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
Browse
Recent Submissions
Now showing 1 - 20 of 1053
Item Growth analysis of pearl millet genotypes grown under different management practices(MDPI, 2025-03) Ausiku, Petrus Ausiku; Annandale, John George; Steyn, Martin Joachim; Sanewe, Andrew; u14431786@tuks.co.zaPearl millet is a cereal crop vital for food security in Africa and Asia. It is widely adapted for dual-purpose production, providing grain for human consumption and fodder for livestock, particularly during dry seasons. This study aimed to evaluate three dual-purpose pearl millet genotypes from Namibia and South Africa while exploring prospects for future production practices. Growth analysis is essential for quantitatively assessing crop growth, development, and production. A growth analysis study was conducted by collecting and evaluating weather data, water use efficiency, and crop growth parameters that are valuable for modelling, allowing for observing and quantifying strengths and weaknesses between varieties for food and fodder or as dual-purpose varieties. The analysis focused on water use, plant height, fractional radiation interception, panicle number, tiller number, flowering date, stem diameter, panicle length, dry matter distribution, harvest index, grain yield, and panicle diameter, under well-watered, supplementary irrigation, and rainfed conditions. The landrace achieved a higher yield under well-watered conditions than the hybrid and improved varieties. The hybrid pearl millet produced a greater fodder yield than the improved short variety in well-watered and water-limited treatments. The improved variety suits grain production, whereas the landrace and hybrid are more suitable for dual-purpose production. The landrace performed well in rainfed and irrigated situations across the three seasons. The landrace (Kantana) recorded the highest grain yield (1.01 kg m−2), followed by the hybrid (Agrigreen) (0.97 kg m−2), while the improved variety (Kangara) had the lowest grain yield (0.74 kg m−2).Item Investigating abiotic and biotic parameters associated with gradually declining Valencia citrus trees in South Africa(Southern Cross Publishing, 2024-02-29) Pretorius, Mathys C.; Labuschagne, Nico; Daneel, M.; Raath, Pieter; Cadet, P.; McLeod, Adele; nico.labuschagne@up.ac.zaThe current study determined if a combination of biotic and abiotic parameters could differentiate Citrus sinensis trees (three categories based on visual tree canopy status) with root disease-related decline symptoms in two citrus orchards. Two experimental sites, containing a range of healthy and different stages of decline trees, were randomly selected. Three decline category trees were selected with abiotic and biotic parameters associated with decline measured. Principal component analyses of 41 soil, leaf, root and trunk associated parameters ordered the category 1 to 3 trees chronologically on the factorial plan for both orchards. However, the parameters only described a low level of the variability. Only the healthy (category 1) and more diseased (category 3) trees were studied further. Soil electrical conductivity and leaf %N, were the only parameters differing significantly between the two categories in both orchards, but both parameters were significantly higher in category 3 trees in orchard 1 whereas the opposite was true for orchard 2 with significantly higher values in category 1 trees. In the more severely declining MP1 orchard, parameters differing significantly between the two categories included soil Na, cation exchange capacity and leaf Fe, B, Mo and Zn. In orchard MP2, parameters were soil %C, soil citrus nematodes, leaf size and leaf %Na and %Mg. Discriminant analysis indicated that leaf parameters were more specifically associated with decline. Leaf nutrient status can possible be an additional process to indicate decline.Item Dispersal potential does not predict recent range expansions of sub-Antarctic plant species(Springer, 2024-05) Mazibuko, Nompilo; Greve, Michelle; Le Roux, Peter ChristiaanDispersal influences many key aspects of plant ecology at both fine- and broad scales. However, dispersal events are challenging to quantify as they are difficult to observe and measure accurately, despite the importance of understanding species’ dispersal capacity. In this study, we quantified dispersal estimates for the dominant vascular flora of sub-Antarctic Marion Island, using a mechanistic model to estimate dispersal potential via anemochory and standardized experiments that simulate dispersal events via zoochory, human activity, and thalassochory, to test if dispersal capacity correlates to contemporary range expansion of the island’s native and alien species. Our results demonstrate the broad range of dispersal potential in the island’s flora and represent the first quantification of the dispersal potential (via multiple vectors) of the dominant vascular flora in the sub-Antarctic. Dispersal potential was not related to range expansion rates of native or alien species, suggesting that other mechanisms are responsible for the variation observed in species range expansion rates. Although this finding contradicts expectations and evidence from some other studies, it is consistent with research conducted in alpine regions (which may be climatically and physiognomically similar to this sub-Antarctic study site) where factors such as demography and competition are more important predictors of species range expansion than their dispersal ability, dispersal syndromes, or dispersal-related traits.Item Advancements in Spongospora subterranea : current knowledge, management strategies, and research gaps(Springer, 2024-12) Strydom, R.F.; Wilson, C.R.; Tegg, R.S.; Balendres, M.A.; Van der Waals, Jacqueline ElisePowdery scab was first documented on locally sampled potatoes in Braunschweig, Germany. A hundred and eighty-one years later, the disease has spread globally to most potato-producing regions and is considered one of the most destructive potato diseases. Here, we review the knowledge of powdery scab and causative agent, Spongospora subterranea f. sp. subterranea, highlighting research progress made in the last 7 years. Much work has been done to increase our understanding of how zoospores respond to their environment (e.g. root exudates, Ca2C signalling, and root metabolites) and the management of the disease by chemical and biological control agents. Recent research has utilised omics approaches — metabolomics, proteomics, and genomics — to gain a deeper understanding of the host–pathogen interaction in the powdery scab pathosystem. The management of powdery scab can be achieved using a combination of strategies that include (1) the planting of resistant potato varieties, (2) strategies that avoid disease (field selection and planting date), those that (3) reduce initial soil inoculum (crop rotation, organic soil amendments, and soil fumigation), and (4) in-crop approaches (soil chemical applications, biological control, proper field, fertility, crop, irrigation management, and crop sanitation). Lastly, we discuss research gaps for future research, including the disease’s interaction with other potato diseases that may be impacting disease expression and opportunities to enable a greater understanding of the powdery scab pathosystem.Item Exceptional and enigmatic southern African Oxalis – a review(Elsevier, 2025-07) Dreyer, Laurette; Oberlander, Kenneth CarlOxalis is a diverse, morphologically variable, and biologically unusual member of South Africa’s flora, but has seen surprisingly little research focus despite its relevance to multiple ecological and evolutionary questions. In this review we sketch what makes this lineage exceptional in terms of what is known, and enigmatic in terms of what still needs attention, through the lens of three decades of research focus on our part. Our hope is to focus attention on, and stimulate research interest in, this extraordinary genus.Item Elevated carbon dioxide only partly alleviates the negative effects of elevated temperature on potato growth and tuber yield(Springer, 2025-03) Kiongo, Simon Chege; Taylor, Nicolette Jane; Franke, A.C.; Steyn, Joachim Marthinus; martin.steyn@up.ac.zaPlease read abstract in the article.Item Ecosystems managed for wildlife and livestock : contrasting herbivore impacts in a heavily grazed African savanna(Elsevier, 2024-12) Voysey, Michael D.; Archibald, Sally; Harris, Mathew Andrew; Hempson, Gareth P.; Greve, MichelleReplacement of diverse wild herbivore assemblages by livestock across expansive regions of African savanna grassland is predicted to modify tree-grass interactions. Yet, despite the ubiquity of this herbivore regime change, consequences of shifting from wildlife to livestock for savanna ecosystems are poorly resolved. We assessed the effects of livestock grazing on the herbaceous community of a nutrient rich, semi-arid savanna. Direct and indirect impacts - moderated via differences in tree cover - of intensive cattle grazing in communal rangelands, on the herbaceous community were contrasted with heavily utilized wild herbivore grazing systems. Communal rangelands showed a more than two-fold increase in woody cover compared to wildlife areas. Herbaceous differences between wildlife and livestock areas were driven primarily by changes in the area beneath trees, and differences in how densely wooded areas are used by wildlife and livestock. In wildlife systems, grazing intensity was much lower below than away from tree canopies, whereas in livestock systems grazing intensity was high irrespective of tree canopy presence. Away from trees, structure and functional traits of herbaceous vegetation were markedly similar between the two herbivory systems. In our study area, communal rangelands used by livestock, predominantly cattle, are not a degraded subset of wildlife areas but support near equivalent diversity, although with different grass and forb species, and warrants consideration when evaluating their contribution to biodiversity conservation in the region. Nonetheless, higher bare ground cover and the lack of tall-grass reserves mean that communally managed rangelands with low grazer diversity might be more sensitive to intra- and inter-annual climate variability since they are associated with lower forage variability.Item Benthic macroinvertebrates as bioindicators of stream health within the Central African Copperbelt(Springer, 2025-07) Ouma, Kennedy O.; Shane, Agabu; Monde, Concillia; Syampungani, StephenGlobally, stream ecosystem health in mining regions, including the Central African Copperbelt (CACB), is threatened by increased aquatic metal pollution. Stream biomonitoring and bioassessment offers an eco-friendly nature-based approach to determine the aquatic ecological conditions and inform management interventions in mining landscapes. This study conducted monthly between May 2022 and April 2023, explored the taxonomic and functional responses of macroinvertebrates as bioindicators of the ecological condition of four streams in the north-western Zambian Copperbelt of the CACB. 252 sediment samples were collected and analysed for metals. 144 macroinvertebrate samples were collected to determine their taxonomic and functional traits. ANOVA (analysis-of-variance), SIMPER (similarity-percentage), ANOSIM (analysis-of-similarities), CCA (canonical correspondence analysis) and multidimensional biotic index analyses were conducted to correlate environmental and biotic variables. Metal concentrations (mg/kg) in sediments followed the order As (5.27) < Pb (5.75) < Zn (44.6) < Ni (89.3) < Cu (187.5). From ANOVA, the macroinvertebrate community was significantly dominated by Insecta families, mostly Diptera (23.3%) and Coleoptera (16.7%). Trophically, predators significantly dominated in the order Odonata (34.7%) > Hemiptera (31.8%) > Diptera (18.9%). SIMPER depicted a strong influence of Cu, EC, velocity, sediment texture and organic matter on macroinvertebrate diversity and spatial distribution. ANOSIM indicated the highest community dissimilarity at the most impacted stream (KYABR). Habitat assessment metrics, including ZISS-1, ASPT, and EPT/Chironomidae ratio, registered a “good ecological status” with the presence of pollution-sensitive taxa (Helodidae and Perlidae), in concordance with environmental variables, confirming the suitability of macroinvertebrates as proxy bioindicators of stream health in mining landscapes. The study confirms the potential of macroinvertebrates, as potential bioindicators of stream health in mining landscapes. Their diversity and distribution is strongly influenced by Cu, EC, velocity, and sediment characteristics while habitat assessment metrics indicate a "good ecological status" despite moderate metal contamination.Item Unforeseen plant phenotypic diversity in a dry and grazed world(Nature Research, 2024-08) Gross, Nicolas; Maestre, Fernando T.; Liancourt, Pierre; Berdugo, Miguel; Martin, Raphael; Gozalo, Beatriz; Ochoa, Victoria; Delgado-Baquerizo, Manuel; Maire, Vincent; Saiz, Hugo; Soliveres, Santiago; Valencia, Enrique; Eldridge, David J.; Guirado, Emilio; Jabot, Franck; Asensio, Sergio; Gaitan, Juan J.; Garcia-Gomez, Miguel; Martinez, Paloma; Martinez-Valderrama, Jaime; Mendoza, Betty J.; Moreno-Jimenez, Eduardo; Pescador, David S.; Plaza, Cesar; Pijuan, Ivan Santaolaria; Abedi, Mehdi; Ahumada, Rodrigo J.; Amghar, Fateh; Arroyo, Antonio I.; Bahalkeh, Khadijeh; Bailey, Lydia; Ben Salem, Farah; Blaum, Niels; Boldgiv, Bazartseren; Bowker, Matthew A.; Branquinho, Cristina; Van den Brink, Liesbeth; Bu, Chongfeng; Canessa, Rafaella; Castillo-Monroy, Andrea del P.; Castro, Helena; Castro, Patricio; Chibani, Roukaya; Conceicao, Abel Augusto; Darrouzet-Nardi, Anthony; Davila, Yvonne C.; Deak, Balazs; Donoso, David A.; Duran, Jorge; Espinosa, Carlos; Fajardo, Alex; Farzam, Mohammad; Ferrante, Daniela; Franzese, Jorgelina; Fraser, Lauchlan; Gonzalez, Sofia; Gusman-Montalvan, Elizabeth; Hernandez-Hernandez, Rosa Mary; Hoelzel, Norbert; Huber-Sannwald, Elisabet; Jadan, Oswaldo; Jeltsch, Florian; Jentsch, Anke; Ju, Mengchen; Kaseke, Kudzai F.; Kindermann, Liana; Le Roux, Peter Christiaan; Linstaedter, Anja; Louw, Michelle Anne; Mabaso, Mancha; Maggs-Koelling, Gillian; Makhalanyane, Thulani P.; Issa, Oumarou Malam; Manzaneda, Antonio J.; Marais, Eugene; Margerie, Pierre; Hughes, Frederic Mendes; Messeder, Joo Vitor S.; Mora, Juan P.; Moreno, Gerardo; Munson, Seth M.; Nunes, Alice; Oliva, Gabriel; Onatibia, Gaston R.; Peter, Guadalupe; Pueyo, Yolanda; Quiroga, R. Emiliano; Ramirez-Iglesias, Elizabeth; Reed, Sasha C.; Rey, Pedro J.; Reyes Gomez, Victor M.; Rodriguez, Alexandra; Rolo, Victor; Rubalcaba, Juan G.; Ruppert, Jan C.; Sala, Osvaldo; Salah, Ayman; Sebei, Phokgedi Julius; Stavi, Ilan; Stephens, Colton; Teixido, Alberto L.; Thomas, Andrew D.; Throop, Heather L.; Tielboerger, Katja; Travers, Samantha; Undrakhbold, Sainbileg; Val, James; Valko, Orsolya; Velbert, Frederike; Wamiti, Wanyoike; Wang, Lixin; Wang, Deli; Wardle, Glenda M.; Wolff, Peter; Yahdjian, Laura; Yari, Reza; Zaady, Eli; Zeberio, Juan Manuel; Zhang, Yuanling; Zhou, Xiaobing; Le Bagousse-Pinguet, YoannEarth harbours an extraordinary plant phenotypic diversity1 that is at risk from ongoing global changes. However, it remains unknown how increasing aridity and livestock grazing pressure—two major drivers of global change—shape the trait covariation that underlies plant phenotypic diversity. Here we assessed how covariation among 20 chemical and morphological traits responds to aridity and grazing pressure within global drylands. Our analysis involved 133,769 trait measurements spanning 1,347 observations of 301 perennial plant species surveyed across 326 plots from 6 continents. Crossing an aridity threshold of approximately 0.7 (close to the transition between semi-arid and arid zones) led to an unexpected 88% increase in trait diversity. This threshold appeared in the presence of grazers, and moved toward lower aridity levels with increasing grazing pressure. Moreover, 57% of observed trait diversity occurred only in the most arid and grazed drylands, highlighting the phenotypic uniqueness of these extreme environments. Our work indicates that drylands act as a global reservoir of plant phenotypic diversity and challenge the pervasive view that harsh environmental conditions reduce plant trait diversity8,9,10. They also highlight that many alternative strategies may enable plants to cope with increases in environmental stress induced by climate change and land-use intensification.Item Improving success rates of remote conservation translocations by mitigating harsh in-situ environmental conditions : a case study on a critically endangered succulent(Elsevier, 2025-03) Frisby, Arnold Walter; Momberg, Mia; Le Roux, Peter Christiaan; arnold.frisby@up.ac.zaConservation translocations of threatened plants are an important measure used to curb extinctions. Some translocation attempts have had poor success rates, particularly in remote locations where after-care is difficult, and this type of intervention often lacks empirical data to inform protocols for subsequent attempts. To address this issue, we undertook a conservation translocation on a Critically Endangered succulent (Aloe peglerae), with the aim of identifying factors that promote survival rates of transplanted seedlings in remote areas of suitable habitat. Protection from the sun, through shading by grass tussocks, improved survival rates of transplanted seedlings significantly during all three years within the study period. Survival rates were also higher for larger seedlings, but the latter effect was only observed during the first-year post-transplantation. Seedling growth differed between years (being highest in the wettest year), and was improved by the applications of potassium silicate (K2SiO3) during cultivation, a biostimulant that increases drought tolerance in plants. All the observed positive effects on seedling growth were, however, only significant during the first-year post-transplantation. Fire exposure negatively affected seedling growth, but also only during the first-year. Based on these results, a suggested protocol for guiding the planning and implementation of conservation translocations of threatened succulent plant species is provided. This study illustrates the value of generating empirical data prior to undertaking larger scale conservation translocations to maximise resource use and increase success rates. The use of a biostimulant is a novel approach to the field of conservation translocations, and could have wide-ranging applications.Item IMA GENOME-F20 a draft genome assembly of Agroathelia rolfsii, Ceratobasidium papillatum, Pyrenopeziza brassicae, Neopestalotiopsis macadamiae, Sphaerellopsis filum and genomic resources for Colletotrichum spaethianum and Colletotrichum fructicola(Pensoft Publishers, 2025-02) D’Angelo, Davide; Sorrentino, Roberto; Nkomo, Tiphany; Zhou, Xianzhi; Vaghefi, Niloofar; Sonnekus, Byron; Bose, Tanay; Cerrato, Domenico; Cozzolino, Loredana; Creux, Nicky; D'Agostino, Nunzio; Fourie, Gerda; Fusco, Giovanna; Hammerbacher, Almuth; Idnurm, Alexander; Kiss, Levente; Hu, Yanping; Hu, Hongli; Lahoz, Ernesto; Risteski, Jason; Steenkamp, Emma Theodora; Viscardi, Maurizio; Van der Nest, Magrieta Aletta; Wu, Yuan; Yu, Hao; Zhou, Jianjin; Dewage, Chinthani S. Karandeni; Kotta-Loizou, Loly I.; Stotz, Henrik U.; Fitt, Bruce D.L.; Huang, Yong-Ju; Wingfield, Brenda D.; brenda.wingfield@up.ac.zaItem Evaluating undergrowth species pattern and soil seed banks mode for monitoring conservation in a protected forest of Nigeria(Springer, 2025) Omomoh, Bernard Eromosele; Aigbe, Precious Daniel; Alli, Busayo Janet; Ogunsanwo, Gbenga Elijah; Akomolafe, Gbenga Festus; Adeniji, Oluwafemi Adebayo; Agbede, Isaac KolawoleAs most trees enter senescence, the assessment of undergrowth species and seedling outcomes from soil seed banks becomes imminent research and an essential tool to checklist an area prioritized for tree conservation. The procedure to ascertain senescent trees are not underrepresented is uncommon research, specifically for a buffer zone of a Strict Nature Reserve (SNR) in the Akure Forest Reserve. This study evaluates the species richness of the undergrowth patterns that are prioritized for conservation and also examines the effective soil depths for seedling outcomes. However, four (4) sample plots (50 × 50 m2) from lowlands were established at the buffer zone of a protected forest to measure the population size of the undergrowth species pattern. Similarly, twenty (20) 1 × 1 m2 quadrats of 60 samples were collected at different soil depths (0–3 cm, 3–6 cm, 6–9 cm) and were warm stratified at about 21–39 °C in a greenhouse for seedling outcome. A total of 97 undergrowth species were encountered aboveground, while a total of 18 plant species were distributed at 0–3 cm, 16 at 3–6 cm, and 8 at 6–9 cm seedling emergence. The results from the statistical analysis showed the observed differences among the soil depths from the seedling outcome are significant, and there is a strong dissimilarity between the seedling outcome and the undergrowth species. The undergrowth species pattern is more diverse, and the species richness is higher, which implies a stable community with little or no disturbance. Regrettably, some aging trees were still underrepresented, despite the undergrowth species richness and diversity. More so, the IUCN red list assessment showed that numerous plants, i.e., 34 plants out of 97 undergrowth species, fall into the category of Not Evaluated (NE), which showed that many plants in this typical forest are still going through IUCN evaluation. The current evaluation will assist the IUCN assessment and also help government agents in the conservation allotment of underrepresented aging trees in the protected forest. In the meantime, public education will be used to manage the unsustainable gathering of wild fruit and forest food in the buffer zone. This will be followed by support for home gardens as a means of preventing the overuse of aging tree fruit and plants throughout the ecosystem. It was advised that research be done in protected areas of the forest on soil depths suitable for seedling recruitment and soil seed banks potential that would support conservation action allocation.Item Reinstatement of Aloe mutans (Asphodelaceae subfam. Alooideae), a distinctive, endemic, maculate aloe from the central Limpopo province of South Africa(Magnolia Press, 2024-03-12) Smith, Gideon F.; Figueiredo, Estrela; Klopper, Ronell RenettUntil 1987, Aloe mutans (Asphodelaceae subfam. Alooideae) was accepted as a distinctive species of maculate aloe from South Africa’s Limpopo province. However, this species thereafter often has been included in the synonymy of A. greatheadii var. davyana. Recently, A. davyana was separated from A. greatheadii at the rank of species, which requires reconsideration of the taxonomic status of A. mutans. It is shown that A. mutans differs from A. davyana in several vegetative and reproductive morphological characters so warranting its recognition at the rank of species. Aloe mutans is therefore here reinstated as an accepted species. Both A. mutans and A. davyana are illustrated and an amplified description is provided for A. mutans.Item Petalidium namibense (Acanthaceae), a new species from Namibia(Magnolia Press, 2024-11-12) Swanepoel, Wessel; Van Wyk, Abraham Erasmus (Braam)Petalidium namibense, hitherto confused with P. englerianum, P. rossmannianum, and the widespread P. variabile, is here described as a new species. It is a range-restricted species, only known from the area to the southwest, west and northwest of Puros in the Kaokoveld Centre of Endemism, northwestern Namibia, where it grows at the base of rocky outcrops, on arid hillsides, and along ephemeral riverbeds and drainage lines. Diagnostic characters for P. namibense include the pale grey appearance of the plants, corky bark on older stems, vegetative parts with a dense white indumentum of relative long dendritic trichomes appearing lanate, flowers borne in short few-flowered dichasia, and bracteoles narrowly ovate. The flowers of P. namibense are distinctive in having the two upper corolla lobes discolorous, abaxially light brown, adaxially vermillion, without nectar guides, and connate towards the base for 25–40% of their length. The anterior lobe is adaxially magenta with two relative long, narrowly triangular yellow nectar guides. The two lateral lobes are adaxially vermillion, or distally magenta, grading to vermillion towards the throat, and lack conspicuous nectar guides. A comparison of key morphological features distinguishing P. namibense from P. sesfonteinense, its closest relative in appearance, as well as from P. englerianum, P. rossmannianum, and P. variabile, is provided. Based on IUCN Red List criteria, a provisional conservation assessment of Vulnerable (VU) is recommended for the new species.Item Petalidium etendekaense (Acanthaceae), a new species from Namibia, with notes on the taxonomic identity of P. glutinosum(Magnolia Press, 2024-02-01) Swanepoel, Wessel; Manzitto-Tripp, Erin A.; Dexter, Kyle G.; Van Wyk, Abraham Erasmus (Braam)Petalidium etendekaense, previously mistaken for P. glutinosum and P. variabile, is now described as a new species. The name P. pilosibracteolatum is considered synonymous with the older P. glutinosum, the latter of which is also lectotypified. The newly described species is currently only known from the vicinity of Bergsig and slightly further west towards the Skeleton Coast National Park in the Kaokoveld Centre of Endemism, northwestern Namibia. It typically grows on hillsides and along ephemeral riverbeds, primarily in soils derived from Etendeka Group basalt. Diagnostic characters for P. etendekaense include its tomentose-strigulose indumentum, the inflorescence main axis and secondary branches that invariably become spiny with age, and a corolla with an ovate front lobe that is longer than it is wide. Additionally, all lobes of the corolla exhibit similar colours, ranging from dark burgundy to carmine to pink towards the apices. A comparison of some morphological features is provided to differentiate Petalidium etendekaense from P. glutinosum and P. variabile. Based on the IUCN Red List categories and criteria, we conducted a conservation assessment, resulting in the new species being classified as of Least Concern (LC).Item Clarifying the placement of Trifolium capense in leobordea (Fabaceae)(Magnolia Press, 2024-01-24) Le Roux, M. Marianne; Klopper, Ronell Renett; Boatwright, James S.No abstract available.Item Cyphia deliae (Campanulaceae: Cyphioideae), a new species from South Africa and Eswatini(Magnolia Press, 2024-01-09) Steyn, Hester Maria; Van Wyk, Abraham Erasmus (Braam)Cyphia deliae, previously confused with C. bolusii, is described here as a new species. It is a range-restricted species known only from the Barberton Centre of Endemism, a biogeographical region that spans the border between South Africa and Eswatini. This species grows on rocky outcrops in montane grassland. Cyphia deliae can be differentiated from its morphologically most similar relative, C. bolusii, primarily by floral characters. A comparison of specific morphological features distinguishing Cyphia deliae from C. bolusii is provided. In accordance with IUCN Red List categories and criteria, a conservation assessment of Vulnerable B1ab(iii); C2a(i) is recommended for the new species.Item Aloe burgersfortensis (Asphodelaceae subfam. Alooideae): a distinctive, winter-flowering maculate aloe endemic to the southeastern Limpopo and northwestern Mpumalanga provinces of South Africa(Magnolia Press, 2024-02-01) Smith, Gideon F.; Figueiredo, Estrela; Klopper, Ronell RenettAloe burgersfortensis (Asphodelaceae subfam. Alooideae), which generally has been included in the synonymy of A. parvibracteata since 2000, is formally reinstated as an accepted species that is endemic to the southeastern Limpopo and northwestern Mpumalanga provinces of South Africa. Aloe burgersfortensis differs from A. parvibracteata in several vegetative and reproductive morphological characters so warranting its recognition at the rank of species; the differences are quantified and discussed. The typification of the name A. burgersfortensis is reinterpreted and corrected. Both A. burgersfortensis and A. parvibracteata are illustrated and an amplified description is provided for A. burgersfortensis.Item Plant community responses to climate change : the importance of ecological context dependencies(Wiley, 2025-03) Michalet, Richard; Dolezal, Jiri; Lenoir, Jonathan; Le Roux, Peter Christiaan; Rumpf, Sabine; Wipf, SonjaNo abstract available.Item Fine scale patterns and drivers of plant species richness on a sub-Antarctic island(Wiley, 2025-03) Tsamba, Joshua; Le Roux, Peter Christiaan; Pertierra, Luis R.; Kuhlase, Bongekile Sinenhlanhla Nontokozo; Greve, MichelleAIMS : Cold environments, such as polar systems, are highly vulnerable to global change drivers such as climate change and invasive species. Therefore, it is essential to assess what drives the diversity of native and invasive species in these systems. LOCATION : We investigated what drives native and alien plant species richness on sub-Antarctic Marion Island and determined the scale-dependence of these drivers. METHODS : Native and alien plant species richness was surveyed at “small” (1 m2) and “large” (9 m2) sampling grains. Difference in richness between the two sampling grains was calculated to assess how local turnover contributes to species assemblage. The factors driving richness at both grains, and the differences in richness between the two grains, were analysed using simultaneous auto-regressive models. Drivers related to energy and environmental heterogeneity were correlated with native richness, whilst drivers related to productivity were related to alien richness. RESULTS : Biotic interactions with a cushion plant facilitated native richness, but restricted alien richness at low elevations. Further, some drivers of richness depended on spatial grain. Native richness was positively related to northness at large, but not small grain size, suggesting that higher northness increases local turnover at a grain size > 1 m2. On the other hand, topographical wetness index (TWI) boosted native richness at small but not large grains, implying that competition for water limits coexistence at low TWI (i.e., low moisture availability) only at small grain. Differences in native species richness between large and small grain sizes were more pronounced at low elevations, suggesting higher compositional heterogeneity at low altitudes. CONCLUSIONS : Our study highlights that drivers of plant species richness in a polar ecosystem differ between native and alien plant species. Additionally, the effects of some drivers on richness differ between sampling grains, and considering these differences provides insight into drivers of local patterns of species assemblage.