Research Articles (Biodiversity and Conservation Biology)

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

Browse

Now showing 1 - 20 of 325

Global plastic governance approaches and policy pathways for strengthening South Africa's circular plastics economy
(Elsevier B.V., 2026) Nicolaides S.G.; Rajkaran A; Fenton D.H
Plastic pollution has intensified into a major global environmental crisis, with single-use plastics (SUPs) and microplastics accumulating across terrestrial, freshwater, and marine systems. Although many countries have adopted bans, levies, and Extended Producer Responsibility (EPR) schemes, their effectiveness varies widely due to differences in governance capacity, enforcement, and socio-economic context. South Africa faces escalating plastic waste generation, weak municipal implementation, and limited regulation of microplastics, despite possessing a comprehensive legislative framework under the National Environmental Management: Waste Act and the National Waste Management Strategy. Addressing this gap between policy ambition and practical outcomes requires a clearer understanding of the policy instruments that have succeeded elsewhere. This article undertakes a comparative analysis of two contrasting but globally successful models, Rwanda and Germany, situated within a broader global benchmarking of plastic policy instruments to extract policy lessons relevant to South Africa. Rwanda demonstrates how strict bans, civic mobilisation through Umuganda, and strong enforcement can drive behavioural change in low-income contexts. Germany, by contrast, exemplifies an advanced circular economy model built on deposit-return schemes (DRS), eco-modulated EPR fees, and extensive recycling infrastructure. Drawing on secondary literature, legal instruments, and international benchmarks, the article identifies key principles applicable to South Africa: aligning regulatory bans with public education, ring-fencing EPR and levy revenues, strengthening municipal capacity, and formally integrating informal waste pickers into the value chain. The analysis concludes that while no single model is universally transferable, Rwanda and Germany offer foundational insights for designing just and circular plastic governance frameworks tailored to South Africa's socio-economic and institutional realities.
Orthodox Christian teaching on eco-theology, psychological and legal facets, and the crisis of microplastic pollution in the World’s Oceans
(Africa Journals, 2026) Nicolaides S.G.; Nicolaides A.G.; Nicolaides A.C
Microplastic pollution constitutes one of the most inescapable and tenacious threats to marine ecosystems, with profound consequences for biodiversity, food security, and human health. Scientific research has established that microplastics are disseminated throughout ocean systems - from surface waters to deep-sea sediments - where they disturb ecological processes and bioaccumulate within marine food webs. Despite the growing body of empirical evidence, responses to microplastic pollution persist as inadequate, suggesting that the crisis is not simply technical but especially ethical and cultural in nature. This article employs an eco-theological framework to examine microplastic pollution as both an environmental and a moral and ethical failure. Drawing on contemporary marine science and theological ethics, the paper argues that microplastic pollution reflects a breakdown in humanity’s understanding of creation, stewardship, and interconnectedness. Eco-theology offers a normative lens that affirms the intrinsic value of creation, highlights environmental justice concerns, and motivates transformative action. Ocean pollution is significant and poses serious threats to human health and well-being and is distressful to most people causing psychological disturbance in some cases. Marine pollution in South Africa raises serious legal issues despite a strong regulatory framework. From a legal perspective, using South Africa as an example, the country is party to international instruments. Domestic laws are however fragmented and lead to jurisdictional gaps and blurred institutional accountability. Proving liability and obtaining compensation is problematic. Marine pollution also threatens constitutional environmental rights under section 24 of the Constitution. From a legal perspective, this study argues that South African law and Orthodox Christianity embody corresponding forms of social capital. The former being institutional and rights-based, the latter relational and ecclesial. Collectively, they offer different but intersecting responses to notions of societal care. When viewed through the lens of social capital, South African law and Orthodox Christianity emerge as individual yet complementary reactions to societal care. The law seeks to institutionalize dignity and inclusion through rights-based mechanisms, while Orthodox ecclesial life fosters relational networks of care grounded in faith and communion. In a society such as South Africa, marked by disparity and social division, the interaction between these frameworks propositions a richer and more holistic reaction to social strain than either could supply alone. By integrating scientific analysis, psychological impacts, legal stances and theological reflection, this interdisciplinary study contributes to environmental ethics scholarship and underscores the relevance of eco-theology in addressing the global crisis of ocean degradation. The Eastern Orthodox Church approaches ecological concerns not as a secular afterthought, but as an integral expression of its faith, worship, and understanding of creation. For Orthodoxy, ecology is grounded in theology, the liturgical life, and a holistic Christian vision of humanity’s vocation within God’s Creation. According to the Church’s teaching, care for the natural world is rooted in Creation as a gift from God, the Eucharistic and ascetic ethos of the Church, and the moral transformation of the human heart. This article also explores these themes, showing how the Orthodox Church tradition situates ecological responsibility within its core doctrine and spiritual practices.
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 Ian; 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 B.; Rajkaran, Anusha; Riddin, Taryn
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.
Physico-chemical variables influencing the distribution and abundance of macroinvertebrates in salt marsh habitats of the Berg River Estuary, South Africa
(National Inquiry Services Centre Ltd, 2025-04-25) Rajkaran A.; Mngomezulu N.T.; Peer N.
Macroinvertebrates such as snails and crabs influence aspects of salt marsh structure and function through herbivory and bioturbation. However, the effects of physico-chemical variables and habitat composition on their abundance and distribution remain underexplored. This study examined the influence of environmental factors on snail and crab populations across salt marsh habitats in the Berg River Estuary on the west coast of South Africa, hypothesising greater abundance in the intertidal than in the supratidal zone, driven by salinity and elevation. Snail and crab abundance were assessed using manual counts in triplicate quadrats (10 × 10 cm for snails; 25 × 25 cm for crab burrows) across six transects. Physicochemical variables of sediment and groundwater were also analysed. Six snail species (Davisassiminea sp. 1, Davisassiminea sp. 2, D. capensis, D. globulus, Afrolittorina africana and Melanoides tuberculata) and one crab species (Hymenosoma orbiculare) were recorded. Crab burrow density differed significantly between habitats, with the highest abundance at creek edges (85.37 burrows m-2) and lowest in supratidal habitat (8.57 burrows m-2). Snail richness and abundance declined with elevation; Davisassiminea sp. 2 and D. capensis occurred only at creek edges. Habitat and environmental variables explained 32% of the variation in macroinvertebrate abundance, with sediment conductivity and organic content being key predictors. Generalised linear models indicated that species richness declined with increasing sediment redox potential (t = −2.25, p = 0.025), organic matter (t = −2.07, p = 0.040) and clay content (t = −3.07, p = 0.003). These findings highlight the influence of local environmental conditions in shaping and predicting species distributions under a changing climate.
Daily herd movements across the wet and dry season in the semi-arid communal rangelands of Namaqualand, South Africa
(Taylor and Francis Ltd., 2026) Tapela, Mbongeni Henderson; Igshaan Samuels, Mogamat; Cupido, Clement F.; Finca, Andiswa; Zondani, Thantaswa C.; Engelbrecht, Adriaan
The role of indigenous grazing management practices in sustainable natural resource use has been widely identified andrecognised in the literature. However, the grazing management practices of Nama pastoralists in the semi-arid regionsin Namaqualand in South Africa have not been adequately studied in terms of GPS-based seasonal grazing distribution.This study aimed to assess the seasonal livestock grazing distributional patterns across three communal rangelandsin Namaqualand using GPS collars. The objectives were to: (1) generate grazing distributional maps to identify patternsof seasonal rangeland use, (2) compare area covered at different grazing intensities of livestock between seasons,(3) delineate different grazing zones at different times of day, and (4) contrast seasonal differences within these grazingzones regarding grazing activity. CatLog GPS collars were mounted on livestock and T-LoCoH R package and GoogleEarth were used to generate grazing distribution maps showing areas most and least frequently used by livestock anddaily movement patterns. The results showed that Namaqualand herds grazed only a small proportion (21.1%) of theirmean home range (809.6 ± 76.2 ha) at high and moderate grazing intensities, regardless of season, corresponding toareas of 48.1 ± 13.5 ha and 287.7 ± 41.60 ha, respectively. In the wet season, herds used a 16.8% larger area than inthe dry season. The area associated with high grazing densities was significantly smaller than areas grazed at lowergrazing pressure. No significant differences in mean area associated with seasonal variation within each level ofgrazing suggests herders are not seasonally altering areas associated with high grazing intensity, which are sometimesassociated with permanent water sources. It is also likely that herders are concerned about ensuring their livestockhave sustained access to optimal forage sources by avoiding other flocks using the same areas. Grazing activity isindirectly proportional to grazing speed. Grazing activity is lower in the herded zones (the morning–excitement/appetitemoderation zone and the early afternoon–target zone, mean speed = 0.955 ± 0.006 km h−1) than when in an unherdedzone (late afternoon–late afternoon meal, mean speed = 0.852 ± 0.010 km h−1). Mean distance travelled daily by herds inthe herded zones was greatest (4.773 ± 0.029 km). In the wet season (7.365 ± 0.055 km) and a greater area was covereddaily (10.6 ± 1.2 ha) as resources become more abundant relative to the dry season. This suggests that indigenousherding practices in Namaqualand require ecologically aware decision-making processes associated with effectiveresource use. Contemporary grazing management policies should be more inclusive of indigenous management asaspects of holistic grazing management have been embedded in these practices for centuries.
Daily Herd Movements Across The Wet And Dry Season In The Semi-Arid Communal Rangelands Of Namaqualand, South Africa
(Taylor and Francis Ltd, 2026) Tapela M.H.; Engelbrecht A.; Zondani T.C.
The role of indigenous grazing management practices in sustainable natural resource use has been widely identified and recognised in the literature. However, the grazing management practices of Nama pastoralists in the semi-arid regions in Namaqualand in South Africa have not been adequately studied in terms of GPS-based seasonal grazing distribution. This study aimed to assess the seasonal livestock grazing distributional patterns across three communal rangelands in Namaqualand using GPS collars. The objectives were to: (1) generate grazing distributional maps to identify patterns of seasonal rangeland use, (2) compare area covered at different grazing intensities of livestock between seasons, (3) delineate different grazing zones at different times of day, and (4) contrast seasonal differences within these grazing zones regarding grazing activity. CatLog GPS collars were mounted on livestock and T-LoCoH R package and Google Earth were used to generate grazing distribution maps showing areas most and least frequently used by livestock and daily movement patterns. The results showed that Namaqualand herds grazed only a small proportion (21.1%) of their mean home range (809.6 ± 76.2 ha) at high and moderate grazing intensities, regardless of season, corresponding to areas of 48.1 ± 13.5 ha and 287.7 ± 41.60 ha, respectively. In the wet season, herds used a 16.8% larger area than in the dry season. The area associated with high grazing densities was significantly smaller than areas grazed at lower grazing pressure. No significant differences in mean area associated with seasonal variation within each level of grazing suggests herders are not seasonally altering areas associated with high grazing intensity, which are sometimes associated with permanent water sources. It is also likely that herders are concerned about ensuring their livestock have sustained access to optimal forage sources by avoiding other flocks using the same areas. Grazing activity is indirectly proportional to grazing speed. Grazing activity is lower in the herded zones (the morning–excitement/appetite moderation zone and the early afternoon–target zone, mean speed = 0.955 ± 0.006 km h−1) than when in an unherded zone (late afternoon–late afternoon meal, mean speed = 0.852 ± 0.010 km h−1). Mean distance travelled daily by herds in the herded zones was greatest (4.773 ± 0.029 km). In the wet season (7.365 ± 0.055 km) and a greater area was covered daily (10.6 ± 1.2 ha) as resources become more abundant relative to the dry season. This suggests that indigenous herding practices in Namaqualand require ecologically aware decision-making processes associated with effective resource use. Contemporary grazing management policies should be more inclusive of indigenous management as aspects of holistic grazing management have been embedded in these practices for centuries
Global plastic governance approaches and policy pathways for strengthening South Africa's circular plastics economy
(Elsevier B.V., 2026) Nicolaides, Stephanie Giselle; Fenton, Devlin Heywood; Nicolaides, Alexander George; Thomson, Scott; Rajkaran, Anusha
Plastic pollution has intensified into a major global environmental crisis, with single-use plastics (SUPs) and microplastics accumulating across terrestrial, freshwater, and marine systems. Although many countries have adopted bans, levies, and Extended Producer Responsibility (EPR) schemes, their effectiveness varies widely due to differences in governance capacity, enforcement, and socio-economic context. South Africa faces escalating plastic waste generation, weak municipal implementation, and limited regulation of microplastics, despite possessing a comprehensive legislative framework under the National Environmental Management: Waste Act and the National Waste Management Strategy. Addressing this gap between policy ambition and practical outcomes requires a clearer understanding of the policy instruments that have succeeded elsewhere. This article undertakes a comparative analysis of two contrasting but globally successful models, Rwanda and Germany, situated within a broader global benchmarking of plastic policy instruments to extract policy lessons relevant to South Africa. Rwanda demonstrates how strict bans, civic mobilisation through Umuganda, and strong enforcement can drive behavioural change in low-income contexts. Germany, by contrast, exemplifies an advanced circular economy model built on deposit-return schemes (DRS), eco-modulated EPR fees, and extensive recycling infrastructure. Drawing on secondary literature, legal instruments, and international benchmarks, the article identifies key principles applicable to South Africa: aligning regulatory bans with public education, ring-fencing EPR and levy revenues, strengthening municipal capacity, and formally integrating informal waste pickers into the value chain. The analysis concludes that while no single model is universally transferable, Rwanda and Germany offer foundational insights for designing just and circular plastic governance frameworks tailored to South Africa's socio-economic and institutional realities.
Grazing lawns affect vegetation composition and diversity of the endangered silcrete fynbos in the Bontebok National Park
(Elsevier B.V., 2026) Grootboom, Claire; Samuels, Mogamat Igshaan; Engelbrecht, Adriaan; Masubelele, Mmoto
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 overview of current knowledge on microalgae and macrophytes in south african estuaries, highlighting progress made and future research directions
(Elsevier B.V., 2026) Adams, Janine B.; Rajkaran, Anusha; Riddin, Taryn
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 organized 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 focused 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.
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 Ian; 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.
Impact of strong correlations observed in sugarcane responses to sodium chloride and mannitol within temporary immersion bioreactors
(Springer, 2025) Lozada, Alberto; Gómez, Daviel; Acosta, Yanier; Quintana-Zaez, Julio César; Companioni, Barbarita; Zevallos–Bravo, Byron E; de Lourdes Tapia y Figueroa, María; Naidoo, Sershen; Lorenzo, José Carlos
Sugarcane is a vital crop in tropical and subtropical regions worldwide, contributing to economic growth, energy production, and nutritional value. Over the past decade, numerous studies have demonstrated that in vitro screening for stress tolerance enables rapid evaluation of many plants, propagules, and explants for desirable traits, significantly accelerating the breeding process compared to traditional field methods. This report showcases the correlation between responses to NaCl (salinity) and mannitol (drought) in sugarcane plantlets micropropagated in temporary immersion bioreactors. With coefficients of determination (R2) exceeding 90%, the strongest correlations between sugarcane responses to salinity and drought were observed in the following indicators: shoot multiplication rate (90%), fresh weight of shoot clusters (97%), and levels of malondialdehydes (95%), other aldehydes (98%), carotenoids (95%), and soluble phenolics in the plantlets (96%). Soluble phenolics excreted into the culture medium showed an R2 of 86%, and chlorophyll a had an R2 of 78%. In contrast, chlorophyll b levels and cell wall-linked phenolics exhibited very low coefficients of determination (less than 25%). These findings highlight the strong physiological and biochemical responses of sugarcane to salinity and drought, particularly through phenolic metabolism and oxidative stress markers. The high coefficients of determination indicate reliable predictive relationships, suggesting that these indicators can serve as valuable biomarkers for stress tolerance. In contrast, the weak correlations observed in chlorophyll b and cell wall-linked phenolics underscore their limited relevance in assessing sugarcane resilience under these conditions.
Male polymorphism in bladder grasshoppers: a genetic analysis
(Taylor and Francis Ltd., 2025) Laubscher, Maxine; Engelbrecht, Adriaan; Couldridge, Vanessa C.K
Polymorphism in one sex often occurs amongst arthropods and is often linked with alternate mating strategies. Bladder grasshoppers show distinct polymorphism resulting in two different male morphs utilizing two different mating strategies. Primary males are larger in size and make use of acoustic communication to attract mates, while secondary (alternate) males are significantly smaller in size, flightless, and do not call, making use of a “sneaker” or satellite strategy. Three species of bladder grasshoppers have been described (Parabullacris vansoni, Paraphysemacris spinosus and Pneumoracris browni) that only have an alternate male morph and no primary male, whereas all other species in the family are described as having only a primary male. However, it is now known that both types of males occur in at least three species (Bullacris discolor, B. membracioides and B. obliqua). Thus, the validity of the taxonomic descriptions for species with no identified primary male has come into question. We therefore conducted a phylogenetic analysis to examine the genetic relationships between primary and secondary males for all species where secondary males are documented or suspected to occur. This was done using both mitochondrial (COI) and nuclear (ITS) DNA markers. We confirm that dimorphic males are indeed conspecific for the species observed to have both primary and alternate males. We also demonstrate that P. vansoni, P. browni and P. spinosus are invalid taxa as they are conspecific alternate male morphs of B. unicolor, Peringueyacris namaqua and Physemacris variolosa, respectively.
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.

Browse

Recent Submissions