86 research outputs found
Colophospermum mopane Wood Utilisation in the Northeast of the Limpopo Province, South Africa
The use of Colophospermum mopane wood was quantified from six villages in the northeast of the Limpopo Province, South Africa. One hundred and eighty individuals were interviewed from the selected villages. Three villages were located in the depleted woodlands and the remaining three at abundant woodlands. Traditional governance structures within the selected villages and relevant conservation department officials were also interviewed. Colophospermum mopane is an essential source of fuelwood and provide poles used for construction of traditional structures. Each family uses 6.8 ± 0.1 kg of Colophospermum mopane fuelwood for cooking day-1 in the woodland depleted villages, while 8.2 ± 0.2 kg is used at the woodland abundant villages. Colophospermum mopane is preferred for construction of traditional structures because its wood is durable and is able to resists the effects of termites and wood borers
Local forage fish abundance influences foraging effort and offspring condition in an endangered marine predator
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.All data will be archived in the Dryad Digital Repository and BirdLife Seabird Tracking
Database.1. Understanding the functional relationship between marine predators and their prey is vital
to inform ecosystem-based management. However, collecting concurrent data on predator
behaviour and their prey at relevant scales is challenging. Moreover, opportunities to study
these relationships in the absence of industrial fishing are extremely rare.
2. We took advantage of an experimental fisheries closure to study how local prey abundance
influences foraging success and chick condition of Endangered African penguins Spheniscus
demersus in the Benguela Ecosystem.
3. We tracked 75 chick-provisioning penguins with GPS-time-depth devices, measured body
condition of 569 chicks, quantified the diet of 83 breeding penguins and conducted 12 forage
fish hydro-acoustic surveys within a 20 km radius of Robben Island, South Africa, over three
years (2011–2013). Commercial fishing for the penguins’ main prey, sardine Sardinops sagax
and anchovy Engraulis encrasicolus, was prohibited within this 20 km radius during the study
period.
4. Local forage fish abundance explained 60% of the variation in time spent diving for 14
penguins at sea within 2 days of a hydro-acoustic survey. Penguin foraging effort (time spent
diving, number of wiggles per trip, number of foraging dives and the maximum distance
travelled) increased and offspring body condition decreased as forage fish abundance
declined. In addition, quantile regression revealed that variation in foraging effort increased as
prey abundance around the colony declined.
5. Policy implications. Our results demonstrate that local forage fish abundance influences
seabird foraging and offspring fitness. They also highlight the potential for offspring condition
and the mean-variance relationship in foraging behaviour to act as leading indicators of poor
prey abundance. By rapidly indicating periods where forage resources are scarce, these
metrics could help limit seabird-fisheries competition and aid the implementation of dynamic
ocean managemen
Haulout site selection by southern elephant seals at Marion Island
Using data from an ongoing mark-resight programme at Marion Island, we tested empirically whether southern elephant seals prefer certain terrestrial sites to others during the breeding, moulting and winter haulouts, and whether the pattern of site use is the same for different age and sex groups. Southern elephant seals preferred some sites, while discriminating against other sites, with different age and sex classes using different sites for certain haulout events. Wintering young animals did not show strong site selection. Some popular sites were used for all haulouts by all age and sex groups, and apparently have all the requirements of a good site for terrestrial haulout by southern elephant seals. Site selection becomes more apparent with age, suggesting the role of haulout experience in site selection
The status and conservation of Cape Gannets Morus capensis
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordThe Cape Gannet Morus capensis is one of several seabird species that are endemic to the
Benguela upwelling ecosystem (BUS), whose populations recently decreased leading to
unfavourable Red List classifications. Application of JARA, a Bayesian state-space tool for IUCN
Red List assessment, to updated information on areas occupied by and nest densities of breeding
Cape Gannets at their six colonies suggested the species should be classified as Vulnerable.
However, the rate of decrease of Cape Gannets in their most recent generation exceeded that of
the previous generation, primarily as a result of large decreases at Bird Island, Lambert’s Bay,
and Malgas Island off South Africa’s west coast. Since the 1960s, there has been an ongoing
redistribution of the species from northwest to southeast so that c. 70% of the species now occurs
at Bird Island, Algoa Bay, on the eastern border of the BUS. Recruitment rather than adult survival
may be limiting the present population, although information on demographic parameters and
mortality in fisheries is lacking for colonies in the northern BUS. Major present threats to the
species include a substantially decreased availability of their preferred prey in the west, heavy
mortality of eggs, chicks and fledglings at and around colonies inflicted by Cape Fur Seals
Arctocephalus pusillus and other seabirds, substantial disturbance at colonies caused by Cape
Fur Seals attacking adults ashore, oiling and disease
Impact of medical plurality on care engagement and treatment outcomes among people living with HIV in Limpopo, South Africa
POPULATIONS OF SURFACE-NESTING SEABIRDS AT MARION ISLAND, 1994/95–2002/03
During the 1990s and early 2000s, populations of surface-nesting seabirds at Marion Island showed different trends, but for the majority of species numbers decreased. Reduced numbers of gentoo penguins Pygoscelis papua, eastern rockhopper penguins Eudyptes chrysocome filholi, Crozet shags Phalacrocorax [atriceps] melanogenis and probably macaroni penguins E. chrysolophus are most plausibly attributed to an altered availability of food. Decreases in numbers of dark-mantled sooty albatrosses Phoebetria fusca, light-mantled sooty albatrosses P. palpebrata, southern giant petrels Macronectes giganteus and possibly northern giant petrels M. halli may have resulted from mortality of birds in longline fisheries. However, populations of wandering Diomedea exulans and grey-headed Thalassarche chrysostoma albatrosses fluctuated around a stable level. Numbers of Subantarctic skuas Catharacta antarctica and kelp gulls Larus dominicanus breeding at Marion Island also decreased. Kerguelen Sterna virgata and Antarctic S. vittata terns remain scarce at the island. Trends for king penguins Aptenodytes patagonicus were not reliably gauged, but numbers probably remained stable or increased. There were large fluctuations in numbers of king penguin chicks surviving to the end of winter.Afr. J. mar. Sci. 25: 427–44
Prior infection with SARS-CoV-2 boosts and broadens Ad26.COV2.S immunogenicity in a variant-dependent manner
The Johnson and Johnson Ad26.COV2.S single-dose vaccine represents an attractive option for coronavirus disease 2019 (COVID-19) vaccination in countries with limited resources. We examined the effect of prior infection with different SARS-CoV-2 variants on Ad26.COV2.S immunogenicity. We compared participants who were SARS-CoV-2 naive with those either infected with the ancestral D614G virus or infected in the second wave when Beta predominated. Prior infection significantly boosts spike-binding antibodies, antibody-dependent cellular cytotoxicity, and neutralizing antibodies against D614G, Beta, and Delta; however, neutralization cross-reactivity varied by wave. Robust CD4 and CD8 T cell responses are induced after vaccination, regardless of prior infection. T cell recognition of variants is largely preserved, apart from some reduction in CD8 recognition of Delta. Thus, Ad26.COV2.S vaccination after infection could result in enhanced protection against COVID-19. The impact of the infecting variant on neutralization breadth after vaccination has implications for the design of second-generation vaccines based on variants of concern
Adaptation of Colophospermum mopane to extra-seasonal drought conditions: site-vegetation relations in dry-deciduous forests of Zambezi region (Namibia)
Cross-reactive neutralizing antibody responses elicited by SARS-CoV-2 501Y.V2 (B.1.351)
No abstract available.The South African Medical Research Council, the Centers for Disease Control and Prevention, the ELMA South Africa Foundation, the Wellcome Trust, the Fogarty International Center of the National Institutes of Health, the FLAIR Fellowship program, the European and Developing Countries Clinical Trials Partnership 2 of the European Union Horizon 2020 program, the South African Research Chairs Initiative of the Department of Science and Innovation and the National Research Foundation.http://www.nejm.orgam2022Internal Medicin
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