Research Articles (University of Pretoria)

Permanent URI for this collectionhttp://hdl.handle.net/2263/121

This collection offers open access to the full text of research articles published by staff, students and affiliates of the University of Pretoria. These items are identical in content to their published counterparts. It is linked to the Research Information System and complements the Annual Research Report.

Access to the full text of UP theses and dissertations is available at UP Electronic Theses and Dissertations.

Information and guidelines for authors/ submitters available at http://www.ais.up.ac.za/openup/index.htm.

For inquiries regarding this collection or items in the collection, please contact : Hendriette Jansen van Vuuren
Tel.: +27 12 420 4712

Browse

Now showing 1 - 20 of 42054

A review of the marketing approaches promoting the sale of milk from non-cattle dairy species
Tsvakirai, Chiedza Zvirurami (Springer, 2025-08-04)
Despite its rich heritage, milk from goats, sheep, camels, buffalos, and donkeys has remained a minor contributor to global dairy consumption. Recent market trends have seen this milk becoming popular, and to further develop this market, the study sought to determine how the marketing of non-cow mammalian milk can be improved. It investigated this by performing a scoping review that collates and synthesizes the currently fragmented body of knowledge on firstly, the attributes of non-cattle animal-sourced milk and the production attributes that are used to create consumer value and, secondly, the marketing tools that are used for marketing the milk. The study found that positive perceptions about the nutraceutical benefits and production characteristics were key drivers of demand for non-cow mammalian milk. This was aided by sensory, cultural, and social attributes, on which consumers also held negative opinions. It further identified food labelling as the leading marketing tool used for market penetration, supported by processing, packaging and blending. The study identified under-exploited marketing opportunities that could be realised by addressing consumers’ negative perceptions, leveraging product strengths and taking advantage of emerging trends in consumer behaviour. By consolidating current knowledge and identifying marketing gaps, this research advances the discourse on non-cow animal-sourced dairy markets, underscoring the need for tailored, innovative marketing approaches.
Chemical analyses and geographical origins of residential attic dust in central South Africa
Van der Westhuizen, Deidré; Welman‑Purchase, Megan; Wichmann, Janine; Von Eschwege, Karel G. (Springer, 2025-04-10)
Particulate matter (PM) is a widely used air pollution proxy indicator. Substantial supporting evidence links exposure to PM with adverse health effects. This study compares long-term accumulated particulate matter's chemical and morphological properties and possible sources from various locations in Bloemfontein, Kimberley, and the Vanderbijlpark residential areas. As the first study of this kind in South Africa, dust samples were collected from the attics of houses built over fifty years ago. Potential area PM sources located far away were identified by analyzing every tenth year from 1972 to 2022, representing five decades of backward Long-Range Transport (LRT) clusters, for air masses that passed the sampling sites. Several PM sources were determined by combining LRT geographic origin studies and chemical analyses of collected samples. Elemental compositions of samples were determined by the use of scanning electron microscopy, and electron dispersive spectroscopy. Mineral content was determined by X-ray fluorescence, X-ray diffraction, and electron probe microscopy techniques, revealing airborne sources that moved significantly due to climate change, over the 5-decade period. Potential area PM sources located far away included various South African provinces, neighboring states to the north, and the Atlantic and Indian Oceans west and east of South Africa. Elemental composition included: Al, Ag, C, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, O, S, Si, Ti, and Zn. Mineral composition included SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5, SO3, Cr2O3 and NiO. The most prominent minerals found were quarts and plagioclase. While considering relevant mining activities, combining methods allowed a successful study of change in source distribution associated with climate change.
Improving stakeholder collaboration for sustainable agricultural mechanisation in rice production : a case study from Asutsuare, Ghana
Dorvlo, Selorm Yaotse; Baffoe, Gideon; Jew, Eleanor K.K.; Mkandawire, Elizabeth; Dougill, Andrew J. (Springer, 2025-08-22)
Sustainable agricultural mechanisation can help to achieve sustainable agricultural production using locally appropriate technology. It involves using machinery to remove the drudgery of farming practices while ensuring the environmental, socio-cultural and economic feasibility of the machinery used. In rice production, mechanisation can improve productivity, reduce methane emissions from fields, and remove low-skilled, physically-intensive, and monotonous labour requirements. It is important to recognise the challenges arising from the complex roles of the stakeholders involved in incorporating machinery into agricultural practices. There has been limited research on how these stakeholders interact in smallholder agricultural mechanization in Africa. To determine the modalities of the interactions between stakeholders and to propose a practical collaboration structure, this study evaluates the roles of various stakeholders involved in the rice production process in Asutsuare, a rice-producing region in Ghana. Stakeholders included smallholder farmers, policymakers, machinery sales agents, manufacturers, and agricultural extension agents. Using the pairwise ranking technique, the study found that smallholder farmers were the most influential stakeholders regarding mechanising rice production. However, focus group discussions and key informant interviews revealed their feelings of neglect, stemming from a lack of support and resources from other stakeholders. The study proposes establishing a multistakeholder platform supported by transactional communication models to improve collaboration and machinery utilization among smallholder rice farmers. This approach will harness the expertise of operators, extension agents, and farmers, while incorporating resources from sales agents and policymakers. Additionally, training Agricultural Mechanisation Extension agents in machinery skills is recommended to enhance their effectiveness. These strategies can be adapted for other smallholder farming communities as well. ARTICLE HIGHLIGHTS • Stakeholder collaboration is crucial for sustainable agricultural development. • The smallholder farmer is an influential and important stakeholder in smallholder rice production mechanization. • Implementing a multi-stakeholder platform and transactional communication models among stakeholders is an effective strategy to improve machinery utilization for small-scale rice farmers in Ghana. • Capacity building for stakeholders is essential to maintain an engaging platform for stakeholders, enabling them to participate in and benefit from the mechanization process.
'We should not sit in judgement on a difficult social and political problem six thousand miles away.' Dwight D. Eisenhower and apartheid South Africa
Michel, Eddie (Routledge, 2025-09-01)
My article explores how geostrategic and economic factors dictated the nature of the bilateral relationship between Washington and Pretoria during the Presidency of Dwight D. Eisenhower. In the context of the early Cold War, the vehement anti-communism of the National Party government combined with the vast mineral wealth of the apartheid state led to friendly relations with the practitioners of apartheid. The growth in trade and investment ties further tightened the bond between the two nations. While the Eisenhower administration occasionally offered a mild critique of South African racial policy, the White House sought no tangible disassociation from Pretoria even in the aftermath of the shootings at Sharpeville.
The Internet of Battle Things : a survey on communication challenges and recent solutions
Kufakunesu, Rachel; Myburgh, Hermanus Carel; De Freitas, Allan (Springer, 2025-01)
The use of Internet of Things (IoT) technology in military settings has introduced the notion of “Internet of Battle Things” (IoBT), transforming modern warfare by interconnecting various equipment and systems essential for battlefield operations. This connectivity facilitates real-time communication, data sharing, and collaboration among military assets, enhancing situational awareness, decision-making processes, and overall operational effectiveness. The domain for IoBT encompasses a broad range of military assets, from drones and ground vehicles to soldier-worn wearables, sensors, and munitions. These assets are capable of collecting and transmitting critical information from the battlefield, including location data, status updates, environmental conditions, and the movements of adversaries. IoBT networks depend on robust communication networks, secure data transmission protocols, advanced data analytics for processing vast datasets, and seamless integration with command-and-control infrastructures. However, IoBT devices and systems function in dynamic and challenging battlefield conditions which present unique communication challenges. This study aims to review research efforts that provide current state-of-the-art solutions, their limitations, and emerging technologies. We classify these challenges into interoperability, power and energy management, security, and network resilience, while also discussing future research directions to improve communication in IoBT networks.
Participation and utilisation levels of smallholder farmers agricultural credit guarantee scheme in Shinyanga and Iringa Regions, Tanzania
Sanka, Marco Bura; Makhura, Moraka Nakedi (Springer, 2025-07-19)
Agricultural credit is a key instrument in improving smallholder farmers’ agricultural production. However, in Tanzania, access to agricultural credit is a significant challenge due to the higher transaction costs of lending to smallholder farmers. The Smallholder Farmers Agricultural Credit Guarantee Scheme (SCGS) was introduced in 2018 to enhance access to credit. The study employed a double hurdle model and a Heckman two-step selection model on farm-level survey data of 500 smallholder rice farmers to estimate determinants of participation and levels of credit utilisation. The results revealed that ten variables significantly influenced participation in the SCGS, six variables determined the levels of credit utilisation and four variables had a joint influence on both participation and credit utilisation levels. Specifically, education level, household size, SCGS awareness, land ownership, rice farm size, extension services, frequency of extension contacts and membership in farm-based groups positively explain participation in the SCGS. Similarly, age, education level, household size, rice farm size, frequency of extension contacts and loan repayment period positively determined credit utilisation levels. Moreover, education level, household size, rice farm size and frequency of extension contacts jointly influenced participation and credit utilisation levels. However, off-farm income and savings from the previous cropping season negatively determined participation. These results offer valuable insights for policymakers on factors driving participation in the SCGS and credit utilisation levels, thereby supporting the design of effective strategies to enhance smallholder farmers’ participation in the SCGS and credit utilisation levels.
Staying alive : individual behavioral variation influences survival, but not reproductive success, in female group-living ground squirrels
Warrington, Miyako H.; Van der Marel, Annemarie; Sojka, Jennifer; Shofstall, Krista J.; Waterman, Jane M. (Wiley, 2025-07)
Animals living in harsh or unpredictable environments adopt adaptive strategies to improve their fitness, with behavioral variation playing a key role in shaping individual outcomes. We examined whether between-individual variation in behavioral traits (personality) was associated with reproductive success and survival in female Cape ground squirrels (Xerus inauris). Using a 10-year dataset (2011–2021), we quantified behavioral expressions of the animal's response to trapping and handling (trap response, as a proxy for docility), trapping rate (trappability, for boldness) and the number of different trapping locations an animal was trapped at (trap diversity, for exploration) and examined their associations with (1) annual reproductive success, (2) lifetime reproductive success, (3) annual survival, and (4) on-site persistence (a proxy for lifespan). Response measures taken during transfer from the cage, handling by a human observer, and whether individuals ran or walked after release were moderately repeatable. Trappability was also repeatable, while trap diversity was not. Trap response and trappability were positively correlated with survival, but not reproductive success. Females that easily transferred from the trap to the handling bag (more docile) had higher annual survival, while those that ran after release had longer lifespans. Individuals trapped at a higher rate (bolder) had higher annual survival. The absence of a relationship between behavioral traits and reproductive success in females suggests that other factors, such as group dynamics, social interactions, and maternal effects, may be more influential in explaining the high reproductive skew in female reproductive success. Overall, our findings highlight the role of individual behavioral variation in shaping survival outcomes while emphasizing the need for further research into the mechanisms driving reproductive success in this species.
Multiyear Baleen endocrine profiles suggest a longer estimated gestation in southern right whales (Eubalaena australis)
Shuttleworth, Loraine; Ganswindt, Andre; Hunt, Kathleen E.; Fernandez Ajo, Alejandro; Pieterse, Estefan; Seakamela, S. Mduduzi; Schoeman, Chantel; Vermeulen, Els (Wiley, 2025-06)
Gestation length is a key reproductive parameter influencing fecundity, population growth rates, and the recovery potential of baleen whales. However, direct knowledge of the gestation length in these large mammals remains limited, primarily inferred from whaling and observational data. Over the past decade, southern right whales have experienced a decline in reproductive success, likely linked to climate-change-induced shifts in foraging conditions. Understanding the population-level consequences of these changes requires detailed longitudinal reproductive data. This study analyzes multiyear steroid hormone profiles in the baleen of adult female southern right whales stranded along the South African coast. Results show an extended hormonal pattern characterized by two peaks in progestogens between 20 and 25 months—suggesting putative pregnancies lasting substantially longer than previous estimates. Sharp estrogen peaks during periods of elevated progestogen phases may indicate hormonal regulation of myometrial contractions at birth. A positive correlation between progestogens and glucocorticoids suggests a role for glucocorticoids in pregnancy maintenance, while androgens provide limited insight into female reproduction in this species. These findings imply a longer-than-expected gestation period for southern right whales and potentially across the balaenid family. This has important implications for understanding the timing and location of conception, relevant for conservation management strategies. Multipopulation studies alongside individual sighting histories are recommended to refine our understanding of southern right whale reproduction further.
Monthly and diel acoustic occurrence of four Baleen whale species in South African waters
Shabangu, Fannie Welcome; Hlati, Kuhle; Van den Berg, Marcel A.; Lamont, Tarron; Kirkman, Stephen P. (Wiley, 2025-08)
Understanding of the spatio-temporal occurrence of cetaceans post the whaling era is essential for protecting and improving management strategies of these marine mammals. To determine the monthly and diel acoustic occurrence of four baleen whale species relative to environmental conditions off the west coast of South Africa, we collected passive acoustic monitoring data within Child's Bank marine protected area in January and May through October 2024 at various water depths. Burst tonal calls of the southern African Bryde's whale offshore population were detected in January and May through July with the highest occurrence in January. Humpback whale songs and southern right whale gunshot sounds were detected from May through October with high occurrence in September and with smaller modes in other months. Antarctic minke whale bioduck calls were also found in June through October, showing high occurrence in August through October. Calls from an unknown source with similar characteristics to Antarctic minke whale bioduck calls were present in May, July, and August with the highest occurrence in August. Diel acoustic occurrence of Bryde's, southern right, Antarctic minke, and minke-like whale calls indicated that these animals vocalised more during the day while humpback whales were more vocally active at night. Sea surface height and sea surface temperature, either separately or in combination, were the most important predictors of whale acoustic occurrence, highlighting the influence of environmental conditions on the distribution, habitat selection, and ecology of these whales. Overall, this study advances our understanding of the movement, occurrence, and behavioural patterns of several baleen whales relative to environmental conditions. It also provides the first description of the southern African Bryde's whale offshore population's call characteristics, which will be useful at guiding future studies to acoustically differentiate between it and the inshore population.
Interspecies haptic sociality : an observation of grooming between two mongoose species
Smith, Kyle; Hepplewhite, Malcolm; San, Emmanuel Do Linh; Somers, Michael J. (Wiley, 2025-06)
Meerkats (Suricata suricatta) and yellow mongooses (Cynictis penicillata) share many behavioural characteristics and are known to, on rare occasions, live in close association through displayed cooperative vigilance and shared burrow use. Here, we describe the first visual observation of tactile social behaviour through grooming between a meerkat and a yellow mongoose in the Rietvlei Nature Reserve, South Africa. We hypothesise that the close relationship between the two species in the reserve may be a response to a combination of phylogenetic ties, shared behavioural traits, and the population collapse of meerkats in the reserve that exposed a vacant social niche. This observation of interspecific sociality further extends our knowledge of cooperation and group augmentation among meerkats, yellow mongooses and carnivores in general.
The evolution of athlete branding : a bibliometric analysis
Golmohammadi, Hamed; Hasaan, Ali; Berndt, Adele; Fişne, Mücahit (Sage, 2025)
Athlete branding has become an increasingly important topic in sports management and marketing, particularly in the digital era. This study provides a comprehensive bibliometric analysis of athlete branding research from 2000 to 2024 to map the field's key developments and trends. Using performance analysis and science mapping, this study examined related scholarly publications and identified prolific authors, influential journals, and dominant themes. This study highlights the evolving nature of athlete branding and offers future research directions at the intersection of sports, business, and digital media. Specific research opportunities linked to these themes have been identified in the literature, and this study also suggests location, contextual, and methodological research. This review offers a deeper understanding of actionable research opportunities for both scholars and practitioners in the field.
Dietary plasticity of African clawless otters (Aonyx capensis) : an assessment of seasonal variation in prey availability
Burger, Marli; Ganswindt, Andre; Majelantle, Tshepiso L.; Scheun, Juan; Webster, Andrea B. (Wiley, 2025-07)
African clawless otters (Aonyx capensis) are opportunistic feeders with a broad dietary niche. Variation in their diet can be influenced by environmental and anthropogenic factors, which can affect seasonal and longitudinal prey availability. Flexibility in the diet allows African clawless otters to adapt to these changes and exploit novel prey items when available. Seasonal examination of otter spraints from three different locations across South Africa demonstrates that African clawless otters are able to shift from their preferred crab-based diet to a fish- or insect-based diet in response to environmental and anthropogenic drivers. Here we provide direct evidence of African clawless otters in terrestrial environments shifting to an insect-dominated diet when this resource is available. The dietary plasticity and response of this species to the shifts in available prey items may be an important factor for future consideration in conservation management of the species.
Despite potential risks African elephants do not always avoid mountaineering
Teixeira, Justine M.; Van der Westhuizen, Rickert; Shrader, A.M. (Adrian) (Wiley, 2025-07)
As herbivores forage, they move across a wide range of topographical features. Yet, they tend to avoid terrain such as steep slopes where energetic costs of movement are high and there is a greater risk of falls and tumbles. Recent studies suggest that African elephants (Loxodonta africana) avoid steep slopes (e.g., > 15°). However, in reserves with undulating topography, elephants may have to use steep slopes to obtain food, especially when availability is limited in more gradual areas. To explore this, we investigated slope use by elephants in the Ithala Game Reserve, South Africa, where the topography varies greatly and ranges between 400 to 1400 masl. Using 8.5 years of positional data, we examined how slope use varied between herd types (14 breeding herds and 13 males), habitat type and season (wet vs. dry). Elephants were found primarily on slopes < 30° (i.e., 95% of the locations), while 67% of the locations were on slopes < 15°, and 52% on slopes < 10°. Breeding herds used steeper slopes (mean = 12.6° ± 0.08 SE) than bulls (mean = 12.0° ± 0.8 SE). In addition, habitat influenced slope use, with the steepest slopes used in woodlands and the most gradual used in built-up areas and grasslands. However, these slope use differences were very small (i.e., 0.6° to 9.7°) and thus unlikely to be biologically meaningful. Rather, the ability to detect these slight differences was likely an artefact of our large sample size (N = 23,837 locations). Moreover, slope use did not vary between the wet and dry seasons. Nevertheless, 5% of all the elephant locations occurred on very steep slopes (i.e., > 30°) and 33% were on slopes > 15°, indicating that although they may prefer flat terrain, when required, elephants will mountaineer.
Stretching out : leopard home-range expansion in response to suppressed population density in a recovering post-war landscape
Briers-Louw, Willem D.; Kendon, Tamar A.; Hayes, Andres; Gaynor, David; Naude, Vincent (Wiley, 2025-10)
Large carnivores have profound regulatory effects on ecosystems and provide substantial socio‐economic benefits. However, mounting anthropogenic pressures are driving their global decline, threatening many species with extinction. Leopards, in particular, face challenges due to their wide‐ranging behavior, which exposes them to conflict with people and bycatch snaring, highlighting the importance of understanding their spatial ecology to develop more effective conservation strategies. This study aimed to estimate the home‐range size of female leopards (n = 4) within the Zambezi Delta, a unique mesic landscape undergoing broad‐scale ecological recovery in central Mozambique. Home‐range sizes ranged from 46 to 365 km2, falling within the range of global estimates. Surprisingly, these home‐range sizes, along with additional parameter estimates such as daily distance moved and home‐range overlap, were most comparable with those reported in arid environments. With female leopards appearing to occupy larger areas than theoretically required based on energetic needs, it is plausible that their spatial ecology is likely influenced by low population density. As the population recovers, we anticipate a re‐structuring of socio‐spatial dynamics driven by dispersal‐regulated processes, with females likely contracting their home‐range and partitioning them to their philopatric daughters. This study provides the first robust estimation of leopard home ranges in Mozambique and provides critical insights into the spatial ecology of leopards in a post‐war landscape. We recommend long‐term monitoring to track changes in population demographics and socio‐spatial dynamics as restoration efforts continue across central Mozambique.
Threatened endemic arthropods and vertebrates partition their diets with non-native ants in an isolated island ecosystem
Tercel, Maximillian P.T.G.; Cuff, Jordan P.; Symondson, William O.C.; Moorhouse-Gann, Rosemary J.; Bishop, Tom Rhys; Cole, Nik C.; Jolin, Eric; Govier, Bethan; Chambon, Johannes; Mootoocurpen, Rouben; Goder, Martine; Vaughan, Ian P. (Wiley, 2025-07)
The success of non-native species depends on their ability to find food, which may ultimately lead to competition with native species and contribute to biodiversity loss in invaded ecosystems. Understanding which food resources are consumed is therefore crucial for evaluating how non-native species mechanistically fit into native biological communities. Non-native species may be predators or competitors of native species or may be consumed by native species as a novel source of nutrition, for example, and this can occur between both closely and distantly related species. Studies examining competitive interactions between non-native species and distantly related native taxa are relatively rare, largely because it is difficult to compare their diets using traditional methods. However, dietary DNA metabarcoding overcomes these limitations by enabling the construction of highly detailed food webs. Here, we use dietary DNA metabarcoding between two generalist native consumers—a reptile (Telfair's skink) and a Scolopendra centipede (Serpent Island centipede)—and the hyperabundant non-native ant community to test which consumer groups prey upon one another and partition food resources. To determine how non-native ants fit into a native community, we calculated dietary composition, niche overlap, and dietary diversity of ants, centipedes, and skinks on Round Island, a small 2.19-km2 oceanic island located 22.5 km north-east of Mauritius. We observed distinct partitioning of food resources among the three consumer groups—skinks, centipedes, and ants—and found that the level of predation between these groups varied. Skinks and centipedes frequently consumed non-native ants, which may represent an important nutritional resource for both native consumers. Dietary differences persisted through seasons despite large shifts in the availability of food and concomitant diet composition for all three consumers. We conclude that non-native ants fit into the biological community of Round Island as both prey for native consumers and extreme omnivorous generalists, but not necessarily at the expense of the native consumers because it is unlikely the consumers are competing for food resources. Our results suggest that abundant non-native generalists, which are highly invasive in much of their introduced range, can infiltrate native food webs without exerting strong competitive forces on other common native generalist species.
Creating the vision of rapid, repeatable, reactive data workflows for policy on biodiversity
Groom, Quentin; Abraham, Laura; Adriaens, Tim; Breugelmans, Lissa; Clarke, David A.; Di Musciano, Michele; Dove, Shawn; Estupinan-Suarez, Lina M.; Faulkner, Katelyn T.; Fernandez, Miguel; Hendrickx, Louise A.; Hui, Cang; Joly, Alexis; Kumschick, Sabrina; Langeraert, Ward; Martini, Matilde; Miller, Joe; Oldoni, Damiano; Pereira, Henrique; Preda, Cristina; Robertson, Tim; Rocchini, Duccio; Rodrigues, Andrew; Ryckewaert, Maxime; Seebens, Hanno; Sica, Yanina V.; Teixeira, Heliana; Trekels, Maarten; Vandaele, Toon; Wilson, John R.U.; Zengeya, Tsungai; Desmet, Peter (Wiley, 2025-07)
1. Effective biodiversity management and policymaking requires timely access to accurate and reliable scientific data on biodiversity status, trends and threats. However, current biodiversity monitoring processes are often time-consuming, complex and irreproducible. Moreover, the quality and types of biodiversity data are diverse, which challenges their integration and impedes effective monitoring. A major step to overcome such challenges would be the availability of standardized species occurrence data. However, challenges arise in aggregating and integrating these heterogeneous data with environmental and landscape data. 2. By creating standardized biodiversity data cubes and automated workflows for post-processing, we envision that (1) information from complex datasets will be available in a known format to efficiently communicate biodiversity variables to policymakers; (2) the adoption of repeatable Open Data workflows will make biodiversity data more accessible, efficient and cost-effective; and (3) cloud computing will make it easier to analyse large datasets, benefit from a broader range of models, share resources and work together on biodiversity projects. 3. This revolution in biodiversity monitoring will rely on community collaboration. By bridging the gap between policymakers' needs, bioinformation specialists' skills and data collectors' motivations, biodiversity monitoring can become a more inclusive and community-driven effort. As such, we advocate for the development of tools and workflows in close consultation with stakeholders to enhance the impact and use of biodiversity information. 4. Practical implication. The proposed approach faces challenges in maintaining software, data standards and addressing biodiversity data complexity. However, leveraging existing infrastructures like GBIF and Copernicus, and building on the knowledge from GEO and GEO BON offers a feasible path.
Assessing Gonipterus defoliation levels using multispectral unmanned aerial vehicle (UAV) data in Eucalyptus plantations
Nzuza, Phumlani; Schröder, Michelle L.; Heim, Rene J.; Daniels, Louis; Slippers, Bernard; Hurley, Brett Phillip; Germishuizen, IIaria; Sivparsad, Benice; Roux, Jolanda; Maes, Wouter H. (Elsevier, 2025-12)
Invasive insect pest Gonipterus sp. n. 2 (Coleoptera: Curculionidae) threatens Eucalyptus species, causing defoliation and yield loss through adult and larval feeding. Early detection is important for early intervention to prevent pest outbreaks. As conventional insect pest monitoring methods are time-consuming and spatially restrictive, this study assessed the potential of UAV monitoring. Multispectral imagery was obtained with Unmanned Aerial Vehicles (UAVs) across six different stands of young Eucalyptus dunnii with varying levels of Gonipterus sp. n. 2 infestations. Some stands were revisited, a total of 9 datasets were covered. Reference damage levels were obtained through visual assessments of (n = 89–100) trees at each site. Across sites, a decrease in canopy reflectance in both the visual and the near-infrared domains with increasing damage levels was consistently observed. Several vegetation indices showed consistent patterns, but none showed site independence. XGBoost, Support Vector Machine and Random Forest (RF) were used to predict damage levels using five input spectral data types. XGBoost performed best, closely followed by RF. Both models consistently selected very similar features. The best-performing models included reflectance, vegetation indices and grey-level co-occurrence matrix data. When data from 10 different wavelengths were used, the highest classification accuracy was 92 % across all sites in classifying defoliation levels. With a classical 5-band multispectral camera, accuracy was 88 %, but distinguishing medium damage from low remained challenging. However, the method was less reliable when trained and validated on separate fields. This study highlights the potential of multi-site datasets in increasing the model's generalization, using UAV based multispectral imagery to assess Gonipterus sp. n. 2 damage and demonstrating reliable upscaling from individual tree assessments to stand scale. However, it also recognises the difficulty of generating a robust model that performs well on untrained sites. HIGHLIGHTS • Canopy damage from Gonipterus sp. n. 2 was assessed across stands using UAV imagery, capturing defoliation, chlorophyll reduction. • The 5-band imagery perfomed comparable to the 10-band but was less effective at detecting subtle low vs no damage defoliation. • Similar pattern was observed across sites but absolute reflectance and vegetation indices are site specific.
The preference for energetic resources is positively associated with predatory activity in ants
Wilker, Icaro; Bishop, Tom Rhys; Lasmar, Chaim J.; Veiga, Dara; Souza, Leticia G.; Queiroz, Antonio C.M.; Feitosa, Rodrigo M.; Neundorf, Ana C.A.; Martins, Mila F.O.; Alves, Guilherme P.; Fontenele, Luane K.; Costa, Marilia M.S.; Ribas, Carla R. (Wiley, 2025-10)
1. Land use changes can alter resource availability and microclimate variables in tropical ecosystems, generally altering community structure by decreasing species richness and changing its composition. These changes affect foraging activity, nutrient preferences and consequently ecosystem functions. 2. Our aim was to assess how foraging activity and nutrient preference are influenced by changes in land use and microclimate. 3. We sampled ants (Formicidae) at 32 sites undergoing conversion from natural habitats to coffee systems in two Neotropical biomes: the Atlantic rainforest and the Cerrado. We assessed nutrient preference (amino acids, carbohydrates, lipids and sodium) and predation using mealworm larvae, while also measuring temperature and humidity. 4. We found the same ants foraged for different resources, likely because generalist species can perform these activities on the ground. Furthermore, foraging for energetic resources (carbohydrates and lipids) positively correlated with foraging for larvae. This indicates that the limitation of energetic resources can contribute to an increase in foraging and predatory activity. Moreover, ant preference for amino acids decreases with increasing temperature, indicating that ants prefer to consume energetic resources to support metabolic processes. 5. In conclusion, foraging is primarily carried out by generalist species. In addition, the preference for energetic nutrients, driven by energetic limitations, is linked to predatory activity. Moreover, ant species richness increases foraging for larvae, while rising temperatures decrease the preference for amino acids. Thus, conserving species richness and mitigating temperature increases may enhance larval foraging and support the insect predation function in Neotropical habitats.
Cervical cancer awareness among women recently diagnosed with cervical cancer in South Africa and Zimbabwe
Govender, Sudarshan; Phillips, Tamsin K.; Walter, Fiona M.; Day, Sarah; Guzha, Bothwell; Scott, Suzanne E.; Chirenje, Zvavahera M.; Ataguba, John Ele-Ojo; Mbatani, Nomonde; Fakie, Nazia; Moodley, Jennifer (ecancer , United Kingdom, 2025-10)
Incidence and mortality rates of cervical cancer remain high in Southern Africa (SA). We explored awareness of cervical cancer symptoms and risk factors, as well as risk lay beliefs among women recently diagnosed with cervical cancer from SA and Zimbabwe. Patients were asked to complete a locally validated questionnaire with unprompted, open-ended questions to assess awareness of cervical cancer symptoms and risk factors. Among 501 women (SA 285, Zimbabwe 216), 46% (229) were able to recall one or more symptoms (SA 24%, Zimbabwe 76%) and 19% (93) were able to recall one or more risk factors of cervical cancer (SA 27%, Zimbabwe 73%). In SA, factors associated with increased symptom awareness included higher education level (completion of secondary education compared to not completing secondary education; adjusted odds ratios (aOR) 2.74, 95% confidence interval (CI) 1.17–6.43) as well as living in urban and peri-urban areas compared to living in rural areas (Urban: aOR 2.98, 95% CI 1.35–6.80; Peri-urban: aOR 3.28, 95% CI 1.13–9.35). Having a self-reported history of a chronic condition was associated with lower risk factor awareness compared to not having a self-reported chronic condition (aOR 0.07, 95% CI 0.00–0.42). In Zimbabwe, those who self-reported living with HIV were more likely to know one or more risk factors compared to those without HIV (aOR 2.69, 95% CI 1.31–5.67). Overall, 90 (18%) women mentioned at least one lay belief about risk factors for cervical cancer, with the most reported being inserting herbs, creams or objects into the vagina (9%, n = 43). The low levels of cervical cancer awareness in two Southern African countries highlight the urgent need to improve cervical cancer awareness, as low levels of awareness can impact timely cancer diagnosis and limit the uptake of cervical cancer prevention programs.
Conserving carbon stocks under climate change : importance of trees outside forests in agricultural landscapes of Mongala Province, Democratic Republic of Congo
Azenge, Jean Pierre; Zon, Aboubacar-Oumar; Diesse, Hermane; Meniko, Jean Pierre Pitchou; Ebuy, Jerome; Kassi, Justin N'Dja; Chirwa, Paxie W. (MDPI, 2025-06)
This study aimed to evaluate the role of trees outside forests on agricultural land (TOF-AL) in preserving the initial aboveground biomass (AGB) of forests within the agricultural landscape of Mongala province in the Democratic Republic of Congo. In 2024, tree inventories were conducted over four months in the forests and agricultural lands of Mongala province to analyse AGB. The effects of artisanal logging and charcoal production activities on the AGB conservation rate were considered. This study indicates that 78.3% of the trees encountered in agricultural lands were large-diameter trees (diameter at breast height (DBH) ≥ 60 cm). In forest areas, large-diameter trees accounted for 55.9% of tree density. The average AGBs are 66.8 Mg ha−1 for TOF-AL and 373.5 Mg ha−1 for forest trees. The AGB of TOF-AL accounts for 17.9% of the AGB of the total forest trees. The AGB conservation rates vary by region, with Lisala having the highest at 22.1%, Bumba the lowest at 11.2%, and Bongandanga at 20.5%. Artisanal logging and charcoal production reduce the AGB conservation rate of TOF-AL. The AGB conservation rate is positively correlated with the distances to major cities. These results prove that conserving trees in agricultural landscapes can reduce the AGB losses associated with slash-and-burn agriculture and contribute to mitigating climate change effects.

Browse

Recent Submissions