Nelson Mandela University (formerly known as Nelson Mandela Metropolitan University (NMMU) ) and before that - the University of Port Elizabeth (UPE), the Port Elizabeth Technikon and Vista University's Port Elizabeth campus. This South African university has its main administration in the coastal city of Port Elizabeth. Nelson Mandela University was founded through a merger of three institutions in January 2005, but its history dates back to 1882, with the foundation of the Port Elizabeth Art School.Nelson Mandela University is a comprehensive university offering professional and vocational training. The university has seven campuses – six in Port Elizabeth and one in George. The main campus of the university is the South Campus. Students at Nelson Mandela University can study towards a diploma or a degree up to doctoral level qualifications. A number of courses include workplace experience as part of the curriculum at Nelson Mandela University. English is the university's medium of instruction.
Tropical savannas play a significant role in the global carbon cycle, yet they are increasingly being targeted for carbon sequestration through afforestation, assuming that tree planting will substantially boost carbon stocks in both biomass and soils. However, the response of soil organic carbon (SOC) to afforestation in these ecosystems remains highly uncertain, and the mechanisms driving this variability are not well understood. The dynamic boundaries between savannas and forests provide an ideal setting to study afforestation impacts on soil carbon storage and stability. Here, we sampled surface soils (0-15 cm) across six savanna-forest boundaries in Hluhluwe-iMfolozi Park, South Africa, and analysed patterns of SOC stocks, their particulate and mineral-associated organic carbon (POC and MAOC) and pyrogenic carbon (PyC) pools. Savanna and forest soils had comparable stocks of SOC, POC, MAOC and PyC, as well as similar proportions of POC and MAOC relative to SOC, except for the PyC proportion, which was significantly higher in savannas than in forests (p = 0.012). However, savanna-to-forest transitions induced a substantial turnover in carbon sources, with C3-derived carbon (mostly from trees) increasing from 55% to 99% in the POC pool and from 32% to 69% in the MAOC pool, thereby nearly eliminating legacy C4-grass-derived carbon in the POC. Additionally, although savanna-to-forest transitions had limited influence on all measured carbon pool sizes, these nonetheless varied substantially across transects. Specifically, stocks of SOC and MAOC (the dominant pool) were largely driven by differences in soil clay and silt content across the landscape. Synthesis. Contrary to the expectation that savanna-to-forest transitions would increase POC pools and subsequent SOC stocks, we found that MAOC remained the dominant contributor to SOC at this site, driven primarily by local variation in soil clay and silt content. While further studies are needed to test the generality of this pattern across tropical savannas, these findings highlight that soil texture may override the influence of vegetation change on soil carbon formation and persistence, and increasing tree cover may not guarantee soil carbon gains during savanna-to-forest transitions.
Remote sensing has provided a means to cover large areas of forest compartments through monitoring health and improving, sustainability of forest stands. The continued threat of existing pathogens, as well as the introduction of new pests or diseases, will require monitoring to aid in these practices. Thus, there exists a need to acquire information from the physiological process of plants that can potentially be related to stress, to aid in management and planning. Foliar temperature is directly linked to plant functions such as transpiration and stomatal conductance. Furthermore, a constant increase in temperature may indicate a lack of plant cooling and thus indicate water or pathogen stress. Thus, there is potential for temperature to be used as a representative of forest health, by indicating the presence of stress. This study succeeded in classifying disease manifestation affecting tree performance at a compartment level, by investigating the applicability of the thermal capabilities of a handheld FLIR camera, Landsat 9 and drone images to detect foliar damage from a pathogen. All three sensors scored high in algorithm scoring. The highest correlation of 72.2
Savannas, co-dominated by trees and grasses, are experiencing increasing tree cover driven by fire suppression and, in some regions, afforestation for carbon sequestration. Understanding how such vegetation shifts affect soil fungal communities, key regulators of carbon and nutrient cycling, is critical for managing savanna ecosystem functions. Yet, the effects of increasing tree cover on fungal diversity, composition, and functional groups, particularly in tropical savannas, remain poorly understood. We leveraged savanna-forest boundaries in Hluhluwe-iMfolozi Park, South Africa, as a natural space-for-time framework to examine fungal community changes during the savanna-to-forest transition. Soil samples were collected along six transects, and DNA was extracted for sequencing the ITS1 region. Our results show that alpha diversity of soil fungi did not differ significantly between savanna and forest soils, with comparable amplicon sequence variant richness, Shannon diversity, and Simpson evenness. However, savannas and forests were composed of substantially different fungal taxa and harbored distinct indicator genera, driven largely by high turnover, indicating that forest soils supported a largely new set of fungal taxa rather than a subset of savanna taxa. Despite this turnover, the relative abundance of major fungal guilds (mycorrhizal, pathogenic, saprotrophic) remained similar; only litter saprotrophs were significantly more abundant in forest soils than in savannas. These findings suggest that while fungal communities reorganize during vegetation change, broad functional redundancy maintains ecosystem processes across the savanna-to-forest transition.
Invasive alien plants are a major global threat to biodiversity and ecosystem function, particularly in regions of high endemism. Effective control of these species often relies on herbicides, yet their impacts on non-target vegetation in biodiversity-rich ecosystems remain poorly understood. This study assessed the effectiveness of various herbicides in controlling invasive alien species and the potential impact of the herbicides on surrounding non-target fynbos (Mediterranean shrubland) vegetation. Three sites invaded by Pinus, Acacia, and Eucalyptus were selected, where seven treatments were implemented per site, namely two controls (Untreated and Manual clearing) and five herbicide treatments (Imazapyr, Glyphosate, Picloram, Triclopyr, and Metsulfuron-methyl). Vegetation assessments were conducted in ten quadrats per treatment plot over 259 days. Clearing invasive trees resulted in increased abundance of non-target vegetation functional groups, including grasses, broadleaves, and indigenous shrubs and trees. When cut-stumps were treated with herbicide, only eucalypts coppiced. Vegetation cover initially declined post-clearing but later recovered in treated plots, whereas the Untreated control saw continued suppression by invasives. Herbicide bioassays further indicated an absence of biologically active residues in the topsoil. The accumulative change in vegetation cover over time highlighted significant trends in treatments despite site variability. Metsulfuron-methyl, Triclopyr, Picloram, and Glyphosate were the most effective treatments for invasive suppression, vegetation recovery, and environmental sustainability. While Imazapyr showed high efficacy, its environmental impact made it less favorable. These findings enable responsible herbicide use in conservation-driven invasive species management.
Diatom-based indices are widely used for freshwater bioassessment, yet methodological variability, particularly in count strategies, can influence ecological classification outcomes. This study compares a traditional fixed count (FC) approach with an observed/expected taxa (OE) strategy across five riverine sites in the Eastern Cape, South Africa. A total of 230 diatom taxa were identified. Comparisons between the two approaches revealed statistically significant differences in some ecological status classifications, although both methods captured similar spatial trends across the study area. The OE approach required counting fewer valves per sample, reducing analysis time without compromising assessment accuracy. While the OE taxa approach may provide a time-efficient alternative to FC methods, the differences detected between methods underscore the need for a critical evaluation of their limitations and further testing before routine application.
