Research Articles (Plant Production and Soil Science)
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Item Patterns of mature woody plant species encroachment on vegetation structure, density, and diversity of the understory layer across the Marikana Thornveld(Frontiers Media, 2025-05) Mangwane, Mziwanda; Madakadze, Ignacio Casper; Tjelele, Tlou Julius; Ramoelo, Abel; u14387027@tuks.co.zaINTRODUCTION : Bush encroachment has a negative impact on the vegetation structure, ecosystem functions, and services of savanna rangelands. Woody plant encroachment creates an imbalance in the grass-to-tree ratio, leading to a decline in ecosystem services, including grazing capacity and soil nutrients. METHODS : This study aimed to evaluate the vegetation structure, diversity, and relationships of tree species across four different growth stages in the Marikana Thornveld. Three sites were identified at the Roodelpaat experimental farm, where six 1-hectare plots were established. In each plot, nine 10 m × 10 m subplots were set up to identify mature woody plants, shrubs, and saplings. Seedlings were identified within three 1.69 m² quadrats nested within each subplot. RESULTS AND DISCUSSION : The study identified a total of 9,028 individual woody plants, including 158 seedling species, 161 saplings, 159 shrubs, and 154 mature woody plant species. The regression line plotted seedling density against the densities of mature trees, shrubs, and saplings, with b values significantly less than 1, indicating a negative impact of mature trees, shrubs, and saplings on the seedling layer. Seedling abundance displayed a non-linear relationship with mature trees, indicating a 4.75% representation of seedling abundance within the mature tree layer. Woody seedling species exhibited the highest abundance across four growth stages. Overall, across all woody plant species at different growth stages, there was a general decline in the woody density class, resulting in a J-shaped curve pattern. Seedlings and mature trees exhibited the highest diameter at breast height (dbh) proportions among individual woody plants from the first to the third DBH size classes, followed by a decline. CONCLUSION : Generally, these results highlight a weak relationship between mature woody plant species and the understory layer, including shrubs, saplings, and seedlings. Consequently, mature woody plants cannot predict the establishment of understory woody plants or the recruitment of seedlings as a cause of bush encroachment.Item Research progress on climate change adaptation strategies to control invasive crop pest in sub-Saharan Africa : a bibliometric and systematic review(Frontiers Media, 2025-02) Assede, Emeline Sessi Pelagie; Othoo, Calvince Ouko; Ly, Ahmadou; Bayisa, Gobena; Tarkegn, Temesgen Gashaw; Zohoun, Megnisse; N'goran, Anje-JokebedThis bibliometric and systematic review assesses research progress and climate change adaptation strategies to control invasive crop pests in sub-Saharan Africa. Scientific publications on crop pest management in sub-Saharan Africa in a context of climate change adaptation were extracted from papers published between 1991 and 2024. A literature search was conducted on Scopus, dimension, and google scholar, followed by screening and data extraction in compliance with ROSES standards. Findings indicated that pests such as armyworms, fruit flies and coffee berry borer cause huge losses. Communities are adopting integrated pest management, water harvesting, drip irrigation, resistant varieties, and improving production efficiency. Agro-ecological practices reduce pest invasions while preserving the environment. Meanwhile, chemical insecticide use remains an emergency solution as its effects on pest control would be more efficient. However, promising approaches emerge around biocontrol, agroforestry integrating pest management, and gender-tailored strategies. Nevertheless, regional disparities persist in scientific output. In conclusion, while invasive pests represent a major plant health crisis in sub-Saharan Africa, this review highlights innovative adaptation strategies. Their development will require coordinated mobilization to catalyze the sustainable agro-ecological transition that sub-Saharan Africa needs to address these multidimensional challenges. Future research should assess farmer’s perception on the effectiveness of the existing pest management practices for invasive crop pests.Item Comparative analysis of five African traditional multipurpose crops using a food systems approach(Taylor and Francis, 2025) Munialo, Sussy; Madzorera, Isabel; Lartey, Anna; Abdallah Noor, Ramadhani; Thiam, Aboubacry; Covic, Namukolo; Amos, Laar; Adelheid, Onyango; Baye, Kaleab; Nikiema, Laetitia Ouedraogo; Wafaie, Fawzi; Sibanda, Lindiwe Majele; sussy.munialo@up.ac.zaDiversifying food systems with traditional multi-purpose crops like sorghum, cassava, and amaranth is key to improving food security and nutrition. However, studies focusing on a variety of nutrient-dense crops, addressing research, policy, and practice, are missing. Most research focuses on cereals like sorghum, overlooking other crops such as vegetables, root crops, legumes, and nuts, limiting nutrient diversity in food system. A review of five traditional crops—sorghum, amaranth, cassava, cowpea, and cashew nuts—assessed research, policy, and practice, aiming to enhance food systems. The review found that existing initiatives on traditional crops are mainly production-focused and region-specific, with gaps in processing, value addition, marketing, nutrition, consumption, and transport. Limited policies and stakeholder involvement has hindered commercialization. Key recommendations should be implemented across research, practice, and policy along the food systems. Research actions include improving taxonomic classification, developing modern breeding programs, researching yield gaps, and enhancing understanding of transport and logistics. Practical strategies involve improving field management through training, integrating informal and formal seed systems, and promoting commercial use. Policies should address all food system aspects including processing, consumption, marketing, and transportation. Increased stakeholder engagement across the value chain is essential for unlocking the potential of traditional crops.Item Drivers of woody dominance across global drylands(American Association for the Advancement of Science, 2024-10-11) Biancari, Lucio; Aguiar, Martín R.; Eldridge, David J.; Oñatibia, Gastón R.; Le Bagousse-Pinguet, Yoann; Saiz, Hugo; Gross, Nicolas; Austin, Amy T.; Ochoa, Victoria; Gozalo, Beatriz; Asensio, Sergio; Guirado, Emilio; Valencia, Enrique; Berdugo, Miguel; Plaza, César; Martínez-Valderrama, Jaime; Mendoza, Betty J.; García-Gómez, Miguel; Abedi, Mehdi; Ahumada, Rodrigo J.; Alcántara, Julio M.; Amghar, Fateh; Anadón, José D.; Aramayo, Valeria; Arredondo, Tulio; Bader, Maaike Y.; Bahalkeh, Khadijeh; Salem, Farah Ben; Blaum, Niels; Boldgiv, Bazartseren; Bowker, Matthew; Branquinho, Cristina; Bu, Chongfeng; Byambatsogt, Batbold; Calvo, Dianela A.; Monroy, Andrea P. Castillo; Castro, Helena; Castro-Quezada, Patricio; Chibani, Roukaya; Conceição, Abel A.; Currier, Courtney M.; Donoso, David A.; Dougill, Andrew; Ejtehadi, Hamid; Espinosa, Carlos I.; Fajardo, Alex; Farzam, Mohammad; Ferrante, Daniela; Fraser, Lauchlan H.; Gaitán, Juan J.; Gherardi, Laureano A.; Gusmán-Montalván, Elizabeth; Hernández-Hernández, Rosa M.; Hölzel, Norbert; Huber-Sannwald, Elisabeth; Hughes, Frederic M.; Jadán, Oswaldo; Jeltsch, Florian; Jentsch, Anke; Ju, Mengchen; Kaseke, Kudzai F.; Kindermann, Liana; Köbel, Melanie; Le Roux, Peter Christiaan; Liancourt, Pierre; Linstädter, Anja; Liu, Jushan; Louw, Michelle A.; Maggs-Kölling, Gillian; Issa, Oumarou Malam; Marais, Eugene; Margerie, Pierre; Messeder, João Vitor S.; Mora, Juan P.; Moreno, Gerardo; Munson, Seth M.; Oliva, Gabriel; Pueyo, Yolanda; Quiroga, R. Emiliano; Reed, Sasha C.; Rey, Pedro J.; Rodríguez, Alexandra; Rodríguez, Laura B.; Rolo, Víctor; Ruppert, Jan C.; Sala, Osvaldo; Salah, Ayman; Stavi, Ilan; Stephens, Colton R.A.; Swemmer, Anthony M.; Teixido, Alberto L.; Thomas, Andrew D.; Throop, Heather L.; Tielbörger, Katja; Travers, Samantha K.; Van den Brink, Liesbeth; Wagner, Viktoria; Wamiti, Wanyoike; Wang, Deli; Wang, Lixin; Wolff, Peter; Yahdjian, Laura; Zaady, Eli; Maestre, Fernando T.Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in 304 plots across 25 countries to assess how climatic features, soil properties, grazing, and fire affect woody dominance in dryland rangelands. Precipitation, temperature, and grazing were key determinants of tree and shrub dominance. The effects of grazing were determined not solely by grazing pressure but also by the dominant livestock species. Interactions between soil, climate, and grazing and differences in responses to these factors between trees and shrubs were key to understanding changes in woody dominance. Our findings suggest that projected changes in climate and grazing pressure may increase woody dominance in drylands, altering their structure and functioning.Item Phytoindication and phytoremediation of water quality using the local duckweed plant Lemna aequinoctialis(Wiley, 2025-03) Munaro, Allen Takudzwa; Tsamba, Joshua; Siziba, NqobizithaEnvironmental pollution exacerbates global freshwater scarcity. In Harare, sewage pollution drives freshwater pollution, compromising its quality and security. Here, we uniquely explored the dual role of Lemna aequinoctialis as a phytoindicator and phytoremediator of freshwater quality. Using a purposive sampling strategy targeting common household freshwater abstraction sites in selected communities of Harare (Tafara and Manyame), 12 water samples and an L. aequinoctialis culture were collected from the field and incubated in the laboratory. Biochemical oxygen demand (BOD), electrical conductivity (EC), and potential hydrogen (pH) were determined by probes, while total suspended solids (TSS) and turbidity were analyzed by UV-Vis Spectrometry. Chemical oxygen demand (COD), nitrates (NOˉ₃), nitrites (NOˉ2), and orthophosphates were analyzed by colorimetric techniques. An analytical balance measured the plant fresh weights and root lengths were measured via microscopy. Akin to +raw sewage, River B (Tafara) exhibited the highest initial pollutant load; BOD (3.8 mg/L), COD (38 mg/L), TSS (96 mg/L), NOˉ₃ (0.134 mg/L), NOˉ2 (0.058 mg/L), orthophosphates (0.524 mg/L), turbidity (87 FTU), with notably reduced mean fresh biomass (2.9 g) and root length (7.3 mm) which were moderately and negatively correlated with NOˉ2 and orthophosphates, respectively. Only EC failed to improve after L. aequinoctialis incubation significantly. Despite spatial-temporal limitations, we present limited evidence suggesting a potential real-time, dual utility role that can help track, redress pollution, and suppress algal blooms enhancing public health and transcending the typical role of duckweeds. Long-term applicability of this phytotechnology requires further attention for sustainable freshwater management in resource-limited regions like Zimbabwe.Item Pathogenicity of Pythium myriotylum on Acacia crassicarpa and Acacia mangium x Acacia auriculiformis clones in Indonesia(Taylor and Francis, 2025) Tarigan, Marthin; Wingfield, Michael J.; Jami, Fahimeh; Oliveira, Leonardo S.S.; Saha, Muhammad A.; Duran, Alvaro; Pham, Nam Q.; nam.pham@fabi.up.ac.zaThe oomycete Pythium myriotylum is an important pathogen of several crops, causing wilt and damping-off during nursery propagation. The pathogen was recently reported as the causal agent of wilt and damping-off on Acacia crassicarpa plants in nurseries located in Riau, Indonesia. The aim of this study was to evaluate the relative pathogenicity of P. myriotylum on different clones of A. crassicarpa and Acacia mangium × Acacia auriculiformis hybrids. Based on the results, greater tolerance was found on the A. mangium × A. auriculiformis hybrid clones than on those of pure A. crassicarpa. The different Acacia clones also displayed different levels of tolerance of infection. Overall the results showed that screening for tolerance to infection by P. myriotylum will be important in the Acacia breeding programme and make it possible to produce sufficient nursery stock for plantation establishment.Item Coleus serracafemaensis (Lamiaceae), a New Succulent Species from Southwest Angola(Cactus and Succulent Society of America, Inc., 2024-02) Van Jaarsveld, Ernst J.; Swanepoel, Wessel; Paton, Alan; Becker, Rolf; De Cauwer, Vera; Gomez, AmandioColeus serracafemaensis, an ascending sparingly branched shrub with tuberous roots and sky-blue flowers is described here as a new species. It has a restricted range and is only known from Serra Cafema Mountain in southern Angola (within the Kaokoveld Centre of Endemism, southwestern Angola and northwestern Namibia). It grows on granite derived soil among granite boulders in a steep south facing boulder strewn kloof. Diagnostic characters for Coleus serracafemaensis include the large, tuberous rootstock, photosynthesizing stems with peeling bark, distinctly petiolate, broadly ovate to trullate leaves and its large sparingly branched panicles and accrescent sub-equally 5-lobed calyces, each lobe ending in a spine. Coleus serracafemaensis belongs to a group of species previously recognized as belonging to the genus Holostylon which includes 4 species with virgate ascending stems from a perennial base, persistent pedicels breaking near the base of the deciduous fruiting calyx, single flowered cymes and minutely lobed, almost entire style apices. A comparison of some of the more prominent morphological features to differentiate between Coleus serracafemaensis and its possible nearest relative, Coleus gracilipedicellatum, is provided. Based on IUCN Red List categories and criteria, a conservation assessment of Vulnerable (VU D2) is recommended for the new species.Item Aboveground physiological response and yield prediction of Chloris gayana and Digitaria eriantha grown in rehabilitated coal mined soils using random forest algorithm(Wiley, 2025-09) Abraha, Amanuel Bokhre; Tesfamariam, Eyob Habte; Truter, Wayne F.; Abutaleb, Khaled; Newete, Solomon W.A recent study demonstrated that a blend of amendments improved both the physical and hydraulic properties of reclaimed mine soils more effectively than standard mine treatments, suggesting further research on its impact on plant growth. Additionally, there is currently no published research that has examined the potential of the random forest (RF) algorithm for predicting the aboveground yield of Chloris gayana (Rhodes grass) and Digitaria eriantha (Smutsfinger grass) grown in reclaimed mine soils. To address this, a field trial of 36 bins consisting of nine treatments and four replications each was conducted in a randomized block design at the experimental farm of the University of Pretoria. The results showed that the dry matter yield, leaf area index, and leaf water potential were all significantly (p < 0.05) affected by the treatment. The blend of amendments increased aboveground dry matter yield by 70%–150% and leaf area index by 60%–95%. These improvements significantly enhanced productivity and, consequently, the carrying capacity of the rehabilitated land compared to the standard mine treatment of liming and fertilization. The most important wavelengths for predicting aboveground yield were located in the visible (400–700 nm) region of the electromagnetic spectrum, yielding an r2 of 0.90, mean absolute error of 0.183 t ha−1 and root mean square error of 0.255 t ha−1. These findings demonstrate that a blend of amendments can enhance the production potential of these grasses by improving soil nutrient availability. However, the longevity of these effects needs to be verified through long-term studies. The results also indicate that RF algorithm can accurately predict aboveground yield of C. gayana and D. eriantha accurately based on changes in the plant canopy spectral signature.Item Does wind affect the orientation of vegetation stripes? A copula-based mixture model for axial and circular data(Wiley, 2025-07) Mingione, Marco; Lagona, Francesco; Nagar, Priyanka; Von Holtzhausen, Francois Victor; Bekker, Andriette, 1958-; Schoombie, Janine; Le Roux, Peter ChristiaanMotivated by a case study of vegetation patterns, we introduce a mixture model with concomitant variables to examine the association between the orientation of vegetation stripes and wind direction. The proposal relies on a novel copula-based bivariate distribution for mixed axial and circular observations and provides a parsimonious and computationally tractable approach to examine the dependence of two environmental variables observed in a complex manifold. The findings suggest that dominant winds shape the orientation of vegetation stripes through a mechanism of neighboring plants providing wind shelter to downwind individuals.Item High genetic diversity and limited regional population differentiation in populations of Calonectria pseudoreteaudii from Eucalyptus plantations(American Phytopathological Society, 2025-01) Li, WenWen; Liu, Feifei; Chen, ShuaiFei; Wingfield, Michael J.; Duong, Tuan A.Calonectria pseudoreteaudii causes a serious and widespread disease known as Calonectria leaf blight in Eucalyptus plantations of southern China. Little is known regarding the population biology or reproductive biology of this pathogen in the affected areas. The aims of this study were to investigate the genetic diversity, population structure, and reproductive mode of C. pseudoreteaudii from affected Eucalyptus plantations of southern China. Ten polymorphic simple sequence repeat markers were developed for the species and were used to genotype 311 isolates from eight populations. The mating types of all isolates were identified using the MAT gene primers. The results revealed a high level of genetic diversity of the pathogen in all investigated populations. Of the 90 multilocus genotypes detected, 10 were shared between at least two populations. With the exception of one population from HuiZhou, GuangDong (7HZ), the most dominant genotype was shared in the seven remaining populations. Discriminant analysis of principal components and population differentiation analyses showed that the 7HZ population was well differentiated from the others and that there was no significant differentiation between the remaining populations. Analysis of molecular variance suggested that most molecular variation was within populations (86%). Index of association analysis was consistent with a predominantly asexual life cycle for C. pseudoreteaudii in the studied regions. Although both mating types were detected in seven of the eight populations, the MAT1-1/MAT1-2 ratios in these populations deviated significantly from the 1:1 ratio expected in a randomly mating population.Item Navigating power dynamics in food safety governance : the case of South Africa's compulsory specification for processed meat products(Institute for Social Development, University of the Western Cape, 2025-06) Mkhwanazi, Ntombizethu Simphiwe; Adelle, Camilla; Korsten, LiseThe 2017–2018 listeriosis outbreak in South Africa had a severe impact on the processed meat industry, prompting significant regulatory changes including the development of the Compulsory Specification for Processed Meat Products (VC 9100). This regulation aimed to improve food safety standards by mandating the implementation of a Hazard Analysis and Critical Control Points system across all processed meat production facilities. Drafting of the VC 9100 was initiated in 2013 following concerns that existing voluntary standards were inadequate for protecting public health. However, progress was hindered by strong resistance from industry stakeholders who argued that compliance would be financially burdensome, particularly regarding the costs and levies associated with its enforcement. The listeriosis outbreak, which resulted in over 219 deaths, dramatically shifted the regulatory landscape. The crisis brought food safety to the forefront of the national agenda, compelling the government to accelerate the development and implementation of VC 9100. Despite the urgency, industry resistance persisted, with stakeholders lobbying for reduced levies and delaying the regulation's full enforcement. This case study highlights the complex interplay between public health priorities and industry interest in food safety governance. It also demonstrates how crises can serve as catalysts for regulatory change, with the listeriosis outbreak playing a pivotal role in overcoming industry resistance and advancing the implementation of essential food safety measures.Item Extracts of southern African aquatic and wetland plant species as effective tyrosinase inhibitors(Elsevier, 2024-12) Lall, Namrita; Szuman, Karina; Madikizela, Bonani; Kok, Anna-Mari; De Canha, Marco Nuno; namrita.lall@up.ac.zaSouth Africa harvests approximately 19 500 tonnes of medicinal plants annually for the treatment of various ailments and an additional 6000 tonnes is exported globally for the development and design of cosmetic and medicinal products. South Africa is home to 30 freshwater and marine ecological regions, however, medicinal plant species from these semi-aquatic and aquatic habitats are largely understudied in comparison to other biomes. The lack of knowledge and reported pharmacological activity of these species may be hindering the potential contribution to the herbal medicine and personal care markets. South Africa is Africa's largest market for cosmetic and personal care products and in 2018 this sector reported 3.2 billion US dollars in revenue. Eighteen (18) Southern African freshwater aquatic and wetland plant species were selected and screened for their potential as cosmeceutical ingredients by investigating their antibacterial, anti-tyrosinase and cytotoxicity. The extracts of Erythrina zeyheri and Plantago longissima exhibited antimycobaterial activity with MIC values of 125 µg/mL. Two extracts of the genus Cyperus, C. marginatus and C. sexangularis showed tyrosinase inhibition with IC50 values of 75.03 and 64.26 µg/mL, respectively. Carex rhodesiaca and Gunnera perpensa both exhibited dual antimicrobial activity against Cutibacterium acnes with MIC values of 250 and 125 µg/mL, respectively and anti-tyrosinase activity with IC50 values of 64.71 and 70.43 µg/mL. Persicaria senegalensis exhibited anti-tyrosinase activity with an IC50 of 71.59 µg/mL. Fractionation of P. senegalensis yielded F14 with an IC50 of 68.77 µg/mL against tyrosinase enzyme activity. Purification of F3 yielded (24S)-Stigmast-5,22(E)-dien-3-β-ol which is the first report of this compound from this species. This study provides scientific validation of the traditional use of the selected species and provides proof of concept for further investigations of these extracts as potential active ingredients in the personal care sector.Item Evaluation of germination and early seedling growth of different grasses irrigated with treated mine water(MDPI, 2024-12) Mangwane, Mziwanda; Madakadze, Ignacio Casper; Nherera-Chokuda, Florence Veronica; Dube, Sikhalazo; Mndela, Mthunzi; Letsoalo, Ngoako; Tjelele, Tlou Julius; u14387027@tuks.co.zaCoal mining is known to have negative impacts on the environment, necessitating land rehabilitation after mining activities. Amongst the problems associated with coal mining is the accumulation of acid mine drainage characterized by large amounts of heavy metals and high acidity. The impact of these environmental problems on the ecosystem around mining areas underscores a need to devise strategies that will ensure sustainable restoration of the ecosystem integrity to ensure environmental protection. Of these, treatment of acid mine drainage using calcium sulfate dihydrate, which is subsequently used for irrigation during phytoremediation, holds great promise for restoration of open-cast mines. However, although grasses are used for rehabilitation of coal mined areas, the impacts of treated mine water on the germination, seedling emergence, and plant growth of grasses are not well known. The aim of the study was to evaluate the germination and early seedling growth responses of different forage grasses to treated mine water. Seven forage grass species were selected, with four species represented by two varieties while others were represented by one variety, totaling 11 forage grasses. For each plant entry, 100 seeds were placed in J.R. Petri’s dishes lined with Whatman No. 2 filter paper and watered with distilled and mine water to assess germination. For the seedling establishment experiment, only five species were studied, in which twenty seeds per species were sown in pots containing mine soil and irrigated using distilled and treated mine water. The final germination percentage (FGP), germination rate index (GRI), corrected germination rate index (CGRI), and T50 were determined for the germination trail and total biomass was assessed for the seedling growth trail. The highest FGP for all grasses was attained under controlled conditions, using distilled water, ranging from 38–94%. All grasses germinated when watered using treated mine water and had a FGP ranging from 20–91%. Relative to distilled water, GRI and CGRI were highest only for L. multiflorum cv AgriBoost when seeds were watered using the treated mine water. All grasses watered with treated mine water produced high biomass for the first two weeks, after which biomass production started to decline. Two grasses, Eragrostis curvula cv Ermelo and Lolium multiflorum cv Archie, showed tolerance to treated mine water irrespective of its high electrical conductivity (557 mS∙m−1). Therefore, these grasses could be used in the rehabilitation of coal-mined areas irrigated with treated mine water.Item Drivers of forest structure and biomass along a climatic gradient in the Soutpansberg, South Africa(Elsevier, 2025-09) Honold, Martin A.; Hilmers, Torben; Geldenhuys, Coert Johannes; Makhubele, Lucky; Van Tol, Johan J.; Ahmed, Shamim; Buys, Arno; Kotze, Elmarie; Tshidzumba, Ratsodo Phillip; Chirwa, Paxie W.; Tshaduli, Ndivhuwo; Araia, Mulugheta Ghebreslassie; Uhl, Enno; Pretzsch, HansForest structure plays a key role for providing different ecosystem services in rural regions worldwide. In forests and woodlands of southern Africa, there is a lack of quantitative information on prevailing structures, their abiotic and biotic drivers, as well as how stand characteristics will be affected by climate change. In this study, we established permanent research plots in mature developing stages of representative forests and woodlands occurring along a strong climatic gradient. Effects of site-available soil water and forest type were investigated for relevant dendrometric, as well as structural forest variables. We found site-available soil water having a significantly positive effect on all variables, apart from tree density and the ratio of multi-stem trees. Among the factors influencing site-available soil water, climate had a higher impact than topographical wetness index and soil available water capacity. Studied variables were also strongly influenced by the different forest and woodland types emerging, probably due to different species compositions, survival strategies and fire adaptations. Structural forest variables were revealed to have a positive effect on AGB especially in taller stands having enough space to form multiple canopy layers. In light of climate change with less soil water available and a related ongoing species and biome shift in southern Africa, our findings indicate that in the future, most of the studied forest variables, their related ecosystem functions and services are likely to decrease in the Soutpansberg region. The results of this study could be of use as input data for landscape level modelling, as well as for creating local management policies. HIGHLIGHTS • Forests and woodlands were investigated in a less studied region of South Africa. • Structural and dendrometric forest variables decreased with less water available. • Forest type played an important role apart from environmental drivers. • Structural heterogeneity showed a positive effect on AGB. • Climate change likely to reduce forest variables and related ecosystem functions.Item Taking stock of South Africa's flora(Elsevier, 2025-09) Le Roux, M. Marianne; Klopper, Ronell RenettSouth Africa is rich in plant biodiversity and has a longstanding history of record-keeping of its plant resources. In recent years, updated versions of the South African National Plant Checklist (Checklist) have been published annually in electronic form, reflecting changes from published taxonomic revisions and new species descriptions. The most recent Checklist from 2025 recognises 23 514 taxa and 21 539 species (20 204 indigenous and 1 329 naturalised species). Of the indigenous species, 60.5 % are endemic to the country. The e-Flora of South Africa project (e-Flora) was initiated in 2013 and the first phase was completed in 2020. Both the Checklist and e-Flora data were published online in 2024 on the South African National Biodiversity Institute’s Biodiversity Advisor website. The e-Flora adds a layer of descriptive information to the list of names provided in the Checklist, thereby enhancing the utility of these outputs for end-users from a variety of biodiversity-related fields. The e-Flora is a dynamic data source with updates guided by changes incorporated in the Checklist. An overview of the statistics from both the Checklist and the e-Flora, as of March 2025, are provided. HIGHLIGHTS • The South African National Plant Checklist recognises 21,539 species. • Species endemism is recorded at 60.5 %. • KwaZulu-Natal hosts the most number of families and genera while the Western Cape is most speciose. • The e-Flora of South Africa holds descriptions for 22,056 taxa. • Checklist and e-Flora data are accessible on the SANBI Biodiversity Advisor.Item Leaf anatomical traits of macadamia cultivars with potential links to drought tolerance(Elsevier, 2025-05) Maumela, Khodani; Taylor, Nicolette Jane; Oberlander, Kenneth Carl; Kritzinger, Angelique; angelique.kritzinger@up.ac.zaSelecting Macadamia cultivars with anatomical traits capable of withstanding drought may improve water management in their cultivation. Macadamia integrifolia, Macadamia tetraphylla, and their hybrids are commercially grown in South Africa for their high-value edible nuts, however, to improve yields, irrigation is required. This study examined leaf and petiole anatomical traits linked with plant water-use strategies in four commonly planted cultivars: ‘695′, ‘814′, ‘816′, and ‘A4’. Key traits investigated included stomatal density, mesophyll thickness (palisade and spongy parenchyma), vein density, and petiole Huber value. Fully matured macadamia leaves with their petioles were collected from Komatipoort, Nelspruit, and KwaZulu-Natal South Coast during the spring flush of 2021 and the summer flush of 2022 for anatomical analysis. Box plots illustrated significant variations in leaf and petiole anatomical traits among macadamia cultivars and regions. Cultivars ‘814′ and ‘695′ exhibited higher stomatal densities and higher vein densities, while cultivar ‘814′ also showed thicker mesophyll tissues and higher petiole Huber values. These traits suggest that cultivars ‘814′ and ‘695′ may have improved water transport and potential drought tolerance than cultivars ‘816′ and ‘A4’. Seasonal variation accounted for 45 % of the observed variability in leaf and petiole anatomy, highlighting a strong influence of environmental factors during leaf development. However, the anatomical variation was shaped not only by environmental factors but also by cultivar-specific characteristics. These findings suggest that these leaf and petiole anatomical traits could serve as indicators of drought tolerance and help improve the water management practices in macadamia cultivation, particularly in regions with inadequate rainfall. HIGHLIGHTS • The water requirements of macadamia trees remain unexplored. • Leaf and petiole anatomy varies significantly across cultivars and regions. • Environmental conditions and genetic factors influenced leaf and petiole anatomy. • Selecting drought-tolerant cultivars improves the water management practices in macadamia cultivation.Item Anti-acne and anti-hyperpigmentation potential of selected South African bryophytes with identification of oleamide as a lead compound(Elsevier, 2025-09) Paulsen, Alexander Quinn; Seaman, Jonathan Lloyd; Lall, Namrita; namrita.lall@up.ac.zaAcne vulgaris (AV), a chronic dermal inflammatory condition, affects approximately 9.4 % of the global population, with adolescents exhibiting the highest prevalence. Cutibacterium acnes is a key pathogenic factor in this chronic inflammatory condition, often resulting in post-inflammatory hyperpigmentation (PIH), which is primarily treated with tyrosinase inhibitors targeting melanin synthesis. While bryophytes are underexplored in modern cosmeceutical research, they have a history of use in traditional Chinese and Indian medicine for skin ailments. This study aimed to evaluate the antibacterial and anti-tyrosinase potential of three bryophyte species—Bryum argenteum Hedw., Fabronia pilifera Hornsch., and Leptodictyum riparium (Hedw.) Warnst.—to assess their utility in managing AV and PIH. Ethanolic (70 % v/v) extracts were prepared from rinsed and unrinsed plant material. Antibacterial activity against C. acnes (ATCC 6919) was assessed via PrestoBlue microtiter plate assays to determine the minimum inhibitory concentration (MIC) of the bryophyte ethanolic extracts. Tyrosinase inhibition was measured using colorimetric microtiter plate assays to evaluate anti-hyperpigmentation potential. Lead extracts were further analysed for their volatile constituents using gas chromatography-mass spectrometry (GC-MS). Rinsed B. argenteum extract exhibited the strongest antibacterial activity with an MIC of 31.25 μg/mL, followed by rinsed F. pilifera extract at 62.5 μg/mL. All extracts showed minimal tyrosinase inhibition, with IC₅₀ values exceeding the highest concentration tested. GC-MS analysis identified oleamide, a compound with known antibacterial properties, as the major volatile constituent (17.37 %–52.64 %), with the highest concentration of oleamide found in rinsed B. argenteum extract. These findings suggest that selected bryophytes, particularly B. argenteum, may serve as promising sources of antibacterial agents for the treatment of AV. Although pharmaceutically significant tyrosinase inhibition was not observed, the high oleamide content warrants further investigation through bioassay-guided fractionation. This study introduces bryophytes as novel candidates for cosmeceutical applications targeting acne-related skin concerns. HIGHLIGHTS • Determination of antibacterial activity of selected bryophyte species. • Variation in bioactivity and chemical profile between bryophyte extract preparations. • Antibacterial (Cutibacterium acnes) activity of rinsed Bryum argenteum and Fabronia pilifera with MICs of 31.25 μg/mL and 62.5 μg/mL respectively. • Oleamide is the primary volatile constituent of 70 % ethanolic B. argenteum and F. pilifera extracts.Item Adjuvant properties of selected medicinal plants for tuberculosis treatment(Elsevier, 2025-02) Kok, Anna-Mari; Meyer, Debra; Lall, Namrita; namrita.lall@up.ac.zaPlease read abstract in the article. HIGHLIGHTS • Many plant extracts with antimycobacterial activity have been identified recently. • Eucalyptus deglupta and Melianthus major had effective antioxidant capacity. • Searsia lancea showed significant hepatoprotection protection. • Increase in IL-12 by Eucalyptus deglupta and Sutherlandia frutescens.Item A review of the world's response to COVID-19 and the potential of medicinal plants for future pandemics(Elsevier, 2025-09) Alston, Brandon James; Maphutha, Jacqueline; Ackron, Jessica; Kok, Anna-Mari; Lall, Namrita; namrita.lall@up.ac.zaCoronavirus pandemics such as Spanish influenza, severe acute respiratory syndrome-coronavirus (SARS-CoV), middle east respiratory syndrome-coronavirus (MERS-CoV) and severe acute respiratory syndrome-coronavirus (SARS-CoV-2) have displayed high incidence and mortality rates prompting the need for repurposing of drugs, vaccine development and the investigation of medicinal plants. Research on previous coronaviruses has served as the foundation for COVID-19 (arising from SARS-CoV-2) research. Various medicinal plants such as Glycyrrhiza glabra, Ginkgo biloba, Curcuma longa and Artemisia annua have displayed favorable results against SARS-CoV-2. Medicinal plants as well as bioactive compounds derived from medicinal plants have been investigated in clinical trials to elucidate the effect on SARS-CoV-2. Several clinical trials evaluate the effect of the medicinal plant and bioactive compounds derived thereof on symptoms arising due to SARS-CoV-2 thus, the main aim of this review article is to highlight the gap in the investigation of the effect of medicinal plants and bioactive compounds on the specific mechanisms of COVID-19 in clinical trials. The review also highlights challenges pertaining to the standardization and quality control of medicinal plants as well as bioactive compounds derived from medicinal plants which may impede the feasibility of using medicinal plants in the clinical regimen for COVID-19 or future coronavirus pandemics. HIGHLIGHTS • SARS-CoV-2 is a highly infectious virus with high incidence and mortality rates. • Medicinal plants and bioactive compounds derived thereof are still relevant despite the use of repurposed antivirals (remdesivir) and vaccines. • Thorough clinical trials need to be conducted to elucidate the mechanism of action of medicinal plants and bioactive compounds derived thereof on COVID-19. • Gap in clinical trials leads to the use of unapproved medicinal plants and compounds which is a major health risk.Item Spatio-temporal dynamics of Isoberlinia-dominated woodlands in disturbance-prone landscapes over 15 years(Elsevier, 2025-06) Idjigberou, Shegoun Eudes; Assede, Emeline Sessi Pelagie; Biaou, Severin; Gouwakinnou, Gerard Nounagnon; Natta, Armand Kuyema; Biaou, Samadori Sorotori HonoreUnderstanding the impact of productivity and disturbance on vegetation succession is a crucial debate in community ecology, with significant implications for biodiversity conservation. Productivity and disturbance influence species richness and structure, enhancing our understanding of vegetation dynamics and species coexistence over time. Numerous theories, such as the Intermediate Stress Hypothesis, Intermediate Disturbance Hypothesis, and Dynamic Equilibrium Model, have been proposed to explain these mechanisms. However, our understanding of how productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands remains limited. We analyzed floristic data from sixteen sites with 64 permanent plots (400 m² each) along a south-north precipitation gradient (1112–991 mm per year) over 15 years (2006–2020). We calculated species richness and density for sapling and adult trees, and estimated two main variables: potential productivity using water deficit as a proxy, and disturbance intensity using logging rate. A linear mixed effects model, with plots nested within sites as random variables, was developed to test the effect of potential productivity and level of disturbance on species richness and density, for sapling and adult trees. Our results showed that species richness (SR) and density, for saplings and adult trees decreased over time, regardless of the disturbance and potential productivity gradients. Compared to higher levels of disturbance, low and medium levels of disturbance significantly increase the species richness of saplings and adult trees. In addition, the density of adult trees and saplings decreased over time, but increased with the level of disturbance from high to low. These results suggest that increased disturbance reduces the density of woodland species in favor of invasive species, typically savanna species. Overall, our results are consistent with the Dynamic Equilibrium Model, highlighting the complex interactions between disturbance regimes, productivity gradients, and their effects on species richness within ecosystems. Efficient forest management in Isoberlinia-dominated would avoid the high levels of logging that promote the establishment of invasive species and would maintain the biodiversity of this ecosystem in the long term. HIGHLIGHTS • Examined how the productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands. • Analyzed data from 64 permanent plots along a south-north precipitation gradient over 15 years. • Species richness and density for saplings and adult trees decreased over time. • Low to medium disturbance levels increase the richness of saplings and adult trees compared to higher levels. • Increased disturbance favored invasive savannah species over woodland species.