26 Works

Strengthening Resilience Across Scales: Moving Cities beyond COVID-19

Andrea Lampis

The role of shade in maintaining alternative stable states between open- and closed-canopy vegetation

Simon Power, G. Anthony Verboom, William Bond, Kirsten Packer & Michael Cramer
Fire is commonly identified as strong driver of alternative stable states such as adjacent open- versus closed-canopy vegetation types. The absence of open-canopy species from closed-canopy understoreys, where light availability is low and dynamic, however, suggests shade tolerance is an integral determinant of such vegetation boundaries. While the importance of light dynamics between alternative stable states has been acknowledged, the physiological mechanisms behind sun versus shade-tolerance are unclear. Here we investigated the differences in light...

Survey of Jewish South Africans

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Irradiations at the High-Energy Neutron Facility at iThemba LABS

A. Buffler, G. Reitz, S. Röttger, F. D. Smit & F. Wissmann
Abstract: Secondary high-energy neutrons are produced when high-energy particles (of several GeV) interact with matter as it is the case for cosmic radiation impinging on the Earth’s atmosphere, during ion-beam therapy or on shielding at high-energy particle accelerators. Especially, after traversing a large amount of matter, the residual neutron energy spectrum exhibits two energy regions which mainly contribute to the total ambient dose equivalent: around 1 MeV (evaporation peak) and around 100 MeV. Particle detectors...

Range-wide population viability analyses reveal high sensitivity to wildflower harvesting in extreme environments

Martina Treurnicht, Frank Schurr, Jasper Slingsby, Karen Esler & Joern Pagel
The ecological effects of harvesting from wild populations are often uncertain, especially since the sensitivity of populations to harvesting can vary across species’ geographical ranges. In the Cape Floristic Region (CFR, South Africa) biodiversity hotspot, wildflower harvesting is widespread and economically important, providing an income to many rural communities. However, with very few species studied to date, and without considering range-wide sensitivity to harvesting, there is limited information available to ensure the sustainability of wildflower...

Choice of nest attributes as a frontline defense against brood parasitism

Angela Moreras
Breeding- and nest-site choice is a behavioral strategy often used to counter negative interactions. Site choices prior to breeding prevents costs of predation and competition but has been neglected in the context of brood parasitism. For hosts of brood parasites, the earlier brood parasitism is prevented in the breeding cycle the lower the future costs. Suitable nest-sites for cavity-nesting common redstarts (Phoenicurus phoenicurus), a host of the common cuckoo (Cuculus canorus), are a limited resource,...

The future of African nowcasting

Lorraine Youds, Douglas Parker, Elijah A Adefisan, Leonard Kofitse Amekudzi, Jeffrey N. A. Aryee, Ifeoluwa Adebowale BALOGUN, Alan Blyth, Bernard Chanzu, Sylvester Danuor, Abdoulahat Diop, Jennifer Fletcher, Andre K Foamouhoue, Amadou T Gaye, Morne Gijben, Steven Goodman, Peter Hill, Ishiyaku Ibrahim, David Koros, Kamoru Abiodun Lawal, John Marsham, Bethwel Mutai K, Joseph Mutemi, Coumba Niang, Ousmane Ndiaye & Eniola Olaniyan
Nowcasting (weather forecasting predictions from zero to several hours) has enormous value and potential in Africa, where populations and economic activity are highly vulnerable to rapidly changing weather conditions. Timely issuing of warnings, a few hours before an event, can enable the public and decision-makers to take action. Rainfall radar estimates are not widely available in Africa, nor likely to be in the coming years, and numerical weather prediction (NWP) currently has low skill over...

Targeting acetylcholine receptors to enhance immunity to infection

William Horsnell, Luke B. Roberts, Corinna Corinna Schnoeller, Matthew Darby, Claire Mackowiak, Delphine Sedda, Valerie Quesniaux, Bernhard Ryffel, Rachel Vaux, Rita Berkachy, Kleoniki Gounaris & Murray E. Selkirk

Data from: The impact of long-term azithromycin on antibiotic resistance in HIV-associated chronic lung disease

Regina Esinam Abotsi, Mark P. Nicol, Grace McHugh, Victoria Simms, Andrea M. Rehman, Charmaine Barthus, Lucky G. Ngwira, Brenda Kwambana-Adams, Robert S Heyderman, Jon Ø Odland, Rashida A Ferrand & Felix S. Dube
Background: Selection for resistance to azithromycin (AZM) and other antibiotics such as tetracyclines and lincosamides remains a concern with long-term AZM use for treatment of chronic lung diseases (CLD). We investigated the impact of 48 weeks of AZM on the carriage and antibiotic resistance of common respiratory bacteria among children with HIV-associated CLD. Methods: Nasopharyngeal (NP) swabs and sputa were collected at baseline, 48 and 72 weeks from participants with HIV-associated CLD randomised to receive...

Facilitation and competition shape a geographical mosaic of flower colour polymorphisms

Anina Coetzee, Colleen Seymour & Claire Spottiswoode
1. Flower colour differs dramatically between populations for some plant species, yet we know little about what drives this variation. Such polymorphisms can be influenced by plant-pollinator interactions, but whether they are also influenced by pollinator-mediated plant-plant interactions is unknown. 2. We test whether flower colour polymorphisms can arise through convergence (facilitation) or divergence (competition) of flower phenotypes resulting from plant-plant interactions mediated by the shared, and only, pollinator (orange-breasted sunbird) of ten Erica communities...

Cities of Integrity Survey 2020

Derailed commuting: A qualitative exploration of the travel burden on low-income women in Cape Town

Carlyn Morilly & Roger Behrens

SARS-CoV-2 encephalitis presenting as a clinical cerebellar syndrome: a case report

Katryn Oosthuizen, Elizabeth Christina Steyn, Lawrence Tucker, Innocent Vusimusi Nchube, Diana Hardie & Suzaan Marais
This report contributes to the rapidly expanding knowledgebase of COVID-19-associated neurological syndromes and highlights uncertainties regarding the pathogenesis of cerebellar dysfunction in, and optimal management of, patients with COVID-19-associated encephalitis.

Environmental heterogeneity explains contrasting plant species richness between the South African Cape and southwestern Australia

Ruan Van Mazijk, Michael D. Cramer & G. Anthony Verboom
Aim: To assess whether a difference in species richness per unit area between two mediterranean-type biodiversity hotspots is explained by differences in environmental heterogeneity. Location: The Greater Cape Floristic Region, South Africa (GCFR) and Southwest Australian Floristic Region (SWAFR). Taxon: Vascular plants (tracheophytes). Methods: Comparable, geospatially explicit environmental and species occurrence data were obtained for both regions and used to generate environmental heterogeneity and species richness raster layers. Heterogeneity in multiple environmental variables and species...

How hornbills handle heat: sex-specific thermoregulation in the southern yellow-billed hornbill

Andrew McKechnie, Barry Van Jaarsveld, Nigel Bennett, Zenon Czenze, Ryno Kemp, Tanja Van De Ven & Susan Cunningham
At a global scale, thermal physiology is correlated with climatic variables such as temperature and aridity. There is also evidence that thermoregulatory traits vary with fine-scale microclimate, but this has received less attention in endotherms. Here we test the hypothesis that avian thermoregulation varies with microclimate and behavioural constraints in a non-passerine bird. Male and female southern yellow-billed hornbills (Tockus leucomelas) experience markedly different microclimates while breeding, with the female sealing herself into a tree...

A new sectional classification of Lachenalia (Asparagaceae) based on a multilocus DNA phylogeny

Graham D. Duncan, Carl D. Schlichting, Felix Forest, Allan G. Ellis, Alan R. Lemmon, Emily Moriarty Lemmon & G. Anthony Verboom
Lachenalia J.Jacq. ex Murray (Asparagaceae; Scilloideae; Hyacintheae) is a large and morphologically diverse genus of more than 140 bulbous species endemic to southern Africa. Previous attempts to infer a well resolved and robustly supported phylogeny of Lachenalia using Sanger sequencing of candidate loci and/or morphological characters have been largely unsuccessful. Consequently, the current infrageneric classification is artificial and there is a need to explore alternative avenues to produce a phylogenetic classification. In this paper we...

Data from: Malar stripe size and prominence in peregrine falcons vary positively with solar radiation: Support for the solar glare hypothesis

Michelle Vrettos, Chevonne Reynolds & Arjun Amar
Many falcons (Falco spp.) exhibit a distinct dark plumage patch below the eye, termed the malar stripe. This stripe is hypothesised to reduce the amount of solar glare reflected into the eyes while foraging, thereby increasing hunting efficiency in bright conditions. Here, we use a novel, global-scale correlative approach to test this “solar glare hypothesis” in peregrine falcons (Falco peregrinus), the most widespread falcon species, using web-sourced photographs from across the species’ global range. We...

CPR dataset for: Testing Bergmann's Rule in Marine Copepods

Max D. Campbell, David S. Schoeman, William Venables, Rana Abu-Alhaija, Sonia D. Batten, Sanae Chiba, Frank Coman, Claire H. Davies, Martin Edwards, Ruth Eriksen, Jason D. Everett, Yutaka Fukai, Mitsuo Fukuchi, Octavio Esquivel Garrote, Graham Hosie, Jenny Huggett, David G. Johns, John A. Kitchener, Philippe Koubbi, Felicity R. McEnnulty, Erik Muxagata, Clare Ostle, Karen V. Robinson, Anita Slotwinski, Kerrie M. Swadling … & Anthony J. Richardson
This is the global dataset used for the Campbell et al. (2021) paper “Testing Bergmann’s Rule in marine copepods”. The dataset includes the mean length of copepods weighted by abundance found in 97,830 continuous plankton recorder (CPR) samples. Further, it contains satellite observations for sea surface temperature, chlorophyll-a, and dissolved oxygen (see paper for details). It was a massive collaborative effort to get this dataset assembled by the Global Alliance of CPR Surveys (GACS 2011,...

Information Contagion and Systemic Risk

Toni Ahnert & Co-Pierre Georg
We examine the effect of ex-post information contagion on the ex-ante level of systemic risk defined as the probability of joint bank default. Because of counterparty risk or common exposures, bad news about one bank reveals valuable information about another bank, triggering information contagion. When banks are subject to common exposures, information contagion induces small adjustments to bank portfolios and therefore increases overall systemic risk. When banks are subject to counterparty risk, by contrast, information...

South African Lockdown Smoking Survey 2020

Understanding arid‐region waterbird community dynamics during lake dry‐downs

Graeme Cumming & Dominic Henry
These data were collected to explore changes in the bird community associated with Lake Ngami, Botswana, through successive drydown periods. Our analysis shows significant shifts, driven partially by changes in water level, in the species composition of the bird community over the period of study. The data set contains standardised half-hour point counts for the bird community of Lake Ngami, Botswana; and R code used for community-level analyses of the resulting time series. Counts were...

Registration Year

  • 2021
    26

Resource Types

  • Dataset
    20
  • Text
    3
  • Data Paper
    1
  • Journal Article
    1
  • Output Management Plan
    1

Affiliations

  • University of Cape Town
    26
  • South African National Biodiversity Institute
    2
  • Stellenbosch University
    2
  • Nigerian Meteorological Agency
    1
  • iThemba Laboratory
    1
  • London School of Hygiene & Tropical Medicine
    1
  • University of Hohenheim
    1
  • Kwame Nkrumah University of Science and Technology
    1
  • Helmholtz Zentrum München
    1
  • University of Pretoria
    1