Forecasting invasions: resource use by mussels informs invasion patterns along the South African coast

Invasive species are often more able to rapidly and efficiently utilise resources than natives, and comparing per capita resource use at different resource densities among invaders and trophically analogous natives could allow for reliable predictions of invasiveness. In South Africa, invasion by the Mediterranean mussel Mytilus galloprovincialis has transformed wave-exposed shores, negatively affecting native mussel species. Currently, South Africa is experiencing a second mussel invasion with the recent detection of the South American Semimytilus algosus. We tested per capita uptake of an algal resource by invading M. galloprovincialis, S. algosus, and the native Aulacomya atra at different algal concentrations and temperatures, representing the west and south coasts of South Africa, to examine whether their per capita resource use could be a predictor of their spread and subsequent invasiveness. Regardless of temperature, M. galloprovincialis was the most efficient consumer, significantly reducing algal cells compared to the other species when the resource was presented in both low and high starting densities. Furthermore, these findings aligned with a greater biomass of M. galloprovincialis on the shore in comparison with the other species. Resource use by the new invader S. algosus was dependent on the density of resource and, although this species was efficient at low algal concentrations at cooler temperatures, this pattern broke down at higher algal densities. This was once more reflected in lower biomass in surveys of this species along the cool west coast. We therefore forecast that S. algosus will be become established along the south coast; however, we also predict that M. galloprovincialis will maintain dominance on these shores.

Análisis comparado de las relaciones políticas entre Colombia y Ecuador y Venezuela durante la guerra de los mil días (1899-1902) y la crisis diplomática (2006-2008)

Este trabajo, a través de un análisis comparado de dos periodos muy distantes en el tiempo, muestra algunas similitudes de carácter político y diplomático, donde están involucrados los mismos actores a partir de un conflicto interno en Colombia.

The economic impact of genetically modified cotton on South African smallholders: Yield, profit and health effects

Results of a large-scale survey of resource-poor smallholder cotton farmers in South Africa over three years conclusively show that adopters of Bt cotton have benefited in terms of higher yields, lower pesticide use, less labour for pesticide application and substantially higher gross margins per hectare. These benefits were clearly related to the technology, and not to preferential adoption by farmers who were already highly efficient. The smallest producers are shown to have benefited from adoption of the Bt variety as much as, if not more than, larger producers. Moreover, evidence from hospital records suggests a link between declining pesticide poisonings and adoption of the Bt variety.

Impact of land cover changes on the South African climate

The Joint UK Land Environmental Simulator (JULES) was run offline to investigate the sensitivity of land surface type changes over South Africa. Sensitivity tests were made in idealised experiments where the actual land surface cover is replaced by a single homogeneous surface type. The vegetation surface types on which some of the experiments were made are static. Experimental tests were evaluated against the control. The model results show among others that the change of the surface cover results in changes of other variables such as soil moisture, albedo, net radiation and etc. These changes are also visible in the spin up process. The model shows different surfaces spinning up at different cycles. Because JULES is the land surface model of Unified Model, the results could be more physically meaningful if it is coupled to the Unified Model.

The economic impact of genetically modified cotton on South African smallholders: Yield, profit and health effects

Results of a large-scale survey of resource-poor smallholder cotton farmers in South Africa over three years conclusively show that adopters of Bt cotton have benefited in terms of higher yields, lower pesticide use, less labour for pesticide application and substantially higher gross margins per hectare. These benefits were clearly related to the technology, and not to preferential adoption by farmers who were already highly efficient. The smallest producers are shown to have benefited from adoption of the Bt variety as much as, if not more than, larger producers. Moreover, evidence from hospital records suggests a link between declining pesticide poisonings and adoption of the Bt variety.

Pesticide productivity and transgenic cotton technology: The South African smallholder case

This paper empirically investigates how the productivity of pesticide differs in Bt versus non-Bt technology for South African cotton smallholders, and what the implications for pesticide use levels are in the two technologies. This is accomplished by applying a damage control framework to farm-level data from Makhathini flats, KwaZulu-Natal. Contrary to findings elsewhere, notably China, that farmers over-use pesticides and that transgenic technology benefits farmers by enabling large reductions in pesticide use, the econometric evidence here indicates that non-Bt smallholders in South Africa under-use pesticide. Thus, the main potential contribution of the new technology is to enable them to realise lost productivity resulting from under-use. By providing a natural substitute for pesticide, the Bt technology enables the smallholders to circumvent credit and labour constraints associated with pesticide application. Thus, the same technology that greatly reduces pesticide applications but only mildly affects yields, when used by large-scale farmers in China and elsewhere, benefits South-African smallholder farmers primarily via a yield-enhancing effect.

Evidence for inclusion of South African endemic Nylandtia in Muraltia (Polygalaceae)

Nylandtia (Polygalaceae) is a small South African genus of two or more species distributed mainly in the Cape region. Previous studies based on anatomical, morphological and molecular data have already revealed a close relationship between Nylandtia and Muraltia, a genus of 117 species that is nearly endemic to South Africa. New evidence from molecular studies of family Polygalaceae and genus Muraltia shows that Nylandtia is derived from genus Muraltia, and is nested in Muraltia subgenus Psiloclada. These results have prompted a morphological re-evaluation of the genera Nylandtia and Muraltia, supporting the conclusion that the two species of Nylandtia currently recognized, N. spinosa and N. scoparia, should be included in subgenus Psiloclada within the genus Muraltia. Only one nomenclatural change is necessary: Muraltia spinosa (L.) E Forest & J. C. Manning, comb. nov.

Post-partum depression and infant growth in a South African peri-urban settlement

Aim: To examine the association between maternal post-natal depression and infant growth. Background: Infant growth has recently been shown, in two studies from South Asia, to be adversely affected by maternal depression in the early post-partum period. It is uncertain whether a similar association obtains in developing countries outside Asia. Method: A sample of 147 mother–infant dyads was recruited from a peri-urban settlement outside Cape Town and seen at 2 and 18 months post partum. Results: No clear effect of post-partum depression on infant growth was found. Although maternal depression at 2 months was found to be associated with lower infant weight at 18 months, when birthweight was considered this effect disappeared. Conclusions: Possible explanations for the non-replication of the South Asian findings are considered.

The mother-infant relationship and infant attachment in a south African peri-urban settlement

A sample of 147 mother-infant dyads was recruited from a peri-urban settlement outside Cape Town and seen at 2- and 18-months postpartum. At 18 months, 61.9% of the infants were rated as securely attached (B); 4.1% as avoidant (A); 8.2% as resistant (C); and 25.8% disorganized (D). Postpartum depression at 2 months, and indices of poor parenting at both 2 and 18 months, were associated with insecure infant attachment. The critical 2-month predictor variables for insecure infant attachment were maternal intrusiveness and maternal remoteness, and early maternal depression. When concurrent maternal sensitivity was considered, the quality of the early mother-infant relationship remained important, but maternal depression was no longer predictive. Cross-cultural differences and consistencies in the development of attachment are discussed.

The factor structure of the Edinburgh postnatal depression scale in a South African peri-urban settlement

The factor structure of the Edinburgh Postnatal Depression scale (EPDS) and similar instruments have received little attention in the literature. The researchers set out to investigate the construct validity and reliability of the EPDS amongst impoverished South African women. The EPDS was translated into isiXhosa (using Brislin's back translation method) and administered by trained interviewers to 147 women in Khayelitsha, South Africa. Responses were subjected to maximum likelihood confirmatory factor analysis. A single factor structure was found, consistent with the theory on which the EPDS was based. Internal consistency was satisfactory (a = 0.89).

Perceptions of informal safety nets: a case study from a South African informal settlement

The relevance and importance of informal safety nets that buffer poor households from livelihood hardships have been given little attention in South Africa’s development programmes to date. This article contributes to the understanding of informal safety nets by investigating local perceptions in a South African informal settlement. The main findings of the study are that families perform an important safety net function, but that these sources of assistance can be susceptible to social isolation. Immediate neighbours and friends also play an important safety net role, but these reciprocal-based sources of assistance may be difficult to secure. Community-wide threats can have a severe impact on people’s ability to engage in safety net transfers. Many of these difficulties stem from South Africa’s structural unemployment crisis. This factor is the greatest danger to the future of the informal safety net system in the informal settlement.

Whistle-blowing by external auditors: seeking legitimacy for the South African audit profession?

Auditing is often cited as playing an important role in managing agency-related costs and, accordingly, being integral to the sound functioning of capital markets. There may, however, be more to the attest function than a technical rational practice. By virtue of relying heavily on claims to technical expertise, professionalism, prudential judgement and public confidence, auditing is both a source of legitimacy for organisations and, paradoxically, dependent on claims to legitimacy for its continued existence. From this perspective, recent regulatory developments, purportedly enacted to increase arms-length control over the profession, may not only be about improving perceived audit quality and practice but also about ensuring continued faith in the well-established ‘rituals’ of the assurance function. A reporting duty imposed on South African external auditors, akin to whistle-blowing, is used as a case study to explore this perspective. In doing so, this paper contributes to the scant body of interpretive research on auditing, simultaneously offering one of the first insights into auditing regulation from an African perspective.