Sublethal agrochemical residues in South African birds, 1969–2024

Aim Apparent anthropogenic warming has been underway in South Africa for several decades, a period over which significant range shifts have been observed in some indigenous bird species. We asked whether these range shifts by birds are clearly consistent with either climate change or land use change being the primary driver.Location South Africa.Methods We categorized recent range changes among 408 South African terrestrial bird species and, using generalized linear mixed models, analysed ecological attributes of those species that have and have not changed their ranges.Results Fifty‐six of the 408 taxa studied have undergone significant range shifts. Most extended their ranges towards the south (towards cooler latitudes, consistent with climate‐change drivers) or west (towards drier and warmer habitats, inconsistent with climate drivers but consistent with land use drivers); very few moved east or north. Both southward and westward movers were habitat generalists. Furthermore, southward movers were mobile taxa (migrants and nomads), whereas westward movers were associated with human‐modified elements in the landscape, such as croplands, plantations or buildings.Main conclusions The results suggest that both land use changes and climate change may simultaneously be influencing dynamic range shifts by South African birds, but separating the relative strengths of these two drivers is challenging, not least because both are operating concurrently and may influence some species simultaneously. Those species that respond to land use change by contracting their ranges are likely to be among the species that will be most impacted by climate change if land use practices with negative impacts are occurring in areas anticipated to become climatic refugia for these species. This highlights a pressing need to develop dynamic models of species’ potential range shifts and changing abundances that incorporate population and dispersal processes, as well as ecological processes that influence habitat suitability.

Our analyses of the incidence of cooperative breeding among South African birds differ from previous studies performed elsewhere in two respects. First, we distinguish between "obligate" (i.e. regular) and "facultative" (i.e. opportunistic) cooperative breeding species (OCS and FCS). Second, we have restricted our analyses to 217 South African bird species considered to be sufficiently well-studied in terms of their basic biology and life-history characteristics. This was done in order to control for the well-known bias against the often poorly-studied avifaunas of extreme environments such as rainforests and deserts. The results of our analysis do not accord fully with those of Australian birds by Ford et al. (1988). Cooperative breeding in South Africa is associated with seasonal environments, whereas in Australia the opposite is the case. Analyses of ecological factors that promote cooperative breeding among South African birds suggest that the evolutionary pathway to obligate and facultative breeding may be fundamentally different. First, OCS live mainly in savanna habitats that have predictable seasonal peaks in food availability, yet where the baseline level of food availability during the nonbreeding season is sufficient to support permanent residence by groups. Small to medium-sized birds of the African savannas are particularly vulnerable to avian predators, and foraging and roosting in permanent groups may enhance their survival. We propose that the benefits of obligate cooperative breeding are derived chiefly from survival of individuals away from the nest (i.e. during the nonbreeding season). Secondly, FCS live largely in unpredictable, seasonal steppe habitats. Under these conditions it may be impossible for birds to maintain permanent group territories, and variation in the tendency to breed cooperatively may depend largely on the opportunistic assessment of environmental conditions. We therefore suggest that birds (i.e. FCS) will opt to breed cooperatively only when conditions are unfavourable for independent breeding, and that the benefits thus accrued are chiefly related to reproduction.

Functional and trophic perspectives on patterns of species occurrences have the potential to offer new and interesting insights into a range of spatially explicit problems in ecology and conservation. We present the function-area relationship (FAR) and explore linkages between functional and taxonomic species richness for South African birds. We first used beak morphology to classify a subset of 151 South African bird species into 18 functional groups and calculated both the species-area relationship and the FAR at quarter-degree resolution for South Africa. The relationship between functional and taxonomic richness by cell was quadratic rather than linear, with considerable scatter around the curve. We next looked at the spatial relationships between taxonomic diversity and response diversity (i.e. diversity within functional groups) using an a priori categorization of nearly all South African birds into nine functional groups. The spatial distribution of response richness also showed considerable variation in relation to taxonomic richness. Our results demonstrate a novel approach to linking taxonomic, functional and trophic patterns in space and suggest a way in which conservation planning, which has traditionally had a taxonomic focus, could formally incorporate a more functional and food-web-based approach.

Until recently, no medicinal uses were recorded for the South African Erythroxylaceae species, although, this family is used world wide in traditional medicine. This study reveals for the first time that Erythroxylum delagoense and Erythroxylum pictum roots were used to treat dysentery and diarrhoea and that Erythroxylum emarginatum leaves decoction was used to treat asthma, kidney problems, arthritis, child bearing problems and influenza in South Africa. To validate some of the medicinal uses, antibacterial testing was done for the first time on all five South African species. Leaf and bark extracts of four of the five South African Erythroxylaceae species ( E. delagoense, E. emarginatum, E. pictum and Nectaropetalum capense ) showed some good antibacterial activities with MIC <1 mg/ml. E. delagoense showed good results against Bacillus subtilis , Klebsiella pneumoniae and S taphylococcus aureus ; E. emarginatum against Klebsiella pneumoniae ; E. pictum against Bacillus subtilis and Klebsiella pneumonia; N. capense against Klebsiella pneumonia . Key words: Antimicrobial activity, Erythroxylaceae, medicinal uses, South Africa.

South African Helichrysum species: A review of the traditional uses, biological activity and phytochemistry

St Lucia Lake on the north coast of Natal, South Africa, has an area of 325 km2 and is the largest estuarine complex in Africa. It consists of a 20 km tidal channel, averagingca. 400 m in width, linking the sea with the non-tidal lake which is H-shaped with a maximum length ofca. 40 km and width ofca. 20 km. Except during flood periods the depth of the lake does not exceed 2 m. The salinity gradient depends on evaporation, the configuration of the mouth and on the input of fresh water from four rivers which discharge into the northern and western areas of the lake. If fresh water input is high, the lake and much of the channel may be fresh. An intermediate stage features a normal salinity gradient while a third stage shows a reversed salinity gradient with salinities in excess of 100‰ in the upper reaches of the system. Changing salinities have marked effects on the biota. Aquatic macrophytes show cycles of appearance and disappearance depending on salinity tolerance and the presence of dormant stages. The resident benthic faunal species go through cycles of range expansion and contraction depending on prevailing salinities and recolonisation by dispersal phases. To date salinities in the southern part of the lake have approached, but not exceeded, lethal levels and this has therefore acted as a reservoir area. Catchment degradation and water abstraction are anticipated to exacerbate future salinity extremes. This has resulted in concern for the long term viability of this Ramsar site which has major southern African populations of hippopotamus and crocodile, provides breeding sites for South African Red Data water bird species and plays an important nursery role for marine fish and penaeid prawns.

The primary purpose of this study is to investigate the extent to which the key elements of talent management (TM) and employee engagement (EO) are being utilized to retain employees at a large South African Company (herein-often referred to as CSA). Skills shortages have become a feature of the South African business environment. As such competition to attract human capital in the form of talented individuals and the ability to retain them have become a major competitive consideration even when compared to other competitive dimensions such as capital, strategy and even research and development. Although the South African Company (CSA), is committed on paper to appointing, developing and retaining talented employees it is unclear as to how successful this strategy is, given the high turnover rates. The study therefore seeks to assess the extent to which talent management as a competitive device is being implemented successfully. Much of the available literature has concentrated on the key strategies that lead to talent management and employees retention in countries and settings that are outside Africa. The lack of scholarly investigation of this phenomenon in Africa where the reality of brain drain is constantly being published, suggests that there is an important lacuna with respect to the African setting and in particular post-apartheid South Africa which has witnessed significant brain drain. There is therefore an important need for such a study in order to inform the African context and specifically the South African environment. The study applies an adapted Gallup Workplace Audit (or GWA) developed by Kahns (1990) and refined by Bhatnagar (2007). The GWA dimensions consist of 12 areas covering retention of employees, business unit productivity, profitability and customer loyalty (Buckingham and Coffman, 1999). It is argued that managers need to attend to these key dimensions in order to ensure better talent management practices. The study undertakes a de-constructivist approach, which entails the use of quantitative research techniques in the form of structured questionnaires based on the Gallup Workplace Audit (GWA). The study utilises a descriptive design in order to ascertain the extent of employee engagement in the case of SA. The study sampled a number of managers and employees at SA to ascertain the extent to which these samples agree that talent management is practiced in this organization. The main finding is that despite CSA’s commitment to retaining talent, this study finds that these employee engagement strategies in a few important instances may only be partially realised. Key words: Employee engagement, talent management, employee retention, gallup workplace audit (GWA), South Africa.

Net Loss? Agrochemicals and Insecticide Resistance in the Fight against Malaria.

The perceived cosmopolitanism of polychaete worms could be an artefact of historical factors such as poor original species descriptions, lack of type material and the European taxonomic bias, to name a few. Thus, it is possible that several cosmopolitan species hide complexes of cryptic and pseudocryptic species. Two putative cosmopolitan species, Platynereis dumerilii and Platynereis australis, collected in South Africa were investigated here (1) to determine whether the South African taxa are conspecific with the morphologically identical taxa from France and New Zealand (the respective type localities of P. dumerilii and P. australis), (2) to compare the South African species morphometrically to determine whether their morphological characters are reliable enough to separate them, and (3) to investigate whether these species have geographically structured populations along the coast of South Africa. Molecular data (COI and ITS1) confirm that P. dumerilii and P. australis do not occur in South Africa. Instead, the South African taxon formerly thought to be Platynereis dumerilii is new and is described here as Platynereis entshonae, sp. nov.; the identity of the other South African species is currently unresolved and is treated here as Platynereis sp. Surprisingly, Platynereis massiliensis (type locality: Marseilles) nested within the South African Platynereis sp. clade but, since it is part of a cryptic species complex in the Mediterranean, the name is considered doubtful. Morphological characters traditionally used to define these South African Platynereis species are not reliable as predefined morphological groupings do not match phylogenetic clades and principal component scores revealed no separation in morphological characters that could distinguish between them. Haplotype networks and phylogenetic trees revealed that P. entshonae, sp. nov. and Platynereis sp. have geographically structured populations along the South African coast. http://zoobank.org/urn:lsid:zoobank.org:pub:6E36A210-9E48-430F-8A93-EDC27F0C5631

Invasive alien species (IAS) pose a serious threat to global biodiversity, and unravelling the mechanisms driving their expansion across new ranges remains an important challenge for ecosystem conservation. Assessing similarities and differences in species’ traits and phenotypic fitness proxies between native and invasive populations can show how species may have locally adjusted in the new areas and their capacity to expand further. Here, we compare basal metabolic rates (BMR), body and nutritional condition (based on feather proxies) and body size between native (South Africa) and invasive (northern and southern Portugal) common waxbills (Estrilda astrild). As expected, given prevailing ambient temperatures - similar between South Africa and northern Portugal but hotter in southern Portugal - our results showed that mass-independent BMR was similar between individuals from South Africa and northern Portugal, but lower in individuals from warmer southern Portugal. However, contrary to our expectations based on the enemy release hypothesis, feather density was higher in South African birds, challenging the assumption that invasive populations outperform their native counterparts. Additionally, feather growth rates trade-off with feather quality in the introduced populations, indicating that they may face energetically challenging environments in their invaded range. Common waxbills in South Africa were larger than those in Portugal, but further analyses showed that these size differences between native and invasive birds may be influenced by introduction history rather than ecological factors alone. This study highlights the importance of considering both native and invaded ranges when studying invasive species and provides insights into the strategies used by waxbills to thrive in different environments.

Global food security faces challenges arising from population growth, climate change, and the prevalence of monoculture agriculture. In addressing these concerns, Bambara groundnut (Vigna subterranean (L.) Verdc.) emerges as a promising crop due to its nutritional richness and resilience in marginal environments. Despite its potential, research gaps persist, particularly in the context of South Africa. The study aimed to evaluate the performance and stability of Bambara groundnut genotypes in two South African agroecological environments. Field trials were conducted at Brits and Ukulinga, with data collected on grain yield, hundred-seed weight, and other agronomic traits. Genotypes Acc 179, 184, and 82 demonstrated significant stability and high yields across both locations, showing promise for future breeding programs. The results suggest that these genotypes can adapt to diverse agroecological areas, enhancing Bambara groundnut production in South Africa. Future research should focus on breeding efforts to further improve crop resilience.

The medicinal uses, chemistry and phylogenetic relationships of ethnobotanically relevant South African Stachys species.

Multi-purpose tree species contribute towards the livelihoods of people in rural communities. Bark, roots, fruits and seeds of several South African indigenous tree species are harvested to use as medicines, food and/or beverages. The woody parts of the same trees are often also used as firewood or building material, or for the production of carved household products. Many South African tree species have specific habitat requirements that limit their distribution, and several also have low reproduction and growth rates. South Africa has 44 indigenous tree species that are protected by law. South Africa's environmental legislation prohibits the harvesting of protected plants or plant parts, however, legislation merely slowed down the rate of increase in exploitation without providing a sustainable solution. The management of indigenous tree species in their natural habitats is essential, however, the cultivation of culturally important protected multi-purpose tree species should also be promoted considering that multi-purpose tree species are more vulnerable to extinction than single-use tree species. This review therefore discusses the ethnobotanical uses, management and the cultivation possibilities/methods of selected indigenous protected multi-purpose South African tree species. The review further provides pharmacological and toxicological reports of the selected species. The selection criteria included the tree species' multiple uses, its protected status, its conservation status and its cultural importance as a medicine. One single-use protected indigenous tree species, Warburgia salutaris, is included in this review due its cultural importance as a medicine.

Economic analysis of agrochemical use for weed control in field-grown celery: A case study for Turkey

Genome size (C-value) and the percentage of adenine and thymine nucleotides in the genome (AT content) are fundamental characteristics of every species, and very important parameters in molecular cytogenetic and phylogenic studies, and for the progress of whole-genome sequencing. In this study, the C-value and AT content of nine abalone species inhabiting the Northwest Pacific (around Japan), Southeast Asia, South Africa, and Oceania were determined using flow cytometry. C-value ranged from 1.32 pg for Haliotis varia (Southeast Asia) to 2.01 pg for Haliotis laevigata (Oceania), and AT content ranged from 58.0% for Haliotis planata (Southeast Asia) to 66.3% for Haliotis diversicolor aquatilis (Southeast Asia). Reported chromosome numbers ranged from 2n = 32 to 36, and were higher in Oceanian, South African, and Northwest Pacific species (2n = 36) compared with the Southeast Asian group (2n = 32). This increase of chromosome number in the Oceanian species seems to be related to an increase in the DNA amount, unlike that of Haliotis midae (South African species). An increase of the C-value associated with an increase in DNA amount was also shown in the North Pacific group. These results suggest that increases in the DNA amount occurred independently in the ancestor of each of the different lineages.