West Coast Of South Africa Research Articles

Discovery of live material of Marginella (Roseamarginella) namaqua

Recently (March 2024) the authors undertook another field trip to the Kalahari and northern West Coast of South Africa. In March 2021 the authors had an expedition through the Kalahari, Karoo and West Coast of South Africa that took them to a little-known fisher’s town, Hondeklip Bay. For background on the town, in 1846, Thomas Grace (a ship’s captain) discovered a small natural harbor and he established a trading station, naming the town after a gneiss rock which vaguely resembles a dog. The name of the town is “Hondeklipbaai”, an Afrikaans name that translates as “dog stone bay” in English. It became the preferred harbor of export for copper ore, until the harbor in Port Nolloth was developed in the 1850s. Alluvial diamond-mining operations started in the area in 1970 and constitutes the main business of mines in that area of the Northern Cape (Mohomed 2006). Just north of the Hondeklip Bay lighthouse a lesser-known bay is found, “Moordenaarsbaai”, where the study material that were used for describing the species was collected. Unfortunately, at that stage the authors could only spend one and a half day in the area, and no live material could be collected due to the neat tide and stormy seas. The recent trip to Hondeklip Bay by the authors did not disappoint, the tide timing was perfect with springtide and good weather. A bit of scratching between the rocks and sea grass in rough black-muddy sand revealed three live specimens. What makes this special is that this species so far only been found in this area and this is the first livematerial.

Geological characteristics and seismic identification of reservoirs in the Colorado Basin off the Atlantic coast of Argentina

Abstract The Colorado Basin is a hot exploration frontier basin conjugated with the southwest coast of Africa which has undergone four evolutionary stages: Carboniferous-Jurassic pre-rift, Jurassic-Early Cretaceous rift, Late Cretaceous transition and passive marginal drift since Paleocene. Major oil and gas discoveries have been made in the conjugated Orange Basin in recent years, including the Graff field and Venus field discovered in 2022 with recoverable reserves of 550 Mboe and 2.3 Bboe, respectively. This indicates that the basin has good oil and gas exploration potential. Based on the analysis of drilling data and seismic data, it is concluded that the basin has a mature oil-gas generation system and better reservoir conditions. The pre-rift and syn-rift source rocks are confirmed by 5 Wells with oil and gas shows in the shallow water shelf, and all have entered the hydrocarbon generation threshold. Reservoir distribution and trap-sealing conditions have become key factors in oil and gas exploration. this paper describes the reservoir characteristics in the drilling data, and extrapolates the seismic reflection characteristics of the same strata, and predicts the reservoir distribution in the unexplored area of the basin. The reservoir lithology and sedimentary facies are analyzed based on the gamma logging curves. Reservoir identification and reasonable prediction on seismic profile are mainly determined by seismic reflection amplitude and horizon calibration. The basin has three sets of reservoirs, namely, pre-rift Permian underwater fan sandstone, Lower Cretaceous alluvial fan sandstone of syn-rift period and Upper Cretaceous Colorado Formation shallow marine sandstone of transitional period. Among them, Colorado Formation sandstone reservoir has the best physical property conditions, with a maximum porosity of 32% and a thickness of 1000m. The Cretaceous and Paleogene turbidite sandstone of slope fan facies are potential reservoir in the deep waters, which mainly form litho-stratigraphic traps in the continental slope.

Altered temperature and restricted food supply reduce pH tolerance in both young and adult ascidians

ABSTRACT Ocean acidification poses a threat to marine ecosystems. Understanding of how responses to acidification differ among life stages and how they are moderated by co-occurring stressors remains limited. This study investigated the tolerance of ascidians to acidification, under regional cooling, as experienced along the west coast of South Africa and in other eastern boundary upwelling systems. Critical pH minima (CpHmin) were established for young and adult Ciona robusta and young and adult colonies of Diplosoma listerianum, Botryllus schlosseri, Botryllus gregalis, under restricted and unrestricted food supply, at two temperatures (13°C (current) and 9°C (future cooling)). pH was reduced at a rate of 0.1 units per day, starting from the current condition of 7.9 pH. For all species, responses to decreasing pH were affected by life stage, temperature and food supply. Young individuals and young colonies were least tolerant to acidification. Regardless of life stage, cooling reduced pH tolerance, as did restricted food supply. These results suggest that tolerance to acidification is lowest during early life stages and will be exacerbated by climate change induced cooling. However, high productivity in upwelling regions may result in high food supply that could ultimately buffer against the negative effects of cooling on pH tolerance.

Habitat changes in response to pressures in the Verlorenvlei Estuarine Lake, South Africa

Verlorenvlei is a globally important RAMSAR wetland on the arid west coast of South Africa. A prolonged drought between 2016 and 2021 and increasing competition for water from the agricultural sector resulted in extremely low water levels. We used historical aerial and satellite imagery from 1942 and rainfall and water level data for the past 50 years, to assess habitat changes within the estuarine functional zone of the Verlorenvlei Estuarine Lake. Prior to the drought, lake water levels and water surface area remained stable (1113 ± 27 ha (SE)). Since then, there has been a 64% decrease in open water area, exposing 193 ha of sandbanks, of which 190.9 ha were hyper-sulfidic pyrite-rich. The water in the lower lake was hypersaline ( >100), and in the middle, it was acidic (pH<3). The low water level plus sediment and nutrient input from surrounding agriculture resulted in a localised increase in reeds. Additional pressures, such as fires, have reduced the above-ground biomass of reeds and sedges, potentially altering surface morphology and reducing stored carbon. Despite flooding and filling up in June 2023, the lake remained in an acidic state (3.9–4.3). Similar low-lake level, hypersaline and acidic conditions are predicted to become more common under future climate change scenarios where aridity and extreme weather events are anticipated. Inflow of fresh water into the estuary and control of farming practices are required to keep the Verlorenvlei in a functional state, with long-term monitoring necessary to assess the ecological condition in response to restoration actions.

Variable foraging and flower probing behaviour of sunbird pollinators of the South African Pelargonium fulgidum

ABSTRACT Whether foraging sunbird pollinators hover or perch, the type of perch used, and the direction of flower probing are generally thought to be determined by matching shapes of decurved bird bills and curved flower tubes, as well as inflorescence architecture. However, few studies have objectively quantified aspects of sunbird foraging behaviour to test predictions based on adaptive trait matching. I investigated sunbird foraging in a population of Pelargonium fulgidum, a species with slightly upcurved flowers borne on upward-oriented peduncles, which grows along the west coast of South Africa. Long-range photographs revealed that Cinyris chalybeus, a sunbird species with a slightly decurved bill, hovers or perches during foraging, and uses both the inflorescence and alternative vegetation structures as perch. Contrary to previous suggestions, both male and female sunbirds probe flowers from either of two alternative directions (sternotribic versus nototribic) in more or less equal proportions, and frequently display flexibility in both foraging behaviour and flower probing direction. Predominant or complete sternotribic and nototribic flower probing were explained by hovering versus use of an inflorescence perch respectively, whereas use of an alternative perch resulted in similar proportions of each mode of flower probing. The number of flowers per visited inflorescence and number and proportion of probed flowers did not vary with foraging behaviour or flower probing direction. Although certain foraging behaviours resulted in predictable flower probing directions, variation in foraging behaviour and the presence of many alternative perches provided by vegetation surrounding P. fulgidum plants resulted in variability in flower probing direction that appears not to affect foraging efficiency. Relatively weak reciprocal curvature of flower tube and sunbird bill, resulting in easy access to nectar from multiple feeding directions, likely facilitates flexible foraging. This study shows that environmental context may facilitate more complex foraging behaviour than that predicted by adaptive trait matching.

'n Geografiese ontleding van eksplorasie in die sentraal-Weskusgebied van Suid-Afrika (1660 tot die era van die veeboerpionier)

J.D. Overton developed theoretical frameworks incorporating the different components and linkages in the process of exploration. In this article one of his models is applied in connection with the early Stages of exploration in the central part of the west coast of South Africa, which includes the magisterial districts of Clanwilliam, Vredendal, and Vanrhynsdorp. It is concluded that exploration of the central part of the west coast was mainly undertaken as the result of economical demand factors which came into being. Although the original demand factors did not seem to be satisfied fully in this area, new demand factors appeared which gave way to re-assessment of the central part of the west coast. As the area was able to provide for this new demand, the result was the final settlement of Whites.

Kelp holdfasts in the Great African Seaforest provide habitat for diverse assemblages of macroinvertebrates

Kelp forests along the southwestern and west coasts of South Africa, dominated by the species Ecklonia maxima and Laminaria pallida, are locally termed ‘the Great African Seaforest’. They form 3-dimensional biogenic habitats that provide 4 distinct microhabitats—canopy, fronds, stipe and holdfast—with the latter typically supporting the highest abundance and diversity of associated macroinvertebrates. The macrofauna inhabiting kelp holdfasts in South Africa have rarely been studied, resulting in a near complete lack of baseline data. In this study, macrobenthic assemblages from 40 E. maxima holdfasts were examined over 2 marine ecoregions and 4 locations. Macroinvertebrates were identified and counted for univariate and multivariate analyses using family-level data. A total of 120 families from 9 phyla were identified and were generally dominated by Arthropoda (48 families), Annelida (24 families) and Mollusca (23 families). Marine ecoregion had no significant effect on composition of macroinvertebrate assemblages, whereas location had a significant effect. There was no significant relationship between holdfast volume and macroinvertebrate diversity or abundance, suggesting that other environmental and physicochemical factors are important in determining community structure. This study serves as a baseline for future research aimed at understudied holdfast macroinvertebrate communities in the Great African Seaforest.

Calcareous termite mounds in South Africa are ancient carbon reservoirs

Ecosystems that offer carbon sequestration by leaching bicarbonate to groundwater are valuable natural capital. One region that may offer this service is the west coast of South Africa. Over 20 % is covered by soil mounds (“heuweltjies”) up to 40 m diameter, 2 m high, inhabited by the southern harvester termite Microhodotermes viator and enriched in soil organic and inorganic carbon and soluble minerals. We aimed to generate radiogenic and stable isotope data for soils and groundwater in a region where these data are absent, to 1) verify the atmosphere-soil-groundwater link, and 2) resolve the timing and pattern of calcite dissolution and water infiltration in the landscape. Results show that soil and groundwater sulfate have the same marine aerosol source. Episodic calcite dissolution in mound centers, which increased during periods of global cooling, has been set against background input of marine aerosols since before the Last Glacial according to radiocarbon (14C) ages. Our data push back soil organic carbon 14C ages of inhabited termite mounds to 13-19 ka (kiloannum, thousand years before present), nest carbonate 14C ages to 33 ka, and mound soil carbonate 14C ages to 34 ka, making these the oldest active termite features ever dated. These ages are consistent with soil organic carbon and carbonate 14C ages of regional, non-mound, coastal petrocalcic horizons formed by accumulation of carbonate leached from their overlying aeolian dune fields. Harvesting activities of termites inject younger organic material around nests >1 m deep, leading to continuous renewal of important soil carbon reservoirs at depth. Termite bioturbation increases the system's ability to dissolve carbonate. The central, bioturbated part of the mounds have greater infiltration depths and greater calcite dissolution, whereas surrounding soils experienced more surface runoff. Calcareous termite mounds offer a mechanism to sequester CO2 through dissolution and leaching of soil carbonate-bicarbonate to groundwater.

Wind energy potential of weather systems affecting South Africa’s Eastern Cape Province

AbstractAs a percentage of the total global energy supply, wind energy facilities could provide 10% of the total global energy supply by 2050 as reported in IEA World Energy Outlook (2022). Considering this, a just transition to renewable and sustainable energy in South Africa is a genuine possibility if steps are taken immediately to achieve this. The Eastern Cape Province exhibits a strong wind resource which can be exploited towards expediting such a just energy transition. No research and related modelling have, to date, been undertaken in quantifying and relating the detailed P50 energy yield analyses of representative wind energy facilities in temporal and spatial dimensions to the occurrence of specific synoptic types in South Africa. To quantify this energy meteorology climatology for a suitably sized geospatial area in the Eastern Cape Province of South Africa (spatial focus area, latitude −30 to −35, longitude 20 to 30), the approach of using self-organising maps is proposed. These maps are used to identify the most common synoptic circulation types occurring in the Eastern Cape and can subsequently be mapped onto an equivalent time resolution wind energy production timeseries calculated based on probable wind energy facility sites. This paper describes comprehensive methodologies used to model the wind energy facilities, calculate with high confidence the P50 energy production, and then identify the predominant synoptic weather types responsible for the wind energy production in this spatial focus area. After quantifying the energy production, running a self-organising map software generates a purposely selected 35 node map that characterises archetypal synoptic patterns over the 10-year period. The synoptic types can be ranked by the highest energy production. It is shown that in this spatial area, monthly wind energy production is higher during the winter months. When the well-established high-pressure cells move northward, synoptic types associated with higher energy production are frequent and include tropical and temperate disturbances across South Africa, patterns resembling a ridging anticyclone off the west coast of South Africa and low-pressure cells occurring to the north and south. Low energy producing patterns show characteristics of the high-pressure cells moving southwards producing fine weather and mildly disturbed conditions. The purpose of this methodology is that it provides the foundation required to derive long-term frequency changes of these synoptic weather systems using global climate model ensembles and thus changes in wind energy production.

High‐Resolution Coccolithophore Morphological Changes in Response to Orbital Forcings During the Early Oligocene

AbstractThe global climate of the early Oligocene was characterized by initiated Antarctic glaciation and meridional overturning circulation, which then led to profound eutrophication in the upper ocean. Generating a high‐resolution coccolith record helps to understand the responses of marine phytoplankton to the newly established environment. Using highly resolved (∼6 kyr time‐resolution) marine sediment samples from Deep Sea Drilling Project Site 522 in the South Atlantic Ocean, we conducted a comprehensive morphological study on coccoliths from the genera Reticulofenestra, Dictyococcites, and Coccolithus, which dominated the study interval between ∼33.1 and 32.8 Ma. Our results showed that the size variations of the three measured genera were significantly correlated (p < 0.01) with each other, indicating homogeneous responses to the environmental changes. Moreover, spectrum analysis on integrated morphologic data of all measured coccoliths showed distinct obliquity (∼40‐kyr) and precession (∼23‐kyr and ∼18‐kyr) cycles. We suggest that these variations were mainly driven by temperate, short‐term ecological fluctuations, which periodically altered the nutrient conditions in the common living habitats of the studied coccolithophores. We proposed two tentative explanations focusing on the obliquity signal. First, the cyclic variation could result from obliquity‐modulated changes in ice volume and variations in ocean circulation intensity, which influenced nutrient export from deep waters to the upper ocean. Alternatively, the changes in coccolith size may indicate the strength of seasonality that influenced upper ocean mixing on the west coast of South Africa.

Spatio-temporal relationships between larval fishes and zooplankton in cool-temperate estuaries of South Africa emphasizing the importance of mesohaline zone interactions

A conceptual model for cool-temperate South African estuaries has been proposed to explain the interactions between zooplankton and larval fishes based on small-scale biological processes. Larval fishes and zooplankton data from nine south and west coast South African estuaries were analyzed in terms of the cumulative density of all species and the density dynamics of the dominant taxa in each group. Larval fish and zooplankton density were positively correlated and varied across seasons, peaking simultaneously in summer, although zooplankton also peaked during the stable conditions of the closed phase of some estuaries. Plankton density was positively correlated with salinity and water temperature and negatively correlated with turbidity. The mesohaline zones of estuaries are highlighted as supporting plankton productivity maxima. These results were attributed to the summer peak in plankton productivity coinciding with the lower rainfall, higher temperatures, and clearer waters that are often typical of the dry summers on the south and west coasts of South Africa. Correlation between selected predator, competitor, and prey species supported the hypothesis that estuaries exhibit extensive reciprocal trophic relationships permitting an ideal feeding environment, which maintains a positive relationship between overall larval fish and zooplankton abundance.

Osteohistology and palaeobiology of giraffids from the Mio-Pliocene Langebaanweg (South Africa).

The reconstruction of life history traits, such as growth rate, age at maturity and age at death can be estimated from the histological analysis of long bones. Here, we studied 20 long bones (metapodials, tibia and femora) of Sivatherium hendeyi and Giraffa cf. Giraffa jumae recovered from the Miocene-Pliocene locality of Langebaanweg on the West Coast of South Africa. We analysed the long bone histology and growth marks of juvenile and adult specimens of these taxa. Our results show that bone tissue types and vascular canal orientation varies during ontogeny, as well as between the different skeletal elements, and also across single cross sections of bones. Majority of our specimens appear to be still growing, with only an adult metacarpal of S. hendeyi being skeletally mature as indicated by the presence of an outer circumferential layer. We propose that the growth marks preserved in the cortices of the bones studied are most likely related to multiple catastrophic events as opposed to being annual/seasonal.

Invasion of rocky shores by a mytilid mussel reveals an abundant‐centre distribution coupled with moderate increases in densities at its absolute range limits

AbstractSemimytilus patagonicus is an invasive mussel on the coast of southern Africa and has extended its range in recent years. We asked whether its distribution and abundance are consistent with the abundant‐centre hypothesis (ACH). Marginal populations were located by monitoring 33 rocky shore sites in South Africa and southern Namibia in 2021. This revealed no changes to its distributional limits since 2020. At nine of these sites, population demography was measured to allow a comparison of their densities and size structure. Four were central populations on the west coast of South Africa (including the site where the species was first detected in 2009). Four were marginal populations in South Africa: two towards the cold range edge in the north and two towards the warm range edge to the south. The ninth population was in southern Namibia, representing a recent invasion event first detected in 2014. Across the species' South African range, the distribution of its abundance was generally consistent with the ACH, with the greatest abundance at its range centre and a gradual decrease towards the range edges. However, the ultimate marginal population at both its cold and warm range edges showed moderate upticks in abundance compared to the penultimate marginal populations. Additionally, marginal populations in South Africa typically included a greater proportion of large individuals. Recruitment intensity was greater in warm range edge populations than cold range edge populations. The size structure of the population in Namibia resembled those of central populations in South Africa. Moderate increases in densities at the absolute range limits suggest that the species is currently undergoing spread into regions associated with moderately optimal environmental conditions (ultimate range edge sites) after encountering regions associated with suboptimal environmental conditions (penultimate range edge sites).

Acoustic detectability of whales amidst underwater noise off the west coast of South Africa.

Anthropogenic underwater noise has been shown to negatively affect marine organisms globally; yet little to no noise research has been conducted in most African waters including South Africa's. This study aimed to quantitatively describe sources of underwater noise and effects of underwater noise on the acoustic detectability of Antarctic blue, fin, minke, humpback, and sperm whales off South Africa's west coast. Noise from vessel traffic (<35km to the location of recorders) dominated the soundscape below 500Hz while wind-generated noise increased with wind speed above 5ms-1 and dominated the soundscape above 500Hz. Acoustic detectability of humpback, minke and sperm whales decreased with increasing ambient noise levels whereas blue and fin whale acoustic detectability increased with the ambient noise levels. We provide baseline information on underwater noise sources and the effects of underwater noise on whale acoustic detectability off the west coast of South Africa.

Finally seen: a rare sighting of Antarctic blue whale cow–calf pair off the west coast of South Africa

Blue whales are rarely sighted off the coasts of South Africa due to their low numbers and offshore habitat preference. Visual observations to search for marine mammals were conducted onboard a platform of opportunity during the Integrated Ecosystems Programme survey in November 2019. A cow–calf pair of blue whales Balaenoptera musculus was sighted offshore Kleinzee (30°05′02.4" S, 14°24′53.2" E) at a water depth of 1670 m on the west coast of South Africa in the southern Benguela Current System. The pair was identified as Antarctic blue whales B. m. intermedia based on the size of the cow (~ 29 m), “torpedo-shaped” body of the cow, known distribution ranges and recent acoustic data showing that pygmy blue whales B. m. brevicauda do not occur in these waters. The calf was likely born in the Benguela ecosystem given its relatively small size. This is the first sighting of Antarctic blue whale cow–calf pair in South African waters post whaling, indicating that animals might still use this area as a calving or nursing ground. Improved protection of this region in the low latitudes might benefit the recovery and conservation of the species.

Morphological and molecular characterisation of Alella igillimpethu n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) parasitising the southern African endemic intertidal klipfish, Clinus superciliosus.

Lernaeopodidae Milne Edwards, 1840, is an ecological and economically important fish parasite family of copepods (Crustacea: Copepoda), consisting of 48 genera with 334 valid species. To date, approximately 17genera have been documented from both teleost and elasmobranch hosts from South African marine waters. As part of parasitological surveys targeting parasites of the endemic intertidal klipfish, Clinus superciliosus (Linnaeus) (Clinidae) along the South African coast, a species of Lernaeopodidae was discovered on the gills of this host. Alella igillimpethu n. sp. is described from Clinussuperciliosus from Langebaan marina on the west coast of South Africa, with a prevalence of 42.1% and mean intensity of 2.9 (ranging from 1-13). Morphological identification was done using light and scanning electron microscopy and the species description was generated with the aid of DEscription Language for TAxonomy (DELTA) software. The mitochondrial cytochrome c oxidase subunit 1 (COI) region, as well as partial 18S and 28S ribosomal RNA genes confirmed the classification within the family Lernaeopodidae. This is the first report of Lernaeopodidae from C.superciliosus, or in fact any member of Clinidae, as well as the first molecular characterisation of any marine lernaeopodid infecting teleost fish from South Africa. This study contributes valuable genetic and morphological data for this copepod family, as well as new host and distribution records.

Characterization of groundwater types and residence times in the Verlorenvlei catchment, South Africa to constrain recharge dynamics and hydrological resilience

• The Verlorenvlei catchment is dominated by four groundwater types that belong to three aquifer systems. • 14 C and 3 H/ 3 He residence time constraints indicate distinctly different age spectrums in the three aquifer systems. • Discrepancies between the 3 H/ 3 He and 14 C results suggests mixing along the flow paths with repeated modern recharge packages entering shallower groundwater systems. • Groundwater resilience to climate change is dependent on understanding these mixing relationships. The Verlorenvlei catchment on the west coast of South Africa is a semi−arid region that is growing progressively more reliant on groundwater due to increased variability in precipitation and increasing agricultural productivity. The groundwater systems have been put under additional stress given the recent 2015–2017 El Ninõ system that led to drought conditions along the west coast of South Africa. This increased reliance puts the natural environment and human dependence on groundwater into direct conflict. Groundwater was sampled for δ 18 O, δ 2 H, δ 13 C, 14 C, 3 H and 3 H/ 3 He ratios in addition to cation and anion concentrations from seventeen production boreholes and two springs in the catchment. Residence times were estimated using tritium and radiocarbon, and in the case of the latter, the Pearson Model has been used to correct for possible carbonate dissolution. Hydrochemistry and residence times of groundwater in the Verlorenvlei catchment have successfully been used to distinguish between the primary−porosity alluvial aquifer, the secondary−porosity Malmesbury shale aquifer (MG) and the fractured rock aquifers associated with the Table Mountain Group (TMG). Groundwater mixing has been identified within the catchment and this plays an important role in the variation in groundwater chemistry and residence time between the aquifer systems. The discrepancy between the calculated radiocarbon and 3 H/ 3 He ages in the TMG and alluvial aquifers has been evaluated using a lumped parameter model that confirms that the TMG is strongly dominated by young groundwaters. Young 3 H/ 3 He residence times calculated for groundwater in the TMG (34–57 years) and alluvial aquifers (34–47 years) implies that these systems are most susceptible to reduced groundwater recharge. Given the interconnected nature of the aquifer systems, reduced recharge rates into the TMG aquifer will decrease groundwater flow to both the alluvial and MG aquifer and this will impact the long−term sustainability of the RAMSAR listed Verlorenvlei estuarine lake and wetlands at the catchment outlet. Future residence time studies should consider using a lumped parameter model (LPM) to calculate the age distribution of groundwater in these aquifers as this would provide additional insight into the sustainability of the groundwater systems.

Social network analysis of a landscape-scale conservation initiative in South Africa

Assessment of social relations, including social network analysis, is central to understanding collaborative processes for environmental decision-making and action. The capacity of network role players to learn and adapt appropriately to uncertainty and change is a critical determinant of the resilience of socialecological systems. Poor social network structure can predispose failure. In this study, we used social network analysis to explore learning capacity and network resilience in a multi-authority conservation initiative on the West Coast of South Africa (Dassenberg Coastal Catchment Partnership). Our analysis focused on structural variables for network learning and resilience, namely connectivity, heterogeneity, and centrality. The governance network was found to be structurally connected, with the interaction between heterogeneous organisations and sectors, and centralised around a core group of actors. The network had good structural features to enable learning. However, the high level of centrality, and dependence on a small number of core actors, rendered the network potentially vulnerable to dealing with complex challenges. We recommend that core actors (1) reflect on their core functions and whether the network can absorb these functions if they were to leave and (2) tap into the knowledge potential of actors on the network periphery or invite new actors to the network when dealing with complex challenges. This may require the network to diverge into decentralised subgroups to deal with complex issues. We further suggest that the Dassenberg Coastal Catchment Partnership network incorporate social network research with qualitative monitoring into a long-term plan to monitor the movement and influence of actors as the initiative evolves. Significance: This study illustrates how social network analysis can help researchers, public-sector organisations, and donor agencies to monitor the structural features of governance networks that enable or disable learning and resilience within landscape-scale conservation initiatives. Our results illustrate how social network analysis can assist public-sector actors to reflect on their roles and whether there is redundant competency within the network to maintain its resilience.

Important marine areas for endangered African penguins before and after the crucial stage of moulting.

The population of the Endangered African penguin Spheniscus demersus has decreased by > 65% in the last 20 years. A major driver of this decrease has been the reduced availability of their principal prey, sardine Sardinops sagax and anchovy Engraulis encrasicolus. To date, conservation efforts to improve prey availability have focused on spatial management strategies to reduce resource competition with purse-seine fisheries during the breeding season. However, penguins also undergo an annual catastrophic moult when they are unable to feed for several weeks. Before moulting they must accumulate sufficient energy stores to survive this critical life-history stage. Using GPS tracking data collected between 2012 and 2019, we identify important foraging areas for pre- and post-moult African penguins at three of their major colonies in South Africa: Dassen Island and Stony Point (Western Cape) and Bird Island (Eastern Cape). The foraging ranges of pre- and post-moult adult African penguins (c. 600 km from colony) was far greater than that previously observed for breeding penguins (c. 50 km from colony) and varied considerably between sites, years and pre- and post-moult stages. Despite their more extensive range during the non-breeding season, waters within 20 and 50 km of their breeding colonies were used intensively and represent important foraging areas to pre- and post-moult penguins. Furthermore, penguins in the Western Cape travelled significantly further than those in the Eastern Cape which is likely a reflection of the poor prey availability along the west coast of South Africa. Our findings identify important marine areas for pre- and post-moult African penguins and support for the expansion of fisheries-related spatio-temporal management strategies to help conserve African penguins outside the breeding season.

E&amp;P Notes (June 2022)

E&amp;P Notes (June 2022)