“Cast away” at Home: Exoticising the Local on Survivor South Africa Immunity Island

Parasitism and introduced species: epidemiology of trematodes in the intertidal mussels Perna perna and Mytilus galloprovincialis

Spawning patterns of shallow-water hake (Merluccius capensis) and deep-water hake (M. paradoxus) in the Benguela Current Large Marine Ecosystem inferred from gonadosomatic indices

<p>Strategic bridge inspections undertaken on the beautiful South African wild coast highlighted the legacy of past generations in providing state-of-the-art bridge infrastructure that still serves a functional and aesthetic purpose. The paper focuses on four large arch bridges in South Africa with arch spans ranging from 100m up to 272m, constructed between 1956 and 1983, the Bloukrans River Bridge, the Groot River Bridge, the Storms River Bridge, and the Bobbejaans River Bridge. These bridges, located on the N2, are integral to the national transport network, represent significant feats of structural engineering for their time. Concrete Arch bridges date back thousands of years and have always captured the imagination in how they elegantly and effectively transfer significant forces through their arches to their foundations. The close concentration of these bridges on the wild coast, built within 30 years of each other, necessitated a review of the evolution of design and construction methodologies used at the time. Construction of the Storms River Bridge was completed in 1956. The arch, built in four quarters, two on each bank, and lowered in the middle, was a significant achievement given the contractor did not have the benefit of modern sophisticated instrumentation and formwork systems. Thereafter, the other three bridges evolved their construction methodology utilizing highlines and constructing segments of the arches until the two halves meet at the centre. While the bridges had notable unique construction methodologies. The bridges also possess different structural articulation, the Storms River bridge has inclined spandrel supports that radiate outward from the main arch rib, while the other three have vertical spandrel supports that radiate outward from the main arch rib. It is evident that the evolution of design and construction was driven by the economics of building the bridges rather than any defects identified in earlier designs, highlighting their structural competence of “getting the basics right”.</p>

We surveyed six protected areas along the Wild Coast of the Eastern Cape, South Africa, to determine general herpetofaunal diversity as well as the representation of species of special conservation concern. Visual encounter survey methods and standard Y-shape trap arrays were used to conduct surveys from 2011 to 2013. A total of 59 species (22 amphibians and 37 reptiles) were recorded. A number of previously unknown populations of threatened species and one potential novel species were discovered in these protected areas, and the known ranges of several other species were extended. A total of 243 quarter-degree grid-cell unit records were documented, of which 90 (23% amphibians and 50% reptiles) represented the first records for the area. Amphibian and reptile diversity increased along the coast and a number of species of conservation concern were well represented in current protected areas. Our study provides a comprehensive amphibian and reptile checklist for an under-sampled region and highlights the importance of baseline data for improving conservation management.Conservation implications: Small protected areas play an important role in conserving a number of threatened herpetofaunal species along the Wild Coast. The region is currently under significant and increasing pressure from anthropogenic-induced environmental degradation, which affects biodiversity and subsequently the local inhabitants. The information presented here represents an important baseline for future conservation management.

This paper explores some aspects of the contradictory and complex cultural politics of eco-tourism on foot in the Eastern Cape, South Africa, through an auto-ethnographic case study. Guided by a local Mpondo leader, we hiked the Wild Coast trail from Port St. Johns to Coffee Bay in March 2024. Over five days and 75 kilometres, this journey provided not only an intimate encounter with the natural beauty of the region but also glimpses into the lives of the communities that inhabit and steward this landscape. Employing ethnographic observation, we analyzed the interplay between walking as a leisure activity and its deeper socio-political dimensions. Drawing from sensory and embodied experiences, captured through voice notes, photographs, and videos, we argue walking offers an opportunity to gain deeper insight into the politics of privilege and to foster embodied connections that offer temporary opportunities to transcend traditional tourist dynamics. Hiking can deepen visitors’ learning and care while creating sustainable socio-economic opportunities for local guides and communities, and as such is a useful topic for better understanding the shape of inequality in South Africa today.

We examined spatial variability in meristic and morphological characteristics of the branchial basket of sardine Sardinops sagax collected from four geographical regions around the southern African coast, namely Namibia and the South African west, south and east coasts. Our analysis tested the hypothesis of three putative sardine stocks off South Africa, one in each of the three geographical regions. We therefore collected fish data from Namibia to compare with South Africa, because sardine from the two countries are considered to be separate stocks. Morphometric measurements (gill arch length and gill raker spacing) and meristic data (number of gill rakers) were collected from the left side of the first gill arch from a total of 377 sardine, approximately equally divided between the regions. A multivariate general linear model with caudal length as covariate was used to assess differences among fish from the four regions and significant differences were observed, although not always consistently across all fish size classes. Small South Coast sardine had shorter gill arches than small West Coast sardine, but adults had gill arches of similar length, longer than those from Namibia and the East Coast. Small sardine from the South Coast had fewer gill rakers than small sardine from the West Coast, but larger fish had similar numbers of gill rakers, significantly more than sardine from Namibia and the East Coast. Sardine from the West and South coasts had similar gill raker spacings, which were smaller than those of fish from the East Coast and Namibia. Despite spatially and particularly temporally unbalanced sampling, we consider that these differences provide evidence of spatial variation in Benguela sardine phenotype and that it would support the hypothesis of discrete sardine stocks off Namibia and South Africa. The results are consistent with the hypothesis of three sardine stocks within the southern Benguela.

Filtration, feeding behaviour and their implications for future spread: A comparison of an invasive and native barnacle in South Africa

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.

Historical and recent evidence recorded along the South African coast suggests that five tsunami events have occurred since 1960. These were mostly associated with trigger mechanisms associated with sources of remote submarine seismicity along far-field subduction zones and local atmospheric disturbances (meteotsunami). The passive margin of the South African West Coast, and the broad Agulhas Bank spanning the South- and Southeast coasts, have contributed to an increased susceptibility to inundation of waves in the adjacent low-lying coastal areas in these regions. In the published models and empirical studies for South Africa, the bathymetry and orientation of Port Elizabeth Bay is seen to amplify effects of a tsunami wave. Other regions including the Cape Town and St Helena Bay areas are also vulnerable to coastal inundation through the data generated in this study. The methodology presented here provides a simple means of determining the susceptibility of coastal areas to significant inundation by far-field tsunamis.

The deep-water Cape hake, Merluccius paradoxus, is one of two hake species found off South Africa and Namibia. In the past it was assumed that there were separate stocks of M. paradoxus off Namibia, and off the west and south coasts of South Africa, but there were also indications that the assumption might not be true. In this study, the stock integrity of M. paradoxus in the Benguela was investigated using a holistic stock identification approach. The approach involved analyses of the temporal and spatial distribution of M. paradoxus off Namibia and the South African west coast. It also involved an investigation of published characteristics of M. paradoxus such as genetic identification, distribution of eggs and larvae, and of parasites, etc. From this information, it was suggested that the Benguela supports a single stock of M. paradoxus, which spawns on the Agulhas Bank and with nursery areas off the South African west coast and southern Namibia. Adults of the species are widespread throughout the region. If there is a single stock in the Benguela, management strategies and assessment by South Africa and Namibia could need revisiting, for the stock is currently treated as two national entities, and is assessed and managed independently.

General linear models (GLMs) were used to determine the relative importance of interspecific, ontogenetic and spatial effects in explaining variability in stable isotope ratios of nitrogen (δ(15) N) and carbon (δ(13) C) of the co-occurring Cape hakes Merluccius capensis and Merluccius paradoxus off South Africa. Significant GLMs were derived for both isotopes, explaining 74 and 56% of observed variance in Merluccius spp. δ(15) N and δ(13) C, respectively. Spatial effects (west or south coast) contributed most towards explaining variability in the δ(15) N model, with Merluccius spp. off the west coast having higher (by c. 1.4‰) δ(15) N levels than Merluccius spp. off the south coast. Fish size and species were also significant in explaining variability in δ(15) N, with both species showing significant linear increases in δ(15) N with size and M. capensis having higher (by c. 0.7‰) δ(15) N values than M. paradoxus. Species and coast explained most and similar amounts of variability in the δ(13) C model, with M. capensis having higher (by c. 0.8‰) δ(13) C values than M. paradoxus, and values being lower (by c. 0.7‰) for fishes off the west coast compared with the south coast. These results not only corroborate the knowledge of Merluccius spp. feeding ecology gained from dietary studies, in particular the ontogenetic change in trophic level corresponding to a changing diet, but also that M. capensis feeds at a slightly higher trophic level than M. paradoxus. The spatial difference in Merluccius spp. δ(15) N appears due to a difference in isotopic baseline, and not as a result of Merluccius spp. feeding higher in the food web off the west than the south coast, and provides new evidence that corroborates previous observations of biogeographic differences in isotopic baselines around the South African coast. This study also provides quantitative data on the relative trophic level and trophic width of Cape hakes over a large size range that can be used in ecosystem models of the southern Benguela.

Local ecological knowledge (LEK) can shed light on ecosystem change, especially in under- researched areas such as South Africa's Wild Coast. However, for ecosystem planning purposes, it is necessary to assess the accuracy and validity of LEK, and determine where such knowledge is situated in a community, and how evenly it is spread. Furthermore, it is relevant to ask: does LEK add value to science, and how do science and local knowledge complement one another? We assessed change in woodland and forest cover in the Nqabara Administrative Area on South Africa's Wild Coast between 1974 and 2001. The inhabitants of Nqabara are Xhosa-speaking people who are highly dependent on natural resources for their livelihoods. More recently, however, infrastructural development has influenced traditional lifestyles at Nqabara, although poverty remains high and formal education levels low. We assessed LEK about changes in woodland and forest cover over the past 30 years by interviewing 11 local experts, who were recognized as such by the Nqabara community, and 40 senior members of randomly selected households in each village. We also analyzed land-cover change, using orthorectified aerial photos taken in 1974 and 2001. Forest and woodland cover had increased by 49% between 1974 and 2001. The 11 had a nuanced understanding of these changes and their causes. Their understanding was not only remarkably consistent with that of scientists, but it added considerable value to scientific understanding of the ultimate causes of land-cover change in the area. The experts listed combinations of several causal factors, operating at different spatial and temporal scales. The 40 randomly selected respondents also knew that forest and woodland cover had increased, but their understanding of the causes, and the role of fire in particular, was somewhat simplistic. They could identify only three causal factors and generally listed single factors rather than the combinations of factors listed by the experts. In some instances, their understanding even appeared to be seriously flawed. In contemporary Xhosa society, ecological knowledge is unevenly spread and held by individuals rather than by groups. Therefore, it is important to work with experts rather than randomly selected individuals in ecological studies that incorporate local knowledge. Expert local knowledge adds value to science by providing detailed insights into the ultimate causes of change, and by contributing a rare historical perspective. Scientists add value to local knowledge through their ability to study and predict obscure processes such as the impact of atmospheric change on vegetation. Scientists must, however, acknowledge that positivist studies that compare local knowledge to science are fraught with ethical and methodological challenges. Certain aspects of local knowledge, particularly in terms of fire, are sacred and do not have the same origins as Western science. Local knowledge and science can complement one another, but we advise against integrating them in a way that co-opts local knowledge for scientific purposes.

Scaevola plumieri is an important pioneer on many tropical and subtropical sand dunes, forming a large perennial subterranean plant with only the tips of the branches emerging above accreting sand. In South Africa it is the dominant pioneer on sandy beaches along the east coast, less abundant on the south coast and absent from the southwest and west coasts. Transpiration rates (E) of S. plumieri are predictably related to atmospheric vapour pressure deficit under a wide range of conditions and can therefore be predicted from measurement of ambient temperature and relative humidity. Scaling measurements of E at the leaf level to the canopy level has been demonstrated previously. Using a geographic information system, digital maps of regional climatic variables were used to calculate digital maps of potential transpiration from mean monthly temperature and relative humidity values, effectively scaling canopy level transpiration rates to a regional level. Monthly potential transpiration was subtracted from the monthly median rainfall to produce a map of mean monthly water balance. Seasonal growth was correlated with seasonal water balance. Localities along the coast with water deficits in summer corresponded with the recorded absence of S. plumieri, which grows and reproduces most actively in the summer months. This suggests that reduced water availability during the summer growth period limits the distribution of S. plumieri along the southwest coast, where water deficits develop in summer. Temperature is also important in limiting the distribution of S. plumieri on the southwest coast of South Africa through its effects on the growth and phenology of the plant.

Abstract. Scaevola plumieri is an important pioneer on many tropical and subtropical sand dunes, forming a large perennial subterranean plant with only the tips of the branches emerging above accreting sand. In South Africa it is the dominant pioneer on sandy beaches along the east coast, less abundant on the south coast and absent from the southwest and west coasts. Transpiration rates (E) of S. plumieri are predictably related to atmospheric vapour pressure deficit under a wide range of conditions and can therefore be predicted from measurement of ambient temperature and relative humidity. Scaling measurements of E at the leaf level to the canopy level has been demonstrated previously. Using a geographic information system, digital maps of regional climatic variables were used to calculate digital maps of potential transpiration from mean monthly temperature and relative humidity values, effectively scaling canopy level transpiration rates to a regional level. Monthly potential transpiration was subtracted from the monthly median rainfall to produce a map of mean monthly water balance. Seasonal growth was correlated with seasonal water balance. Localities along the coast with water deficits in summer corresponded with the recorded absence of S. plumieri, which grows and reproduces most actively in the summer months. This suggests that reduced water availability during the summer growth period limits the distribution of S. plumieri along the southwest coast, where water deficits develop in summer. Temperature is also important in limiting the distribution of S. plumieri on the southwest coast of South Africa through its effects on the growth and phenology of the plant.

New, large-scale collections have been made of marine benthic macroalgae (seaweeds) on the east coast of South Africa, and the distributions of shallow-water species were analyzed in detail by multivariate, clustering and β-diversity methods. The two northernmost sites are distinct, with a predominance of tropical species, and it is concluded that the changeover from a tropical Indian Ocean flora to a temperate South African flora occurs most rapidly in the vicinity of St. Lucia, 135 km south of the Mozambique border. It is imperative that all future biogeographical studies on the South African inshore marine biota include detailed collections north of St. Lucia. The remaining 440 km of the South African east coast (southern and central Kwazulu-Natal Province) is populated by a mixture of tropical and temperate elements, with only 2% endemism in this data set. This, thus, represents a true overlap region, with relatively equal numbers of species with affinities in the temperate Agulhas and tropical Indo–West Pacific floras, rather than a distinctive sub-tropical marine province, as the South African east coast is considered to be by most previous authors. The distinction between this overlap region and the south coast (Agulhas) region proper is not as clearly distinct. The change from a temperate to a tropical flora shows a relative increase in green algae from 15% to 25% of the species present. Criteria for the delineation of marine biogeographical regions are critically discussed, and it is concluded that the monitoring of distributions of all species, including rare species, is necessary. This is particularly relevant with regard to using these data to assess effects of potential changes in seawater temperature, including those which may be caused by global warming. Criteria for the delimitation of biogeographic entities such as "marine provinces" need to be clearly spelt out in all investigations.