27 research outputs found
Habitat structure and diversity influence the nesting success of an endangered large cavity-nesting bird, the Southern Ground-hornbill
Habitat features can have a profound effect on the nesting success of birds. Savannas are often
managed with predators and large herbivores as priority species, with little thought to the
many bird species that management decisions could affect. Using a data set spanning seven
breeding seasons, we examined how nesting success of Southern Ground-hornbills (SGHs)
Bucorvus leadbeateri in the Kruger National Park varied as a result of various environmental
and habitat factors within a radius of 3 km surrounding the nest site. Identifying which factors
affect nesting success will allow for targeted management efforts to ensure the long-term
survival of SGHs both within and outside of protected areas. Habitat structure and diversity
of the vegetation surrounding the nest were the most influential factors on SGH nesting
success. SGHs require open grassy areas for foraging and areas with large trees for nesting.
Savanna habitat drivers such as elephants and fire should be managed to ensure that sufficient
large trees are able to establish in the landscape and to control for bush encroachment. This is
especially important in areas earmarked for SGH reintroductions. Nest sites of SGHs should
be monitored to mitigate any structural changes in the habitat surrounding the nests. Nests
should be modified or artificial nest sites provided, where nests have been damaged or lost, to
ensure the continued presence of these birds in African savannas.
CONSERVATION IMPLICATIONS : Habitat structure and diversity surrounding Southern Groundhornbill
nests has a significant impact on their nesting success. This highlights the importance
of monitoring vegetation change in savanna habitats where they occur. Management of
savanna areas should take factors that influence bush encroachment, such as fire and elephants,
into account to ensure the long-term persistence of these birds.The Ford Wildlife Foundation and the First Rand
Foundation.http://www.koedoe.co.zaam2018Veterinary Tropical Disease
Presumed killers? Vultures, stakeholders, misperceptions, and fake news
Vultures and condors are among the most threatened avian species in the world due to the impacts of human activities. Negative perceptions can contribute to these threats as some vulture species have been historically blamed for killing livestock. This perception of conflict has increased in recent years, associated with a viral spread of partial and biased information through social media and despite limited empirical support for these assertions. Here, we highlight that magnifying infrequent events of livestock being injured by vultures through publically shared videos or biased news items negatively impact efforts to conserve threatened populations of avian scavengers. We encourage environmental agencies, researchers, and practitioners to evaluate the reliability, frequency, and context of reports of vulture predation, weighing those results against the diverse and valuable contributions of vultures to environmental health and human well-being. We also encourage the development of awareness campaigns and improved livestock management practices, including commonly available nonlethal deterrence strategies, if needed. These actions are urgently required to allow the development of a more effective conservation strategy for vultures worldwide.Peer reviewe
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African savanna raptors show evidence of widespread population collapse and a growing dependence on protected areas
The conversion of natural habitats to farmland is a major cause of biodiversity loss and poses the greatest extinction risk to birds worldwide. Tropical raptors are of particular concern, being relatively slow-breeding apex predators and scavengers, whose disappearance can trigger extensive cascading effects. Many of Africa’s raptors are at considerable risk from habitat conversion, prey-base depletion and persecution, driven principally by human population expansion. Here we describe multiregional trends among 42 African raptor species, 88% of which have declined over a ca. 20–40-yr period, with 69% exceeding the International Union for Conservation of Nature criteria classifying species at risk of extinction. Large raptors had experienced significantly steeper declines than smaller species, and this disparity was more pronounced on unprotected land. Declines were greater in West Africa than elsewhere, and more than twice as severe outside of protected areas (PAs) than within. Worryingly, species suffering the steepest declines had become significantly more dependent on PAs, demonstrating the importance of expanding conservation areas to cover 30% of land by 2030—a key target agreed at the UN Convention on Biological Diversity COP15. Our findings also highlight the significance of a recent African-led proposal to strengthen PA management—initiatives considered fundamental to safeguarding global biodiversity, ecosystem functioning and climate resilience
Tracking data highlight the importance of human-induced mortality for large migratory birds at a flyway scale
Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation
Risk factors for Coronavirus disease 2019 (Covid-19) death in a population cohort study from the Western Cape province, South Africa
Risk factors for coronavirus disease 2019 (COVID-19) death in sub-Saharan Africa and the effects of human immunodeficiency virus (HIV) and tuberculosis on COVID-19 outcomes are unknown. We conducted a population cohort study using linked data from adults attending public-sector health facilities in the
Western Cape, South Africa. We used Cox proportional hazards models, adjusted for age, sex, location, and comorbidities, to examine the associations between HIV, tuberculosis, and COVID-19 death from 1 March to 9 June 2020 among (1) public-sector “active patients” (≥1 visit in the 3 years before March 2020); (2) laboratory-diagnosed COVID-19 cases; and (3) hospitalized COVID-19
cases. We calculated the standardized mortality ratio (SMR) for COVID-19, comparing adults living with and without HIV using
modeled population estimates.Among 3 460 932 patients (16% living with HIV), 22 308 were diagnosed with COVID-19, of whom 625 died. COVID19 death was associated with male sex, increasing age, diabetes, hypertension, and chronic kidney disease. HIV was associated with
COVID-19 mortality (adjusted hazard ratio [aHR], 2.14; 95% confidence interval [CI], 1.70–2.70), with similar risks across strata of
viral loads and immunosuppression. Current and previous diagnoses of tuberculosis were associated with COVID-19 death (aHR,
2.70 [95% CI, 1.81–4.04] and 1.51 [95% CI, 1.18–1.93], respectively). The SMR for COVID-19 death associated with HIV was 2.39
(95% CI, 1.96–2.86); population attributable fraction 8.5% (95% CI, 6.1–11.1)
The first animals : ca. 760-million-year-old sponge-like fossils from Namibia
One of the most profound events in biospheric evolution was the emergence of animals, which is thought to have occurred some 600–650 Ma. Here we report on the discovery of
phosphatised body fossils that we interpret as ancient sponge-like fossils and term them Otavia antiqua gen. et sp. nov. The fossils are found in Namibia in rocks that range in age between about 760 Ma and 550 Ma. This age places the advent of animals some 100 to 150 million years earlier than proposed, and prior to the extreme climatic changes and postulated stepwise increases in oxygen levels of Ediacaran time. These findings support the predictions based on genetic sequencing and inferences drawn from biomarkers that the first animals were sponges. Further, the deposition and burial of Otavia as sedimentary particles may have driven the large positive C-isotopic excursions and increases in oxygen levels that have been inferred for Neoproterozoic time
West Nile Virus—Associated Encephalitis in Recipients of Renal and Pancreas Transplants: Case Series and Literature Review
Although West Nile fever is mild in the vast majority of infected persons, there is growing evidence that the disease may be more severe in the immunocompromised population. We describe 3 recipients of kidney or pancreas transplants who developed West Nile fever, 2 of whom had meningoencephalitis. As is the norm when treating serious infections in transplant recipients, a reduction of immunosuppression was pursued for these patients. Despite the severe nature of the disease in 2 patients, all recovered from the disease. The time course of neurologic recovery in the 2 patients with meningoencephalitis is highlighted. We also review the literature on West Nile fever in organ transplant recipients. In areas where West Nile virus is endemic, one must have a high index of suspicion for the illness when dealing with fever in transplant recipients
West Nile Virus—Associated Encephalitis in Recipients of Renal and Pancreas Transplants: Case Series and Literature Review
Although West Nile fever is mild in the vast majority of infected persons, there is growing evidence that the disease may be more severe in the immunocompromised population. We describe 3 recipients of kidney or pancreas transplants who developed West Nile fever, 2 of whom had meningoencephalitis. As is the norm when treating serious infections in transplant recipients, a reduction of immunosuppression was pursued for these patients. Despite the severe nature of the disease in 2 patients, all recovered from the disease. The time course of neurologic recovery in the 2 patients with meningoencephalitis is highlighted. We also review the literature on West Nile fever in organ transplant recipients. In areas where West Nile virus is endemic, one must have a high index of suspicion for the illness when dealing with fever in transplant recipients