Research Articles (Plant Production and Soil Science)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1729

A collection containing some of the full text peer-reviewed/ refereed articles published by researchers from the
Department of Plant Production and Soil Science

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Diversity and distribution of Lophodermium species on non‑native Pinus species in the Southern Hemisphere
Theron, Cobus; Wingfield, Michael J.; Ahumada, R.; Carnegie, A.J.; Fraser, S.; Rodas, Carlos A.; Barnes, Irene (Springer, 2025-07-04)
Lophodermium species are amongst the most commonly isolated endophytic fungi on the needles and cones of pines. Of the 38 species reported on these trees, only Lophodermium seditiosum is considered a major pathogen. Species of Pinus have been widely established as non-natives in Southern Hemisphere countries, and several Lophodermium species have been reported on the needles of these trees. However, most of these reports are based on morphology alone. In this study, we considered the biogeography of Lophodermium species across the Southern Hemisphere by obtaining and identifying isolates from non-native Pinus species planted in Australia, Chile, Colombia, New Zealand, and South Africa. A multi-locus phylogenetic approach was used to delineate the species, and characteristic morphological features were evaluated against the resulting phylogeny. Phylogenetic analyses revealed the presence of five Lophodermium taxa on Pinus species in the Southern Hemisphere. A species belonging to the L. conigenum-australe complex was found in all countries except Chile. Lophodermium indianum and L. molitoris were found only in Colombian and New Zealand collections, respectively. Two distinct lineages of L. pinastri emerged from Chile, New Zealand, and Australia. None of the morphological features could distinguish between the different taxa of Lophodermium found, with several of the traits varying by host or location. Overall, the results support the fact that various cryptic Lophodermium species occur on the sampled Pinus species and suggest that several independent introductions of these fungi have occurred in Southern Hemisphere countries.
Assessing forest fragmentation and biodiversity impacts in sub-Saharan Africa : methodological challenges and conservation strategies for small-scale agricultural landscapes
Cheelo, Gillie; Shamaoma, Hastings; Chisanga, Charles Bwalya; Zekeng, Jules Christian; Syampungani, Stephen (Wiley, 2026-06)
Tropical forests in sub-Saharan Africa (SSA) harbor around one-third of the world's species but are becoming more fragmented due to the expansion of human settlements and small-scale agricultural (SCA) areas. This study systematically reviewed the approaches and methods used to analyze forest fragmentation and its impact on biodiversity in SSA, with a focus on their suitability in SCA landscapes. The main findings revealed that most studies in SSA employed generalized approaches to assess fragmentation, failing to account for the distinct contributions of various land cover changes. The other key findings indicate that the majority of studies (i) depended on low-resolution remote sensing imagery, (ii) neglected to assess landscape metrics accuracy, and (iii) had limited focus on socioeconomic aspects. These limitations impede precise and thorough evaluation of SCA's contribution to forest fragmentation. To address these gaps, we recommend the following: (i) adoption of high-resolution images, (ii) integration of socioeconomic data, and (iii) rigorous validation of landscape metrics. Concerning biodiversity implications, 55.2% (21 out of 38) of the reviewed studies reported negative impacts, and 68.2% (26 out of 38) exhibited a taxonomic bias toward avian and tree/plant species. We recommend the following: (i) enhanced utilization of remote sensing data for biodiversity monitoring, (ii) greater emphasis on neglected taxa (e.g., small mammals and amphibians), and (iii) focused conservation initiatives for small forest fragments, which are essential for biodiversity conservation, and reducing emissions from deforestation and forest degradation in SSA. PLAIN LANGUAGE SUMMARY The study found that small farm growing larger is the main reason animals and plants are disappearing in parts of Africa. We wanted to find ways to measure how these small farms break up forests and hurt wildlife, plants, and other living organisms. We learned that many studies have used poor-quality pictures from space and other general methods which miss important details found in small agriculture farms. Additionally, most studies on plants and animals in Africa have only focused on birds and trees. They ignore other types of creatures such as bees and frogs. Therefore, the study recommends (i) using better pictures from space and including information about people to understand how small farms affect nature, (ii) studying animals that are not often looked at, such as rats, rabbits, and frogs. Moreover, small patches of forest left between farms are important. They give birds, frogs, and rabbits a place to live and provide oxygen to breathe.
Rhizosphere bacterial communities of Namib Desert plant species : evidence of specialised plant-microbe associations
Maphosa, Silindile; Steyn, Megan; Lebre, Pedro Humberto; Gokul, Jarishma Keriuscia; Convey, Peter; Marais, Eugene; Maggs-Kolling, Gillian; Cowan, Don A. (Elsevier, 2025-04)
Rhizosphere microbial communities are intimately associated with plant root surfaces. The rhizosphere microbiome is recruited from the surrounding soil and is known to impact positively on the plant host via enhanced resistance to pathogens, increased nutrient availability, growth stimulation and increased resistance to desiccation. Desert ecosystems harbour a diversity of perennial and annual plant species, generally exhibiting considerable physiological adaptation to the low-water environment. In this study, we explored the rhizosphere bacterial microbiomes associated with selected desert plant species. The rhizosphere bacterial communities of 11 plant species from the central Namib Desert were assessed using 16S rRNA gene-dependent phylogenetic analyses. The rhizosphere microbial community of each host plant species was compared with control soils collected from their immediate vicinity, and with those of all other host plants. Rhizosphere and control soil bacterial communities differed significantly and were influenced by both location and plant species. Rhizosphere-associated genera included 67 known plant growth-promoting taxa, including Rhizobium, Bacillus, Microvirga, Kocuria and Paenibacillus. Other than Kocuria, these genera constituted the ‘core’ rhizosphere bacterial microbiome, defined as being present in > 90 % of the rhizosphere communities. Nine of the 11 desert plant species harboured varying numbers and proportions of species-specific microbial taxa. Predictive analyses of functional pathways linked to rhizosphere microbial taxa showed that these were significantly enriched in the biosynthesis or degradation of a variety of substances such as sugars, secondary metabolites, phenolic compounds and antimicrobials. Overall, our data suggest that plant species in the Namib Desert recruit unique taxa to their rhizosphere bacterial microbiomes that may contribute to their resilience in this extreme environment.
Harnessing exogenous membrane vesicles for studying Fusarium circinatum and its biofilm communities
Motaung, Thabiso Eric; Ratsoma, Manchela Francinah; Kunene, Sithembile; Santana, Quentin C.; Wingfield, Brenda D. (Elsevier, 2025-03)
Extracellular vesicles (EVs) are tiny messengers that convey bioactive molecules from donor to recipient cells, leading to changes in their physiology and function. We investigated the role of EVs in shaping growth and the biofilm biology of the tree pathogen Fusarium circinatum and its interaction with the susceptible host, Pinus patula. Vesicles were collected from fungal planktonic and biofilm cultures and from pine seedling needles and roots. The physical properties of these vesicles were analysed using nanoparticle tracking analysis and transmission electron microscopy, which revealed a diverse range of sizes and shapes, respectively. Furthermore, uptake of vesicles by conidia was conducted. The results demonstrated that F. circinatum EVs significantly but variably affected spore viability during the early phase (2–4 h) although they enhanced fungal biofilm integrity. In contrast, P. patula EVs greatly inhibited hyphal formation and biofilm biomass, but failed to inhibit matrix production in the fungal biofilm. Our results therefore show that conidial germination is essential for late fungal development including hyphal and biofilm formation while matrix production is a counter measure against harsh environmental conditions including the effects of plant-derived EVs.
Plant checklist for Table Mountain National Park and surrounding areas
Rebelo, Anthony G.; Holmes, Patricia M.; Klopper, Ronell Renett; Spear, Dian; Van Wilgen, Nicola J. (AOSIS, 2025-11-30)
Checklists play a fundamental role in biodiversity conservation by facilitating species monitoring, conservation planning and biogeographical assessments. The Cape Peninsula, South Africa, has a unique combination of nutrient-poor soils in a winter rainfall region, characterised by mountainous and coastal areas, all of which contribute to high levels of plant endemism. The Table Mountain National Park is a core conservation area within this global biodiversity hotspot, encompassing approximately 250 km² of diverse vegetation types, ranging from Sandstone, Granite, Shale and Sand Fynbos, to Afrotemperate Forest, Renosterveld and Strandveld and covers roughly 50% of the Cape Peninsula. Historical land use and urbanisation have also introduced a wide diversity of non-native species. This study presents an updated checklist of the flora of the park and surrounding peninsula, incorporating recent taxonomic revisions and newly recorded species. The checklist was compiled using data from herbarium records, conservation agency databases, citizen science platforms and historical surveys. Nomenclature follows the South African National Plant Checklist as of March 2024. The resulting dataset comprises 2785 plant taxa, excluding cultivated and urban parkland species. Asteraceae (300 taxa), Fabaceae (210) and Poaceae (173) emerged as the richest families, with Erica (118 species) as the most speciose genus. A total of 437 non-native naturalised plant taxa were recorded, with Fabaceae, Poaceae and Myrtaceae among the most diverse families. Additionally, 261 species are currently classified as threatened, including 38 Critically Endangered taxa. The Table Mountain National Park flora stands out as being among the most diverse within the South African National Parks network. CONSERVATION IMPLICATIONS : This updated checklist serves as a critical resource for conservation efforts, providing a baseline for future ecological research, climate change impact assessments, restoration initiatives and monitoring programmes. The data contribute to understanding species vulnerability and informing strategies for preserving the unique plant diversity of the Cape Peninsula.
Deeper bulbs are larger
Howard, Cody Coyotee; Attwood, Simon; Fourie, Carel; Hankey, Andrew J.; Harvey, Timothy S. (University of Chicago Press, 2025-07)
PREMISE OF RESEARCH : Belowground bud placement generally offers plants protection from aboveground disturbances, such as frosts and fires. However, deeper bud placement requires more reliance on stored resources for emergence. The aim of this study is to examine the relationship between the size of an underground storage organ and its depth within the soil across taxa. METHODOLOGY : We measured bulb diameter and bulb depth in the soil for 44 distinct species of Ledebouriinae (Scilloideae, Asparagaceae) found in Zambia and South Africa. PIVOTAL RESULTS : Across species, we found that larger bulbs are positioned deeper in the soil. At the individual level within species, a positive relationship between bulb diameter and bulb depth was generally found, except for in a few instances where larger and smaller bulbs appeared to be found at similar depths. CONCLUSIONS : Overall, our study suggests that deeper renewal bud positioning requires greater energetic costs (as indicated by larger bulbs) for emergence across species. Our within-species results could be interpreted as showing that older bulbous plants generally have larger, deeper bulbs. These characteristics are likely interrelated, where older plants have grown relatively larger bulbs that then allow for deeper bud placement, resulting in more protection from aboveground disturbances.
Microscale assessment of brush packing mulch as a method for enhancing soil moisture content and promoting delayed grass seedling mortality of subtropical grasses
Mangani, Tshepiso; Monegi, Piet; Mangani, Robert (Wiley, 2026-04)
Recurring droughts in South Africa's dryland rangelands have profound effects on ecosystem health. Consequently, identifying sustainable soil moisture content techniques is critical for enhancing plant growth to support ecosystem function. Soil moisture content was measured daily for five weeks using the field capacity as a reference and compared within the two mulching densities, high and low versus bare soil. The effect thereof was evaluated on growth parameters: emergence, relative growth, and survival rate of three subtropical grasses (Cenchrus ciliaris, Chloris gayan, and Panicum maximum) in seedling trays under a greenhouse. Soil moisture content significantly differed in all the treatments (p < 0.05); the mulching treatments retained half their moisture compared to the no cover treatment, which lost more than 77% moisture. The evapotranspiration was cumulatively lowest in the high-density mulching. Overall, Chloris gayana and Panicum maximum had the highest emergence (> 40%) and relative growth in the mulching treatments, while Cenchrus ciliaris emerged better (56%) and had relative growth in the no cover. By Week 6, many seedlings did not survive; however, Panicum maximum persisted in the high-density mulching with almost 17% seedlings survival. The mulching effect improved soil moisture content, thus providing more conducive conditions for germination and survival, especially of understorey grasses. While this approach is effective for certain grass species, it has demonstrated ecologically significant enhancement for soil moisture content and reducing evaporation, potentially promoting good soil structure and health.
Potential for production and use of liquid biofuels as a strategy for developing green and circular economies in Southern Africa
Dlamini, C.S.; Tshidzumba, Ratsodo Phillip; Gotore, T.; Kabia, G.; Munjoyo, R.S.M.; Kachamba, D. (NISC (Pty) Ltd and Informa UK Limited (trading as Taylor and Francis Group), 2026)
The Southern African Development Community (SADC) responded to global calls to address environmental challenges such as high greenhouse gas (GHG) emissions through the use of liquid biofuels. This study assessed the potential of liquid biofuel production in the SADC region with data collected in Malawi, Mozambique, South Africa and Zimbabwe. The results showed that the liquid biofuel industry is struggling. Countries do not have enough resources to support the industry effectively and there is overreliance on international sponsors. In terms of policy and regulatory frameworks most countries are doing well. However, these policies are not implemented effectively. Most countries use sugar-cane to produce bioethanol. Over the years countries, such as Malawi, have attempted to incorporate crops such as cassava (Manihot esculenta) and castor bean (Ricinus communis). Although the industry is not performing well it has contributed massively to livelihood development in all the region.
Comparative population genetics of Exserohilum turcicum in smallholder farms of Kenya and Uganda
Mahlangu, Jabulile N.N.; Berger, David Kenneth; Nsibo, David Livingstone (Wiley, 2026-01)
Exserohilum turcicum, the causal agent of northern leaf blight (NLB), poses a major threat to maize production in sub-Saharan Africa. Effective disease management depends on understanding the biology and population genetic structure of the pathogen, yet studies from Africa remain limited. Here, we investigated the genetic diversity and evolutionary forces shaping E. turcicum populations in Kenya and Uganda. A total of 494 strains were genotyped using 12 microsatellite markers. Gene diversity was relatively low in Kenya (He = 0.45) and Uganda (He = 0.42) compared with previous reports. Analysis of molecular variance revealed weak but significant differentiation between countries (ΦPT = 0.178, p = 0.001), with more variation occurring within countries (82%) than among them (18%). Cluster analyses showed high levels of gene flow within each country but limited admixture between countries, suggesting geographical barriers to dispersal. Grouping populations according to shared agroecological zones did not result in distinct genetic clustering, indicating that population structure was not driven by agroecological similarity. This interpretation was supported by a weak isolation-by-distance correlation (R2 = 0.077), consistent with restricted long-distance gene flow. Most populations deviated from the expected 1:1 mating-type ratio, highlighting the importance of clonal reproduction in shaping population structure. Collectively, these findings suggest that E. turcicum populations are largely panmictic within countries but exhibit restricted cross-country movement. These results provide a valuable foundation for developing sustainable, regionally targeted strategies to manage NLB in East Africa.
Bioactive compounds in European ferns : inhibition of pro-inflammatory enzymes and cytotoxic effects on cancer cells
Langhansova, Lenka; Dvorakova, Marcela; Matouskova, Petra; Pavicic, Antonio; Marsik, Petr; Esmear, Tenille; Lall, Namrita; Szotakova, Barbora (BioMed Central, 2026-03-11)
BACKGROUND : Ferns, among the oldest vascular plants, have been widely used in traditional medicine worldwide. While pharmacological studies predominantly focus on tropical and subtropical species, European ferns remain underexplored despite their potential to yield novel bioactive compounds. Given the limitations and side effects of existing anti-inflammatory and anticancer agents, European ferns represent a promising source of safer, naturally derived therapeutic options. METHODS : This study investigated the anti-inflammatory and anticancer properties of methanol extracts from 16 European fern species. The extracts were tested for their ability to inhibit pro-inflammatory enzymes of the arachidonic acid cascade, specifically cyclooxygenases (COX-1, COX-2) and 5-lipoxygenase (5-LOX). Cytotoxicity assays on SW480 human colon cancer cells, HeLa cervical cancer cells, CCD 841 CoN colorectal epithelial cells, and HepaRG liver cancer/non-cancer cells were performed to evaluate anticancer activity and toxicity. Flavonoid content analysis was conducted for selected species using LC/MS. RESULTS : Most fern extracts at low concentration of 10 µg/mL effectively inhibited COX-1, with Dryopteris cambrensis and Athyrium distentifolium achieving inhibition comparable to Ibuprofen (92% and 91%, respectively). Moderate inhibition of 5-LOX (over 50%) was observed across many species, while only a few, including Blechnum spicant, Dryopteris expansa, and D. aemula, moderately inhibited COX-2. Cytotoxicity screening identified five species, notably D. aemula and D. borreri, with significant activity against SW480 cells (IC50 = 79 and 115 µg/mL). A. distentifolium exhibited notable activity against HeLa cells. Despite cytotoxicity of active species toward non-cancerous CCD 841 CoN cells, HepaRG cell assays suggested a more favorable toxicity profile for most active species. CONCLUSIONS : This study reveals the significant anti-inflammatory and anticancer potential of European ferns, particularly their selective cytotoxicity in HepaRG cancer cells. These findings highlight European ferns as promising sources of therapeutic agents and encourage further exploration of their bioactive compounds for drug development.
Balancing soil fertility and emerging contaminants risk : insights from a 15-year biosolid application study under maize production
Tesfamariam, Eyob Habte; Ngoetjana, Matome Peter (MDPI, 2026-02)
Please read abstract in the article.
A self-regulating, low-energy, clay-based irrigation system : performance assessment in moringa and cowpea
Chaba, Hunadi; Tanaskovik, Vjekoslav; Araya, Hintsa; Cukaliev, Ordan; Araya, Nadia; Steyn, Martin Joachim; Truter, Mariette; Grundling, Althea; Trinath Suryadevara, Sai; Siering, Jan; Malchev, Svetoslav; Nechkovski, Stojanche; Arsov, Tosho; Goli, Imaneh; Azadi, Hossein (MDPI, 2026-02)
Crop failures are common in rain-fed farming in sub-Saharan Africa, especially in water-scarce South Africa. Inadequate rainfall necessitates innovative solutions to enhance food production. Water-saving irrigation technologies can significantly reduce crop failures, particularly for smallholder farms with limited access to irrigation water. This study evaluated the effects of Self-Regulating, Low-Energy, Clay-Based Irrigation System (SLECI), subsurface (SDI) and surface drip (DI) on the performance of moringa (Moringa oleifera) and cowpea (Vigna unguiculata), cultivated either as mono (sole) crops or in intercropping systems, in an open experimental field in South Africa. The experimental design was a factorial Randomized Complete Block Design (RCBD) replicated three times. The main aim was to assess water productivity and yield performance in different irrigation systems over two growing seasons. The results showed that the SLECI irrigation system was more suitable for M. oleifera, while V. unguiculata performed best with standard drip irrigation. Moringa oleifera fresh leaf biomass was higher under SLECI with sand around the clay element and surface drip irrigation with 1.42 t/ha, followed by the SLECI treatment without sand with 1.25 t/ha, while the least yield was noted in subsurface drip irrigation treatment with 1.18 t/ha. Vigna unguiculata (a dual-purpose crop for grain and leaves) produced higher total fresh biomass yield under subsurface drip irrigation treatment with 66.26 t/ha, followed by the SLECI treatment without sand (61.51 t/ha), while drip and SLECI with sand showed similar yield with 52.34 and 52.31 t/ha, respectively. In M. oleifera, the irrigation water productivity (IWP) varied from 0.26 kg/m3 below the surface to 0.65 kg/m3 after the SLECI treatment with sand. IWP in V. unguiculata treatments ranged from 27.52 kg/m3 in SLECI without sand to 9.52 kg/m3 under surface drip irrigation. In addition, chlorophyll content and stem diameter were elevated under SLECI, reflecting enhanced nutrient and water availability. The findings have important implications for sustainable agriculture under water-limited conditions.
Water use of macadamia trees is dynamically regulated by the presence or absence of fruit
Smit, Theunis Gerhardus; Taylor, Nicolette Jane; Midgley, Stephanie J.E. (Elsevier, 2026-04)
Please read abstract in the article. HIGHLIGHTS • Stomatal conductance increases in the presence of macadamia nuts at a canopy level. • Canopy increases in stomatal conductance result in increased canopy transpiration. • Crop load should be considered in water use models for irrigation scheduling.
Pinus-derived membrane vesicles disrupt pathogenic metabolism in fungi
Kunene, Sithembile; Mmushi, Tshepo Joseph; Steenkamp, Emma Theodora; Motaung, Thabiso Eric (Wiley, 2026)
• Much of what we know about the biological impacts of vesicles (MVs) is derived from Arabidopsis thaliana. Our study focused on vesicles from species in the non-model plant group, Pinus (pine) (P. elliottii, P. radiata, and P. patula × Pinus tec (hybrid)). These plants have tougher tissues and strong, acicular-shaped leaves (needles). • Herein, we first developed a protocol to guide effective collection of juice fluid from needles and roots in a clean and efficient manner. The effects of these vesicles were characterized in terms of the global nutrient profile of the pine pitch canker fungus, Fusarium circinatum, generated from growing fungal spores on ~400 substrates embedded across BioLog phenotypic microarray (PM) plates (PM1, PM2A: carbon sources; PM3B: nitrogen sources; PM9: osmolytes/pH; PM24C: chemicals). • Our findings revealed that MVs, specifically needle-derived MVs (ndMVs) from P. elliottii, disrupt metabolite assimilation in several important pathways, including carbon and nitrogen metabolism. The PM data were also strongly correlated with observed phenotypic effects, including reduced viability and germination of spores in liquid media, as well as impaired filamentous growth on solid media. Importantly, these MV-induced phenotypic effects were reproducible in other filamentous pathogens (e.g., Botrytis cinerea, Chrysoporthe cubensis and F. graminearum) and during a glasshouse trial conducted with F. circinatum-infected P. elliottii seedlings, demonstrating the stable biological effects of ndMVs. • Cumulatively, our results suggest that plant-derived vesicles can disrupt metabolism in pathogenic fungi and, therefore, serve as a cost-effective and sustainable source of novel plant protection molecules.
Friends or foes? Polyploidy and competition in a grassland geophyte
De Sousa, Damian Vaz; Greve, Michelle; Taylor, Nicolette Jane; Oberlander, Kenneth Carl (Wiley, 2026-02)
Previous studies have suggested polyploids may possess a competitive advantage over diploids, due to their larger size, increased vigour or ability to better respond to abiotic stress. However, few studies have tested the effect of polyploidy on competitive ability directly, and only relatively recently has this oversight begun to be addressed. Here we assessed potential differences in competitive ability between diploids and tetraploids of a widespread African grassland geophyte, Oxalis obliquifolia. Diploid and tetraploid plants were grown in identical environmental conditions under four different competition scenarios. As a control, diploids and tetraploids were grown under solitary conditions. For intra-cytotype competition, pairs of diploids and tetraploids were planted together. Inter-cytotype competition involved planting individual diploids and tetraploids with one another, and for interspecies competition individual diploids and tetraploids were planted with Themeda triandra seedlings. Thirty-seven morphological, physiological and phenological traits were recorded and assessed for associations between cytotype and competition treatment using ordinations and GLMs. Ordination showed diploids and tetraploids as distinct clusters, with very little separation based on competition treatment. Univariate analyses showed tetraploids have larger but fewer organ structures than diploids, suggesting a tradeoff between these traits. Tetraploids also produce larger seeds. Diploids showed reduced numbers of leaves and were more negatively impacted by interspecies competition than tetraploids, suggesting tetraploids may potentially be the better interspecies competitor. Tetraploids also extended their flowering season in response to inter-cytotype and interspecies competition. Cytotypes respond differently under different competition treatments, and tetraploids may have a competitive advantage over diploids. However, this potential competitive asymmetry does not explain observed cytotype sympatry. Tetraploids also appear to differentiate between intra-cytotype competition, and competition with diploids and other species. The potential for abiotic factors to impact these competition dynamics remains unexplored.
Advances and shortfalls in knowledge of Antarctic terrestrial and freshwater biodiversity
Pertierra, Luis R.; Convey, P.; Barbosa, A.; Biersma, E.M.; Cowan, Don A.; Diniz, J.A.F.; De los Rios, A.; Escribano-Alvarez, P.; Fraser, C.I.; Fontaneto, D.; Greve, Michelle; Griffiths, H.J.; Harris, Mathew Andrew; Hughes, K.A.; Lynch, H.J.; Ladle, R.J.; Liu, X.P.; Le Roux, Peter Christiaan; Majewska, R.; Molina-Montenegro, M.A.; Peck, L.S.; Quesada, A.; Ronquillo, C.; Ropert-Coudert, Y.; Sancho, L.G.; Terauds, A.; Varliero, Gilda; Vianna, J.A.; Wilmotte, A.; Chown, S.L.; Olalla-Tárraga, M.A.; Hortal, J. (American Association for the Advancement of Science, 2025-02)
Antarctica harbors many distinctive features of life, yet much about the diversity and functioning of Antarctica’s life remains unknown. Evolutionary histories and functional ecology are well understood only for vertebrates, whereas research on invertebrates is largely limited to species descriptions and some studies on environmental tolerances. Knowledge on Antarctic vegetation cover showcases the challenges of characterizing population trends for most groups. Recent community-level microbial studies have provided insights into the functioning of life at its limits. Overall, biotic interactions remain largely unknown across all groups, restricted to basic information on trophic level placement. Insufficient knowledge of many groups limits the understanding of ecological processes on the continent. Remedies for the current situation rely on identifying the caveats of each ecological discipline and finding targeted solutions. Such precise delimitation of knowledge gaps will enable a more aware, representative, and strategic systematic conservation planning of Antarctica.
Quality and quantity losses of tomatoes grown by small-scale farmers under different production systems
Molelekoa, Tintswalo; Karoney, Edwin M.; Siyoum, Nazareth; Gokul, Jarishma Keriuscia; Korsten, Lise (MDPI, 2025-08-01)
Postharvest losses amongst small-scale farmers in developing countries are high due to inadequate resources and infrastructure. Among the various affected crops, tomatoes are particularly vulnerable; however, studies on postharvest losses of most fruits and vegetables are limited. Therefore, this study aimed to assess postharvest tomato losses under different production systems within the small-scale supply chain using the indirect assessment (questionnaires and interviews) and direct quantification of losses. Farmers reported tomato losses due to insects (82.35%), cracks, bruises, and deformities (70.58%), and diseases (64.71%). Chemical sprays were the main form of pest and disease control reported by all farmers. The direct quantification sampling data revealed that 73.07% of the tomatoes were substandard at the farm level, with 47.92% and 25.15% categorized as medium-quality and poor-quality, respectively. The primary contributors to the losses were decay (39.92%), mechanical damage (31.32%), and blotchiness (27.99%). Postharvest losses were significantly higher under open-field production systems compared to closed tunnels. The fungi associated with decay were mainly Geotrichum, Fusarium spp., and Alternaria spp. These findings demonstrate the main drivers behind postharvest losses, which in turn highlight the critical need for intervention through training and support, including the use of postharvest loss reduction technologies to enhance food security.
From species to pixels : monitoring rangeland quality & productivity by leveraging the NDVI-RCI relationship
Nondlazi, Basanda Xhantilomzi; Cho, Moses Azong; Mantlana, Brian Khanyisa; Ramoelo, Abel (Routledge, 2026)
Grasslands are highly vulnerable to climate and changes in grazing management, yet little is known about the national rangeland response to long-term (>18 years) grazing management that may confound climate effects. This study assessed the correlation between Normalized Difference Vegetation Index (NDVI), i.e., productivity and Rangeland Condition Index (RCI) i.e., quality and predicted historical grazing management (26 years) using Ecological Index Method (EIM) analysis of 72 relevés in the Highland Sourveld (HSV). Relationships between 150 NDVI and 72 RCI samples showed a rate of 0.125 change in NDVI for every 12.5% change in RCI. In 1983, the HSV’s rangeland carrying capacity (RCC) ranged from 2.0 - 2.2 ha/AU/yr (land required to support one mature bovine for 1 year), with an NDVI of 0.43, like the benchmark. site. By 2009, the RCC decreased to 3.2 ha/AU/yr, with NDVI <0.30. Selective overgrazing, reduced RCC by increasing Increaser II species and reducing Decreaser species presence. Findings suggest combining NDVI and RCI is more effective than using either alone. Integrating remote sensing with traditional ecological data (Ecological Remote Sensing - eRS) improves our understanding of rangeland vulnarability, thus, ideal for permanent monitoring of public rangelands in South Africa.
Two new endemic species of Hermannia L. (Malvaceae: Byttnerioideae)-H. lilacina and H. boschbergensis-from the Cape Midlands Escarpment (Eastern Cape, South Africa)
Clark, V. Ralph; Vidal Jr, Joao De Deus; Gwynne-Evans, David; Barker, Nigel (Elsevier, 2026-03)
Hermannia L. is primarily an African genus of some 250 species, with the centre of diversity located in southern Africa. It is the sixth-most endemic-rich genus in the Greater Cape Floristic Region, although endemics occur in all biomes in southern Africa. Two new species of Hermannia L. (Malvaceae: Byttnerioideae) are described from the Cape Midlands Escarpment mountains, Eastern Cape Province of South Africa. Hermannia lilacina Gwynn. & V.R.Clark is common in Karoo Escarpment Grassland (Grassland Biome), mostly above 1600 m in the eastern Sneeuberg Massif (Nardousberg to Aasvoëlkrans, i.e. behind Graaff-Reinet to Pearston), with one record from the interior of the western Great Winterberg–Amatholes (i.e. near Tarkastad). Hermannia boschbergensis Gwynn. & V.R.Clark is apparently confined to mid-elevations in Eastern Cape Escarpment Thicket (Albany Thicket Biome) at 1200 m on the Boschberg (eastern Sneeuberg, near KwaNajoli/Somerset East) and is currently only known from two collections. Recognition of these two new species complements numerous other recent discoveries from these mountains. HIGHLIGHTS • Two new species of Hermannia are described from the Eastern Cape, South Africa. • Hermannia lilacina is endemic to the Sneeuberg and Great Winterberg–Amatholes. • Hermannia boschbergensis is endemic to the Boschberg (Sneeuberg). • Eastern Cape endemic Hermannia are doubled from two to four taxa.
Intra-island variation in wind patterns on sub-Antarctic Marion Island
Schoombie, Janine; Craig, K.J. (Kenneth); Goddard, Kyle Andrew; Hedding, D.W. (David William); Nel, W.; Le Roux, Peter Christiaan (University of Pretoria, 2025-10)
Sub-Antarctic Marion Island provides a critical habitat for pelagic species, yet its terrestrial ecosystem faces increasing threats from climate change. Despite being situated in one of the windiest regions globally, the impact of changing wind patterns at the intra-island scale remains poorly understood. Existing datasets lack the spatial resolution necessary to capture fine-scale wind dynamics across the island. This study aimed to address this gap by presenting high-resolution wind speed and direction data to investigate the effects of wind on terrestrial systems. We present two complementary datasets: (1) wind measurements collected from 17 stations distributed across the island between May 2018 and March 2021, and (2) computational fluid dynamics (CFD) simulations providing wind vectors and associated properties at a 30 × 30 m resolution for heights up to 200 m above ground level. The data reveal significant differences in wind speed and direction across different geographical sectors of Marion Island. Notably, anemometers situated in the south recorded more frequent gale-force winds, while the western stations experienced calmer conditions. By using the observed wind direction frequencies, a weighted average vector plot was generated from the CFD simulations, providing an island-scale representation of spatial wind patterns across the island. These datasets offer valuable insights into variations in wind patterns, including upstream and downstream effects, and serve as a crucial resource for studying wind-driven processes affecting the landscape and ecosystem, such as seed dispersal.

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