their preferred prey. The results show that both cheetah and their prey were strongly negatively influenced by human settlements. Our study provides an unbiased estimate of occurrence that can be used to compare status across different sites and as a basis for longterm monitoring. Based on our results, we suggest that track and/or camera-trap surveys coupled with site occupancy models may be useful for targeted monitoring of cheetah across their distribution.Dissertation (MSc (Wildlife Management))--University of Pretoria, 2013.Animal and Wildlife SciencesMSc (Wildlife Management)Unrestricte