Research Articles (Biodiversity and Conservation Biology)

Permanent URI for this collectionhttps://hdl.handle.net/10566/35

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A microplastic meal: a baseline assessment of microplastic polymer presence within manta-ray (Mobula alfredi) feeding grounds at D'Arros Island and the St. Joseph Atoll
(Elsevier Ltd, 2026) Choppy, Monik T; Duncan, Murray I.; Gordon, Nuette; Pouponeau, Dillys K; Bullock, Robert W; Grimmel, Henriette M V; Rajkaran, Anusha
Microplastic ingestion by reef manta rays ( Mobula alfredi ) is a threat to their health and population stability. Seychelles' outer islands are vital habitats for M. alfredi but nothing is known about marine microplastic pollution in the area. Using plankton tows from D'Arros Island and St. Joseph Atoll – a key aggregation site, we quantified microplastic polymer type and relative abundance from locations where reef manta rays were actively feeding. We found polybutylene terephthalate (PBT, 1079 particles, 66%) to be the most abundant polymer using our screening technique. A polymer concern assessment identified polyurethane (PU), polyacrylonitrile (PAN), polyvinyl chloride (PVC) and PBT as “Very High” concern polymers that warrant further attention. We find no significant relationship between total microplastic abundance and zooplankton biomass indicating M. alfredi does not ingest relatively greater quantities of MPs while feeding at this aggregation site.
An overview of current knowledge on microalgae and macrophytes in South African estuaries, highlighting progress made and future research directions
(Elsevier B.V., 2026) Adams, JB; Rajkaran, Anusha; Riddin, T
South Africa’s 3000 km coastline, 290 estuaries and high levels of biodiversity provide an outdoor laboratory for studies on microalgae and macrophytes. The history of botanical research on estuaries is presented, focusing on studies of primary producers, highlighting progress made since 2016. Published articles were organised in seven categories representing the dominant primary producers in estuaries. Research priorities were identified for each category based on the systematic review of literature from 2017 to January 2025, complemented by expert input on emerging trends and knowledge gaps. Invasive alien aquatic plants and forested wetlands (swamp forest) are emerging research themes. Early studies focussed on autecology and ecophysiology. More recently, research has addressed ecological status, drivers of biodiversity, provision of ecosystem services, responses to climate change and the restoration and management of Blue Carbon Ecosystems. Since 2016, 212 articles have been published on these emerging themes. In South Africa, we have a good understanding of primary producers as indicators of water quality changes in estuaries. Research has informed the implementation of Estuary Management Plans and the National Water Act, which guides estuary environmental flow requirements. Taxonomic studies on salt marsh plants to inform the National Biodiversity Assessment and using artificial intelligence and automation to provide real time monitoring of priority systems were identified as knowledge gaps. We have long term monitoring sites to measure responses to sea level rise, and to measure the growth and survival of mangroves across biogeographic zones. However, a growing concern is personal safety and security that impacts field work, constraining ecological research and the maintenance of long-term datasets that are needed to track future responses to global pressures. We are well positioned to inform global research and policy agendas such as the Kunming-Montreal Global Biodiversity Framework that aims to expand protection and restoration of coastal ecosystems to 30 % by 2030.
Grazing lawns affect vegetation composition and diversity of the endangered silcrete fynbos in the Bontebok National Park
(Elsevier B.V., 2026) Grootboom, Claire; Samuels, Igshaan; Engelbrecht, Adriaan
Grazing animals affect their environment. The Bontebok National Park hosts a number of hooved animals, which causes alterations to the habitat, resulting in the establishment of grazing lawns. The proliferation of these lawns may pose a threat to the intact natural vegetation occurring in the park. The aim of this study was to determine how the existence of these lawns impact the endangered Swellendam Silcrete Fynbos vegetation in the park. Sites were identified in three categories in the park, namely lawns, ecotones, and natural vegetation areas. Vegetation was sampled to assess the species diversity and composition in the three zones, and soils were collected to investigate physio-chemical parameters. Species diversity indices were calculated for the vegetation that were sampled. Soil physico-chemical parameters were used to generate a PCA and box plots for comparison between the different zones sampled in the BNP. Dendrograms were created to show similarities in plant species across the various sites that were sampled. The BNP is dominated by shrubs and grasses, with compositional shifts taking place from the natural vegetation transitioning to lawns. Plant assemblages showed a noticeable decrease in diversity in larger lawns, and the greatest diversity was seen in the ecotones. Soils found in the lawns had higher amounts of macro- and micronutrients, as well as heavy metals. Medium and large lawns also had higher pH levels causing soils to become more basic. These factors all play a role in contributing to the composition shift of vegetation in the intact vegetation from being dominated by shrubs to lower growing vegetation such as grasses and forbs in the lawns. Grazing can have dire impacts on vegetation diversity and can pose a major threat to the endangered vegetation and soil physiochemical parameters in the park. Park management should monitor grazing animal densities adaptively to reduce the spread of lawns and loss of biodiversity in the adjacent vegetation assemblages.
An updated classification of growth forms in non-geniculate coralline algae (Corallinophycidae, Rhodophyta)
(John Wiley and Sons Inc, 2026) Maneveldt, Gavin W; Brodie, Juliet; Calderon, Martha S
The current challenge of defining growth forms in the non-geniculate coralline red algae was addressed. Since the 19th century, those who have worked on this large and globally distributed group of algae have tried to summarize and systematically describe their growth forms. This effort resulted in a plethora of terms, which could sometimes be confusing, overlapping, and difficult to apply in the field. We reviewed the past literature to provide a coherent key to the non-geniculate coralline growth forms, incorporating the latest observations. Our revision expands the 10 currently recognized growth forms (unconsolidated, encrusting, warty, lumpy, fruticose, discoid, layered, foliose, ribbon-like, and arborescent) by redefining some of them, by reintroducing the columnar growth form, and by adding two new growth forms—convoluted and imbricate—to include recently documented specimens. This updated and refined tool better encompasses the diverse external morphologies of non-geniculate corallines. The goal was to facilitate taxonomic descriptions and to support ecological studies of non-geniculate corallines given the extreme difficulty of identifying species using only external characters.
Woody vegetation characteristics of selected rangelands along an aridity gradient in Namibia: implications for rangeland management
(MDPI, 2025) Inman, Emilia N; Samuels, Igshaan; Tsvuura, Zivanai; Angula, Margaret; Nakanyala, Jesaya
Rangelands form the ecological and economic backbone of Namibia, yet the woody plant dynamics that sustain these landscapes remain sporadically quantified across the semi-arid interior. We investigated the characteristics (stand structure, regeneration, richness, diversity, composition, ecological importance, and indicator species) of woody communities along a pronounced south-to-north rainfall gradient (85–346 mm yr−1) at five representative sites: Warmbad, Gibeon, Otjimbingwe, Ovitoto, and Sesfontein. Field sampling combined point-centered quarter surveys (10 points site−1) and belt transects (15 plots site−1). The basal area increased almost ten-fold along the gradient (0.4–3.4 m2 ha−1). Principal Coordinates Analysis (PCoA) arranged plots in near-perfect rainfall order, and Permutational Multivariate Analysis of Variance (PERMANOVA) confirmed significant site differences (F3,56 = 9.1, p < 0.001). Nanophanerophytes dominated hyper-arid zones, while microphanerophytes appeared progressively with increasing rainfall. Mean annual precipitation explained 45% of the variance in mean height and 34% of Shannon diversity but only 5% of stem density. Indicator value analysis highlighted Montinia caryophyllacea for Warmbad (IndVal = 100), Rhigozum trichotomum (75.8) for Gibeon, Senegalia senegal (72.6) for Otjimbingwe, and Senegalia mellifera (97.3) for Ovitoto. Rainfall significantly influences woody structure and diversity; however, other factors also modulate density and regeneration dynamics. This quantitative baseline can serve as a practical toolkit for designing site-specific management strategies across Namibia’s aridity gradient.
Land cover shifts strain resource nexus in Southern Africa: evidence from Malawi
(Frontiers Media SA, 2025) O’Farrell, Patrick John; Makwinja, Yamikani Harry; Kimengsi, Jude Ndzifon
Landscapes in southern Africa are subjected to significant dynamics related to Land Cover Change (LCC). While there is abundant research on Land Cover Trajectories (LCT), more comprehensive studies are still needed to determine the extent to which these changes reshape the Water-Energy-Food-Climate (WEFC) Nexus. We employed an explanatory sequential mixed-methods approach in Malawi using Case studies of Blantyre and Lilongwe districts to 1 explore trends in LCC from 1994 to 2024, and 2 analyse the effects of land cover trends on the WEFC Nexus. This approach involved conducting a quantitative analysis of Landsat images using ArcGIS software to determine the LCC and applying the Mann-Kendall statistical analysis test to identify trends in key land cover classes and associated resources. Qualitative data were gathered using ethnographic techniques, focus group discussions, key informant interviews, and expert interviews. These were analysed through deductive content analysis to provide complementary evidence. The analysis reveals 1 a dynamic land cover transformation characterised by a significant decline in forest cover, cropland expansion, and urbanisation. 2 LCC directions that weaken WEFC Nexus. Declining water productivity and increasing water stress are diminishing hydropower generation capacity and degrading ecosystem integrity, thereby threatening regional water and energy security. Concurrently, agricultural intensification has failed to ameliorate food insecurity within local communities. The study reveals significant inefficiencies in resource allocation and reflects profound underlying socioeconomic disparities. It offers valuable theoretical and policy implications for the Resource Nexus in southern Africa. It also highlights the significance of the WEFC Nexus in Malawi and serves as a pertinent example for other southern African nations facing similar challenges. It advocates for ongoing research and adaptive management strategies to address the interdependencies of these resources, supporting Nature-positive sustainable development and enhancing resilience against socio-environmental changes.
Value archetypes in future scenarios: the role of scenario co-designers
(Resilience Alliance, 2025) O'Farrell, Patrick; Harmáčková, Zuzana; Eisenack, Klaus
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) relies on future scenarios in its assessments of global social-ecological systems. Scenarios explicitly or implicitly embed normative positions (e.g., values for nature, nature’s contributions to people, good quality of life). Such scenario values shape how scenario narratives evolve, e.g. through driving forces, framings, or ways how decisions are legitimized within a given scenario. Initial research in futures studies has examined how scenario values depend on whose voices are included in scenario co-design. However, less attention has been paid so far to explicitly assessing the extent to which scenario values are associated with different types of scenario co-designers. Our paper expands this knowledge with a set of novel analyses building on the comprehensive review of scenarios in the IPBES values assessment. To this end, we conducted a formal archetype analysis of 257 scenarios assessed in the IPBES values assessment to identify re-appearing archetypal configurations of values and their link to the actors involved as scenario co-designers. The results show that scenarios valuing nature for itself and its benefits to societal well-being were co-designed by experts and academics less frequently than expected under the assumption of stochastic independence; on the contrary, such scenarios were co-designed more frequently than expected by governmental and community actors. The paper illustrates how archetype analysis can contribute to the validation and further development of scientific knowledge feeding into science-policy assessments. The findings are important to acknowledge how scenarios express and possibly re-enforce peoples’ normative positions, and what role values might play when scenarios get translated into realworld decisions and actions.
Diatom colonisation and biofilm metal bioaccumulation: can indigenous knowledge systems aid the ecological engineering of urban coastlines?
(Elsevier B.V, 2025) Cotiyane-Pondo, Phumlile; Ndaba, Jabulani; Human, Lucienne
Marine engineered structures alter the coastal ecosystems' functionality, replacing natural substrates with flat surfaces, often negatively impacting biodiversity. While providing coastal protection, artificial structures can hinder the initial colonisation by biofilm and the recruitment of coastal species. Greening the grey infrastructure through nature-based interventions is increasingly used to enhance biodiversity in artificial structures. This study explores the potential of the sedge Cyperus textilis and its Indigenous Knowledge applications as a substrate for coastal eco-engineering at an urbanised site on the southeast coast of South Africa. Diatom succession and metal bioaccumulation on the deployed trial-version designs (imizi structures) were monitored for a month, with samples collected at six, twelve, twenty-four, seventy-two hours, one and two weeks, and one month after deployment. Water quality, including dissolved nutrients and metal concentrations, were assessed near the substrates. Findings indicated that diatom colonisation occurred within twelve hours, with initial species including Fragilaria pulchella, Neofragilaria nicobarica, Navicula sp. and Grammatophora undulata, followed by a significant increase (4.6 times) in species diversity from 5 to 23 diatoms after one week. Metal bioaccumulation of aluminium, iron, zinc, manganese and arsenic was higher in the biofilm developing on the substrate compared to its surrounding environment (imizi substrate and water), suggesting the potential bioremediating capabilities of the biofilm on the nature-based material. These findings indicate the potential suitability of using Indigenous Knowledge-based materials for coastal eco-engineering practices as promoters of primary productivity, with the added potential of the plant C. textilis for bioremediation of toxic metals such as arsenic.
Vocal repertoire and acoustic cues to individual identity in the Northern Rockhopper penguin (Eudyptes moseleyi)
(Taylor and Francis Ltd., 2026) Ludynia, Katrin; Turone, Vittoria; Zanoli, Anna
Northern Rockhopper penguins (Eudyptes moseleyi) are highly vocal seabirds. However, detailed descriptions of their vocal repertoire are currently unavailable. Here, we studied the vocal behaviour of this species and assessed the presence of acoustic cues of individuality across different vocal types. We collected audio and video recordings from an ex-situ colony at the Two Oceans Aquarium (Cape Town, South Africa) consisting of wild rescued individuals and their offspring. We combined the visual inspection of spectrograms with spectro-temporal acoustic analyses based on a source-filter theory approach. Our results showed that the vocal repertoire of the Northern Rockhopper penguin is made of three discrete vocal types: agonistic calls, uttered during agonistic interactions, contact calls, produced to maintain acoustic contact among group members when visually isolated, and ecstatic display songs, mediating territorial defence and mate attraction. Moreover, we demonstrated that all vocal types encode acoustic cues to the individual identity of the emitter. Studying the vocal repertoire of penguins is crucial for a deeper understanding of their social behaviour and may ultimately contribute to the conservation of this endangered seabird.
Concentration of chemical elements in dry mass of Pontederia crassipes Mart. for use as organic fertilizer in small-scale crops
(Universidad Autonoma Metropolitana, 2025) Naidoo, Sershen; Hernández-Fernández, Leslie; Carlos Lorenzo Feijoo, José
Background: the increasing demand and production costs of inorganic fertilizers motivate researchers to explore new ways to obtain organic fertilizers. Pontederia crassipes Mart., is an invasive aquatic plant that grows in a freshwater lagoon (La Turbina), in Ciego de Ávila, Cuba. It is extracted from the water and deposited on the shores of the lagoon, affecting the aesthetic value of the site. Objective: to determine the concentration of chemical elements in the dry mass of P. crassipes (in its floating and emerging growth condition), to recommend its possible use as organic fertilizer or mixed substrate in small area crops. Method: for the analysis of most of the chemical elements, both in the lagoon water and in the dry mass of P. crassipes, inductively coupled plasma optical emission spectrometry was used. Results: the water of a lagoon was characterized by high concentration of Ca. In the dry mass of P. crassipes (floating and emergent), Ca, N, and K had the highest concentrations (mg g-1), followed by Na and Al. Heavy metals had concentrations below the maximum permissible limits for organic fertilizers and substratum of the crop. The eight chemical elements quantified in the lagoon water (Ca, Cu, K, Mg, Na, P, S, and Zn) showed bioconcentration in P. crassipes (floating). Seven chemical elements showed translocation in P. crassipes (B, Ca, K, N, Na, and Sr). Conclusions: The dry mass of P. crassipes can be used as organic fertilizer or as a mixed substrate for small-scale crops. Floating P. crassipes can phytostabilize and phytoextract chemical elements in the La Turbina artificial freshwater lagoon.
A century later: discovery of a second Podospongia species offshore from the Table Mountain National Park MPA, South Africa
(Cambridge University Press, 2026) Samaai, Toufiek
A new sponge species (Demospongiae: Poecilosclerida: Podospongiidae) is described offshore from the Cape of Good Hope, on the southern edge of the Table Mountain National Park marine protected area. Podospongia capensis sp. nov. is compared to Podospongia natalensis, described by Kirkpatrick (1903) from the east coast of South Africa, as well as to all other Podospongia species described to date. The new species differs from P. natalensis in having a shorter, thicker stalk, lacking anisostrongyles as megascleres, and possessing a second category of large symmetrical aciculospinorhabds microcleres that are present in P. natalensis. Additionally, P. natalensis has larger oxeas and styles than those found in P. capensis sp. nov. Furthermore, the two species are geographically separated, with P. natalensis described from the Natal ecoregion, while P. capensis sp. nov. is described from the Southern Benguela ecoregion. The new species primarily differs from other congeners in external morphology and size of the oxeas and styles.
Heuweltjies as within-paddock indicators of veld condition in the Succulent Karoo: vegetation contrasts between mound and intermound habitats
(Elsevier B V, 2026) Samuels, Igshaan; Gallant, Luke; Inman, Emilia N.
Heuweltjies (microtopographic earthen mounds) are conspicuous across South Africa's semi-arid, winter-rainfall rangelands, yet their value as field-ready indicators of veld condition is under-tested. This study examines the suitability of heuweltjies as indicators of veld condition within paddocks in the semi-arid Succulent Karoo. We utilized a spatially explicit paired sampling design, comparing vegetation attributes on 16 mounds with adjacent intermound plots (the matrix), in the Ebenhaeser communal rangelands. We focused on operational diagnostics, which are repeatable, management-sensitive metrics derived from life-form balances, growth-form structure, and palatability-weighted abundance. Statistical comparisons utilized Generalized Estimating Equations (GEE) to ensure robust inference by accounting for the non-independence inherent in the paired plot design. Mound habitats consistently showed a strong utilization signal, characterized by significantly higher counts of palatable individuals, as well as high herb richness and Shannon diversity. This confirms the ecological function of heuweltjies as resource islands that concentrate desirable forage. Annual plants exhibited significantly higher abundance and cover on mounds, reflecting their sensitivity to the localized nutrient enrichment and disturbance inherent in these resource islands. Succulent shrubs (a key forage group) were significantly larger on mounds, yet grasses were more abundant on the intermound matrix, highlighting a competitive trade-off possibly driven by higher mound alkalinity or shrub competition. These results validate the inherent mound–intermound contrast as a robust, low-cost indicator framework. Formalizing metrics such as palatable plant count difference and annual proportion provides local managers with repeatable, management-relevant signals necessary for setting accurate utilization thresholds, thus improving the performance of broader veld condition assessments.
Revealing hidden diversity: new latrunculia and Iophon species porifera, demospongiae, poecilosclerida) from the continental shelf of the Namaqua ecoregion benguela ecosystem along with a range extension of latrunculia aciculatrunculia biformis
(Cambridge University Press, 2026) Samaai, Toufiek; Payne, Robyn Pauline; Kamwi, Blessing
Four new species of Poecilosclerida (Porifera, Demospongiae) assigned to the genera Latrunculia and Iophon are described from South Africa and Namibia, located in the Namaqua ecoregion. The Porifera occurring along the continental shelf within this ecoregion are relatively well-known, with 76 species formally described in previous literature. Of these, 35 species belong to the Order Poecilosclerida. Additionally, Latrunculia (Aciculatrunculia) biformis is reported from the continental shelf on the west coast of South Africa, extending its range further northwards into the South Atlantic. DNA barcoding and molecular phylogenetic analyses were employed to ensure accurate taxonomic assignment and designation of new species.
Habitat modification by grazing lawns reduces soil mite diversity in a South African National Park
(John Wiley and Sons Inc, 2026) Grootboom, Claire; Samuels, Igshaan; Engelbrecht, Adriaan
Soil mesofauna are an integral part of the functioning of an ecosystem. They are relatively small in body size, occur in varying habitats and operate in a range of ecological niches. Soil mites are quite sensitive to changes in their environment and contribute to several important ecosystem services in their environments. This investigation aimed to determine how soil mite communities change in and around lawns in the Bontebok National Park (BNP). Sites that were sampled were categorised into lawns, ecotones and natural vegetation. Soils were collected to analyse physio-chemical parameters and to evaluate species composition of soil dwelling mites. Shannon and Simpson indices were used to determine species diversity of the different zones sampled and soil properties were used to generate PCAs and boxplots. There were changes in mite populations and community structure that were noticed in and around grazing lawns in the park, with a great reduction in diversity in lawns and the highest diversity seen in the ecotones. Lawns had higher proportions of macro and micronutrients, in addition to higher heavy metal content, which affected the oribatid mite populations inhabiting those areas. The establishment of lawns in the BNP had a negative impact on the mite populations in the park. This can be a major concern to soil mite communities in the park as they act as a vital component of the ecosystem, and contribute importantly to the overall functioning of their environment.
Distribution and status of reptile species in south-eastern Zimbabwe
(Taylor and Francis Ltd., 2025) van Wyk, Kurt; Maritz, Bryan; Clegg, Bruce William
While the loss of biodiversity in response to anthropogenic drivers is well documented, reptiles are rarely prioritised in global conservation efforts. Although more than 20% of all reptile species are currently listed as threatened, and a growing body of evidence highlights the sensitivity of reptiles to habitat change, basic information on the distribution, natural history, and regional conservation status of African reptiles remains sparse. Habitat loss through agricultural land-use change is regarded as the primary threat to global biodiversity and to southern African reptiles in particular. Arid and semi-arid ecoregions in southern Africa have been identified as areas of global conservation priority for reptiles. However, the status of Zimbabwe’s reptiles remains largely unknown. Limited resources and more urgent concerns have hampered what Zimbabwe has been able to achieve with respect to international conservation initiatives. Furthermore, the ecological impacts of recent, wide-scale land-use change in the country have received little attention. As legacies of historical land-use change are acknowledged as determinants of current landscape ecology, addressing the long-term effects of land-use change on Zimbabwe’s reptiles is crucial for effective conservation and management. Here we provide a complete account of the reptile taxa recorded in south-eastern Zimbabwe. We discuss sources of spatial and temporal bias in the occurrence dataset and highlight the importance of the region’s protected area network for conserving reptile diversity. Our study increases the number of published reptile occurrence records from the region by an estimated 285%
Vulnerability of marine megafauna to global at-sea anthropogenic threats
(John Wiley and Sons Inc, 2026) Waller, Lauren; VanCompernolle, Michelle; Morris, Juliet
Marine megafauna species are affected by a wide range of anthropogenic threats. To evaluate the risk of such threats, species’ vulnerability to each threat must first be determined. We build on the existing threats classification scheme and ranking system of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species by assessing the vulnerability of 256 marine megafauna species to 23 at-sea threats. The threats we considered included individual fishing gear types, climate-change-related subthreats not previously assessed, and threats associated with coastal impacts and maritime disturbances. Our ratings resulted in 70 species having high vulnerability (v > 0.778 out of 1) to at least 1 threat, primarily drifting longlines, temperature extremes, or fixed gear. These 3 threats were also considered to have the most severe effects (i.e., steepest population declines). Overall, temperature extremes and plastics and other solid waste were rated as affecting the largest proportion of populations. Penguins, pinnipeds, and polar bears had the highest vulnerability to temperature extremes. Bony fishes had the highest vulnerability to drifting longlines and plastics and other solid waste; pelagic cetaceans to 4 maritime disturbance threats; elasmobranchs to 5 fishing threats; and flying birds to drifting longlines and 2 maritime disturbance threats. Sirenians and turtles had the highest vulnerability to at least one threat from all 4 categories. Despite not necessarily having severe effects for most taxonomic groups, temperature extremes were rated among the top threats for all taxa except bony fishes. The vulnerability scores we provide are an important first step in estimating the risk of threats to marine megafauna. Importantly, they help differentiate scope from severity, which is key to identifying threats that should be prioritized for mitigation.
Editorial expression of concern: PICSI vs. MACS for abnormal sperm DNA fragmentation ICSI cases: a prospective randomized trial
(Springer, 2025) Henkel, Ralf; Hasanen, Eman; Elqusi, Khaled
The Editor-in-Chief is issuing this Editorial Expression of Concern to alert readers that concerns have been raised about the data presented in this article. Specifically, Table 1 presents the demographic information about the PICSI arm of this study as a decimal percentage, even though such percentages are not possible for a cohort of 200. The authors have stated that the reason for this is that not all participants provide full information about all demographic characteristics, so in each case the values are a percentage of a number that is less than 200. However, the authors have not been able to provide patient-level data due to the confidentiality statement that was signed by participants included in this study, and so the Editor-in-Chief has not been able to confirm this explanation or to verify the number of participants who failed to return information for each demographic characteristic. Readers are advised to interpret the data presented in this article with caution
Identifying essential chemical descriptors for auxins, cytokinins, and gibberellins using principal component analysis
(Springer, 2025) Sershen Naidoo; Quintana‑Zaez Julio César; Gómez Daviel
Auxins, cytokinins, and gibberellins are plant growth regulators (PGRs) that significantly influence plant growth and development. Investigating their molecular descriptors is vital for understanding how these PGRs work in intricate networks, influencing each other’s activity and responding to environmental cues, but this can be challenging given that PGRs often mimic or interact with naturally occurring plant growth regulators, which are themselves a complex group of chemicals with diverse structures and functions. This motivated the present study, which evaluated the effectiveness of principal component analysis (PCA), a statistical method renowned for reducing the dimensionality of intricate datasets, in identifying the key molecular descriptors that distinguish these three plant growth regulators. A total of 212 molecular descriptors were previously determined. Using PCA, the study identified critical chemical descriptors for auxins, cytokinins, and gibberellins, including ring count, presence of secondary alcohols, and terminal primary C (sp2) structures. Importantly, the study also confirmed the value of PCA in identifying key molecular descriptors for PGRs in studies focused on understanding their mechanism(s) of action. This paper introduced a novel methodological approach that contributes meaningfully to the understanding of PGRs.
Evaluation of risks of oil contamination in endangered seabirds in Algoa Bay, South Africa, linked to ship-to-ship bunkering and anthropogenic maritime activities
(Elsevier Ltd, 2026) Ludynia, Katrin; Stassen, Monica; Fearon, Giles
This study evaluates the ecological risks of oil contamination to endangered seabirds in Algoa Bay, South Africa, linked to ship-to-ship (STS) bunkering activities and other anthropogenic maritime activities. Between 2016 and 2024, 378 oiled seabirds—primarily African penguins and Cape gannets—were admitted to rehabilitation centres, with over half linked to STS-related spills. An established modelling system was used to model the trajectory of oil from the MV Chrysanthi S spill in 2019 (400 L of Heavy Fuel Oil), using the simulated environmental conditions at the time of the spill. The model predicted that core foraging areas would have remained exposed to oil for about a week after the spill and that birds would have been found and rescued days after their contamination. Probabilistic modelling of 200 spill scenarios revealed high likelihoods of shoreline oiling and persistent surface contamination, especially during austral winter, when oil is more likely to reach Bird Island's seabird foraging areas. Spills from the offshore extent of anchorage area 2 are more likely to result in impacts on the seabird foraging areas. The model indicates that a high degree of conservatism is required when selecting ecological thresholds for impacts on African penguins, given the relatively high observed impacts despite low modelled surface thicknesses from a 400 L spill. These findings underscore the urgent need for stricter regulation of offshore bunkering in ecologically sensitive areas and improved preparedness for wildlife rescue and rehabilitation, especially in an area of such high biodiversity as Algoa Bay.
A place-based assessment of biodiversity intactness in sub-Saharan Africa
(Nature Research, 2025) Maritz, Bryan; Clements, Hayley S; Biggs, Reinette
Maintaining biodiversity is central to the sustainable development agenda1. However, a lack of context-specific biodiversity information at policy-relevant scales has posed major limitations to decision-makers2,3. To address this challenge, we undertook a comprehensive assessment of the biodiversity intactness of sub-Saharan Africa4 using place-based knowledge of 200 African biodiversity experts5. We estimate that the region has on average lost 24% of its pre-colonial and pre-industrial faunal and floral population abundances, ranging from losses of <20% for disturbance-adapted herbaceous plants to 80% for some large mammals. Rwanda and Nigeria are the least intact (<55%), whereas Namibia and Botswana are the most intact (>85%). Notably, most remaining organisms occur in unprotected, relatively untransformed rangelands and natural forests. Losses in biodiversity intactness in the worst-affected biomes are driven by land transformation into cropland in grasslands and fynbos (Mediterranean-type ecosystems), by non-agricultural degradation in forests and by a combination of the two drivers in savannas. This assessment provides decision-makers with multifaceted, contextually appropriate and policy-relevant information on the state of biodiversity in an understudied region of the world. Our approach could be used in other regions, including better-studied localities, to integrate contextual, place-based knowledge into multiscale assessments of biodiversity status and impacts.

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