African ungulates recognize a locally extinct native predator

Large carnivores are important ecosystem components but frequently suffer local extinctions. However, reintroductions and shifting conservation attitudes have lead to some population repatriations. Since the ecological consequences of predation may relate to indirect effects of predation risk, reconstruction of carnivore ecosystem function could depend on adequate predator recognition by prey. We evaluated behavioral responses in naive and lion exposed impala (Aepyceros melampus), blue wildebeest (Connochaetes taurinus), and warthogs (Phacochoerus africanus) to audio calls of a native (African lion Panthera leo) and an alien (grey wolf Canis lupus) predator as well as to unfamiliar (music) and familiar (running water) neutral controls. Our results demonstrated stronger behavioral responses to lions than to any of the other calls, even in naive populations, and suggest that retained predator recognition may enable rapid reconstruction of carnivore ecosystem function throughout Africa. However, since recognition may be lost in large increments, we urge that carnivore repatriations should be a prioritized component of African ecosystem conservation.National Geographic/Wait’s Foundation (grant number W32-08), the National Research Foundation (grant number NRF66135), and by the University of Pretoria.http://beheco.oxfordjournals.org2016-01-30hb201

Spotted hyaena space use in relation to human infrastructure inside a protected area

Increasing human population growth has led to elevated levels of human-carnivore conflict. However, some carnivore populations have adapted to urban environments and the resources they supply. Such associations may influence carnivore ecology, behaviour and life-history. Pockets of urbanisation sometimes occur within protected areas, so that anthropogenic influences on carnivore biology are not necessarily confined to unprotected areas. In this study we evaluated associations between human infrastructure and related activity and space use of spotted hyaenas within one of the largest protected areas in South Africa, the Kruger National Park. Home range size was smaller for the dominant female of a clan living in close proximity to humans than that of the dominant female of a clan without direct access to human infrastructure. The home range including human infrastructure was also used less evenly during the night, presumably when the animals were active. Within this home range, a village area was preferred during the night, when the least modified areas within the village were preferred and administration and highly modified areas were avoided. During the day, however, there were no preference or avoidance of the village area, but all habitats except unmodified habitats within the village area were avoided.Wesuggest that human infrastructure and associated activity influenced hyaena space use, primarily through alterations in the spatial distribution of food. However, these effects may have been indirectly caused by habitat modification that generated favourable hunting habitat rather than a direct effect caused by access to human food such as garbage. Because of the often pivotal effects of apex predators in terrestrial ecosystems, we encourage further work aimed to quantify how human presence influences large carnivores and associated ecosystem processes within protected areas.Supplement 1. Estimation of convergence of home range size estimates. To evaluate whether or not we had sufficient sample sizes to estimate seasonal home ranges we created accumulation curves for each clan and season. We created randomized sets of coordinates with increasing sample sizes from 10 relocations up to the actual sample size used for each seasonal range. For each sample size, we randomly drew 100 data sets without replacements from the original sets of coordinates that was utilized to calculate each seasonal home range, and for each random data set we calculated the area covered by a 100% MCP. These areas were plotted against sample size. (10.7717/peerj.2596/supp-1)Supplement 2. Raw data on animal locations. (DOI: 10.7717/peerj.2596/supp-2)This study was funded through incentive funding for rated researchers by the National Research Foundation (E Cameron, F Dalerum), a research fellowship from University of Pretoria (F Dalerum) as well as a Ramón y Cajal fellowship by the Spanish Ministry of Comptitiveness and Economy (F Dalerum).https://peerj.comam2017Mammal Research InstituteZoology and Entomolog

Spotted hyaena space use in relation to human infrastructure inside a protected area

Increasing human population growth has led to elevated levels of human-carnivore conflict. However, some carnivore populations have adapted to urban environments and the resources they supply. Such associations may influence carnivore ecology, behaviour and life-history. Pockets of urbanisation sometimes occur within protected areas, so that anthropogenic influences on carnivore biology are not necessarily confined to unprotected areas. In this study we evaluated associations between human infrastructure and related activity and space use of spotted hyaenas within one of the largest protected areas in South Africa, the Kruger National Park. Home range size was smaller for the dominant female of a clan living in close proximity to humans than that of the dominant female of a clan without direct access to human infrastructure. The home range including human infrastructure was also used less evenly during the night, presumably when the animals were active. Within this home range, a village area was preferred during the night, when the least modified areas within the village were preferred and administration and highly modified areas were avoided. During the day, however, there were no preference or avoidance of the village area, but all habitats except unmodified habitats within the village area were avoided.Wesuggest that human infrastructure and associated activity influenced hyaena space use, primarily through alterations in the spatial distribution of food. However, these effects may have been indirectly caused by habitat modification that generated favourable hunting habitat rather than a direct effect caused by access to human food such as garbage. Because of the often pivotal effects of apex predators in terrestrial ecosystems, we encourage further work aimed to quantify how human presence influences large carnivores and associated ecosystem processes within protected areas.Supplement 1. Estimation of convergence of home range size estimates. To evaluate whether or not we had sufficient sample sizes to estimate seasonal home ranges we created accumulation curves for each clan and season. We created randomized sets of coordinates with increasing sample sizes from 10 relocations up to the actual sample size used for each seasonal range. For each sample size, we randomly drew 100 data sets without replacements from the original sets of coordinates that was utilized to calculate each seasonal home range, and for each random data set we calculated the area covered by a 100% MCP. These areas were plotted against sample size. (10.7717/peerj.2596/supp-1)Supplement 2. Raw data on animal locations. (DOI: 10.7717/peerj.2596/supp-2)This study was funded through incentive funding for rated researchers by the National Research Foundation (E Cameron, F Dalerum), a research fellowship from University of Pretoria (F Dalerum) as well as a Ramón y Cajal fellowship by the Spanish Ministry of Comptitiveness and Economy (F Dalerum).https://peerj.comam2017Mammal Research InstituteZoology and Entomolog

Landscape Level Effects of Lion Presence (Panthera leo) on Two Contrasting Prey Species

Due to the strong individual cost of being predated, potential prey species alter their behavior and physiology in response to predation risk. Such alterations may cause major indirect consequences on prey populations that are additive to the direct demographic effects caused by prey being killed. However, although earlier studies showed strong general effects of the presence of apex predators, recent data suggest that indirect effects may be highly context dependent and not consistently present. We combined behavioral data with data on endocrine stress and stable isotopes to assess landscape level effects of lion (Panthera leo) presence on two prey species in South Africa, impala (Aepyceros melampus) and blue wildebeest (Connochaetes taurinus). We also evaluated if there was any seasonal variation in such effects. In addition, we provide results from a physiological validation for an enzyme-linked immunoassay (EIA) that can be used for non-invasive monitoring of glucocorticoid stress metabolite concentrations in impala from fecal pellets. We did not find any significant differences in vigilance behavior, fecal glucocorticoid metabolite concentrations, δ13C values or isotope niche breadth between animals living with and without lions for either species. However, wildebeest living in a reserve with lions spent more time foraging compared to wildebeest in a lion-free environment, but only during the wet season. Values of fecal δ15N suggest a shift in habitat use, with impala and wildebeest living with lions potentially feeding in less productive areas compared to animals living without lions. For both species, characteristics of the social groups appeared to be more important than individual characteristics for both foraging and vigilance behavior. Our results highlight that antipredator responses may be highly dynamic and scale-dependent. We urge for further studies that quantify at what temporal and spatial scales predation risk is causing indirect effects on prey populations

CENP-A and topoisomerase-II antagonistically affect chromosome length

The size of mitotic chromosomes is coordinated with cell size in a manner dependent on nuclear trafficking. In this study, we conducted an RNA interference screen of the Caenorhabditis elegans nucleome in a strain carrying an exceptionally long chromosome and identified the centromere-specific histone H3 variant CENP-A and the DNA decatenizing enzyme topoisomerase-II (topo-II) as candidate modulators of chromosome size. In the holocentric organism C. elegans , CENP-A is positioned periodically along the entire length of chromosomes, and in mitosis, these genomic regions come together linearly to form the base of kinetochores. We show that CENP-A protein levels decreased through development coinciding with chromosome-size scaling. Partial loss of CENP-A protein resulted in shorter mitotic chromosomes, consistent with a role in setting chromosome length. Conversely, topo-II levels were unchanged through early development, and partial topo-II depletion led to longer chromosomes. Topo-II localized to the perimeter of mitotic chromosomes, excluded from the centromere regions, and depletion of topo-II did not change CENP-A levels. We propose that self-assembly of centromeric chromatin into an extended linear array promotes elongation of the chromosome, whereas topo-II promotes chromosome-length shortening

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. Findings Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. Interpretation ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials

Anthropogenic influences on spotted hyaenas in a protected area the Kruger National Park

Human population growth generally causes carnivore declines. The rapid expansion of urban landscapes creates both biotic and abiotic changes that are known to negatively impact carnivore populations (Šálek, Drahníková & Tkadlec, 2015). Carnivores are considered particularly sensitive to human population growth and urbanisation due to persecution, large home range requirements and slow population growth (Woodroffe, 2000). This can cause local extinctions or active avoidance of humans by carnivores (Ordeñana et al., 2010; Schuette et al., 2013). However, some carnivore species are attracted to areas with high human population densities due to the benefits associated with the use of human based resources such as food and shelter. The spotted hyaena (Crocuta crocuta) is the most social of all hyaena species. Clans vary in size from three in the Kalahari up to 80 in East Africa. Spotted hyaenas typically eat prey of medium to large body size. The spotted hyaena is known for its opportunistic scavenging and the species will readily exploit anthropogenic food. In contrast to many species associated with anthropogenic food use, spotted hyaenas are large carnivores that often hunt larger prey. In this study I tested how life-history characteristics influenced visitation at known human resource sites, how the amount of anthropogenic material in scat samples varied in relation to human habitation, and how anthropogenic activity and infrastructure modified the behaviour of a large carnivore, the spotted hyena, in the Kruger National Park. I found that subadults and juveniles were the most frequent visitors at known anthropogenic sites, and I suggest that hyaenas were not visiting the anthropogenic sites in a need of food. Analysis of scats taken from the whole range of the southern section of the park showed that anthropogenic use was quite low, but also that the use was higher in the dry than in the wet season. However, anthropogenic material did not seem to have been included in hyaena diets in proportion to its availability. Instead, anthropogenic resources appear to have been utilised only by certain hyaenas or cohorts. Despite a presumed low value of anthropogenic resources, human activity and infrastructure were still altering spotted hyaena behaviour. A collared hyaena living in an area with large amounts of anthropogenic activity and infrastructure had a smaller home range that was used less evenly than another collared female living with less contact with humans. Home range size and use also exhibited seasonal variation, with larger areas used in the dry season. Spotted hyaenas inhabiting areas with higher human activity and infrastructure exhibited lower social network density and longer path lengths than those living away from human activity. However, my results did not fully follow those predicted by variations in resource abundance. We predicted that hyaena clans in areas with denser infrastructure and more human activity would show less group cohesiveness and hence both less dense and less complex social networks, caused by a greater access to anthropogenic food and therefore a decreased need for group related foraging.To conclude, my results suggests that anthropogenic resources in the Kruger National Park were of limited nutritional value for or not preferred by spotted hyaenas, but that they were still utilised and influenced spotted hyaena space use and social interactions. These observations are perplexing, and I suggest that further work is needed to improve our understanding of the impact of human activity and infrastructure inside protected areas on native wildlife populations.Thesis (PhD)--University of Pretoria, 2017.Zoology and EntomologyPhDUnrestricte

Anthropogenic influences on spotted hyaena diet in the Kruger National Park, South Africa

Rapid urban expansion has led to an increase in carnivores that live close to human dominated environments. Some carnivore species have successfully adapted to these novel conditions and taken advantage of opportunities associated with human habitation. Whilst many studies have compared carnivores living in protected areas to those in an urban setting, few have looked at the relationships between carnivores and human habitation within protected areas. In this study, we examined the effects of human habitation on the diet of spotted hyaenas (Crocuta crocuta) in the Kruger National Park (KNP), South Africa. Our results suggested a limited effect of anthropogenic resources on spotted hyaena diet in the KNP. We found neither temporal nor spatial variation in the amount of, nor types of, anthropogenic material in spotted hyaena scats, despite observations of more road side litter close to large anthropogenic sites. We therefore suggest that anthropogenic resources may not have been utilised completely according to abundance. We encourage further research evaluating potential secondary effects of human activity and infrastructure on spotted hyaena diet and also stable isotope approaches that may provide further insights into the importance of anthropogenic food for spotted hyaenas inside the KNP

Anthropogenic influences on spotted hyaena diet in the Kruger National Park, South Africa

Rapid urban expansion has led to an increase in carnivores that live close to human dominated environments. Some carnivore species have successfully adapted to these novel conditions and taken advantage of opportunities associated with human habitation. Whilst many studies have compared carnivores living in protected areas to those in an urban setting, few have looked at the relationships between carnivores and human habitation within protected areas. In this study, we examined the effects of human habitation on the diet of spotted hyaenas (Crocuta crocuta) in the Kruger National Park (KNP), South Africa. Our results suggested a limited effect of anthropogenic resources on spotted hyaena diet in the KNP. We found neither temporal nor spatial variation in the amount of, nor types of, anthropogenic material in spotted hyaena scats, despite observations of more road side litter close to large anthropogenic sites. We therefore suggest that anthropogenic resources may not have been utilised completely according to abundance. We encourage further research evaluating potential secondary effects of human activity and infrastructure on spotted hyaena diet and also stable isotope approaches that may provide further insights into the importance of anthropogenic food for spotted hyaenas inside the KNP.The National Research Foundation (incentive funding for rated researchers to EZC and FD), by the University of Pretoria and by the Spanish Ministry of Economy and Competitiveness (a research fellowship to FD).https://link.springer.com/journal/133642019-07-01hj2018Mammal Research InstituteZoology and Entomolog