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Jasper Knight

University of the Witwatersrand, Geography, Archaeology and Environmental Studies, Faculty Member

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I am a geoscientist with research interests in the spatial and temporal variability in morphosedimentary system responses to rapid hemispheric-scale climatic and environmental changes during the late Pleistocene and Holocene. I focus thematically on glaciers, rivers, coasts and mountains. I focus geographically on Africa, Ireland, northwest USA, Australia, the European Alps, and various places in Asia and South America. You should be able to download the pdfs of papers, but if you want more information please email me, jasper.knight-at-wits.ac.za
Address: School of Geography, Archaeology and Environmental Studies,
University of the Witwatersrand,
Private Bag 3,
Wits 2050, Johannesburg, South Africa

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Books by Jasper Knight

Landscapes and Landforms of the Central Sahara

The Geography of South Africa: Contemporary Changes and New Directions

This edited collection seeks to examine contemporary directions in geographical research on South... more This edited collection seeks to examine contemporary directions in geographical research on South Africa. It encompasses a cross section of selected themes of critical importance not only to the discipline of Geography in South Africa, but also of relevance to other areas of the Global South. All chapters are original contributions, providing a state of the art research baseline on key themes in physical, human and environmental geography, and in understanding the changing geographical landscapes of modern South Africa. These contributions set the scene for an understanding of the relationships between modern South Africa and the wider contemporary world, including issues of sustainable development and growth in the Global South.

Quaternary Environmental Change in Southern Africa: Human and Physical Dimensions

Landscapes and Landforms of South Africa

Introduction to Coastal Processes and Geomorphology

Periglacial and Paraglacial Processes and Environments

North of Ireland: Field Guide

High Resolution Morphodynamics and Sedimentary Evolution of Estuaries

Field Guide to the Coastal Environments of Northern Ireland

Lower Bann and adjacent areas

Papers by Jasper Knight

Coastal boulder movement on a rocky shoreline in northwest Ireland from repeat UAV surveys using Structure from Motion photogrammetry

The degree of boulder mobility in response to coastal storms likely varies spatially and temporal... more The degree of boulder mobility in response to coastal storms likely varies spatially and temporally along rocky shorelines, but this is difficult to evaluate from field monitoring of individual boulders alone. Structure from Motion (SfM) photogrammetry can be used to analyse changes in shoreline geomorphology or boulder distributions over time and space from rocky shorelines. This study employs data from repeated Unpiloted Aerial Vehicle (UAV) surveys in 2017, 2018, 2019 and 2022 along a 1-km stretch of a rocky shoreline in northwest Ireland. SfM techniques were used to generate orthomosaics of the bedrock platform surface from which distributions and transport patterns of boulders were examined. Based on the identification of specific boulders that appear in images from successive time slices, 16-32 % of boulders had remained stationary (had either rotated or flipped on the spot, but experienced no change in boulder position), 18-39 % had moved but less than the calculated Root Mean Square Error (RMSE) value of 23 cm, and 29-66 % of boulders had moved greater than the RMSE value, and <29 m distance in one case. In addition, a significant minority of boulders also appeared or disappeared (3-23 %) between successive time slices, which may reflect their episodic transport to/from the sea or beyond the region of interest. Overall, the results indicate that boulder movement is highly variable over time and space and does not appear to correspond with episodic wave forcing. This is different to previous studies that have described a simple deterministic relationship between boulder movement and singular wave forcing events such as storms. Repeated UAV surveys provide a consistent methodology for understanding rocky shoreline and boulder dynamics, and can offer insight into shoreline sensitivity to regional wave climate operating under more normal or 'average' conditions.

Projected changes in rainfall amount and distribution in the Democratic Republic of Congo – evidence from an ensemble of high-resolution climate simulations

Extreme precipitation has been threatening many sectors of human society and is likely to intensi... more Extreme precipitation has been threatening many sectors of human society and is likely to intensify with global warming. In the present study, we have analysed the impact of future climate change on daily mean rainfall and heavy rainfall on seasonal and annual scales in the Democratic Republic of Congo (DRC) by using ten long-term runs of high-resolution regional climate models. We initially assessed the performance of each run and the multimodel ensemble mean in simulating the daily mean rainfall (PRE), the maximum one-day rainfall (Rx1day), the simple rainfall intensity index (SDII), the count of days when rainfall is greater than or equal to 20 mm (RR20mm), the total rainfall when the daily rainfall exceeds the 95th percentile of the wet-day rainfall (R95p) and the maximum number of consecutive days with more than or equal to 1 mm (CWD). Next, we examined the future changes of these indices, focusing on the multi-model ensemble mean and spread under the high emission scenario RCP8.5. The time frames considered are the mid and end of the twenty-first century (2035-2065 and 2070-2100, respectively). The results indicate that the performance of REMO2015-MPI-ESM was close to the multi-model ensemble mean in representing the mean rainfall and most heavy rainfall indices, while CanRCM4-CamESM2 was identified as the worst performing model. The key finding of this study is that the multi-model ensemble mean project no significant change regarding the daily mean rainfall throughout the year and across all seasons by the middle of the 21st century, except of the western region of the country where a decrease is projected. Simultaneously, Rx1day, SDII, RR20mm, and R95p are projected to decrease almost everywhere during all seasons. Moreover, a consistent decrease in the number of wet days is projected. Focusing on the end of the century, the multi-model ensemble mean project an overall decrease in daily mean rainfall, especially in the western region of the DRC, with a more pronounced effect during MAM. The increase in Rx1day, SDII, RR20mm, and R95p, along with a decrease in CWD, is amplified in this period. These findings are useful for predicting the potential threats of precipitation-related diseases and natural hazards, as well as for designing climate-resilient infrastructure and socioeconomic activities in the DRC.

Adaptation to Climate Change and Variability by Farming Households in North-Central Nigeria

Climate change and variability present major environmental and socioeconomic challenges to popula... more Climate change and variability present major environmental and socioeconomic challenges to populations in sub-Saharan Africa that depend upon favourable climatic conditions for agricul-tural production and for their sustenance and livelihoods. This study assesses the adaptation strategies employed by farming households in north-central Nigeria to reduce the impacts of persistent ongoing climate variability, mainly changes in rainfall and temperatures, as a result of climate change. Data were collected through household questionnaires from 120 farming households in Bokkos Local Government Area, Plateau State, north-central Nigeria. Results in-dicate that farmers are aware of and can recognize changing weather and climate patterns and that they adopt a range of on-farm and off-farm adaptation strategies. On-farm activities include changing crop planting time, crop diversification, and irrigation farming; the use of fertilizers, manure and agro-chemicals to boost crop yield; and planting of disease-resistant and drought-tolerant crop varieties. Off-farm activities include small-scale trading and artisanal ventures that can augment the household income. Together, these diverse activities can enhance household resilience against the negative effects of climate variability. It is recommended that policymakers improve institutional support and training to farmers to enable viable livelihood diversification strategies, enhancing their climate change adaptation and resilience.

The geomorphology and neotectonics of the Vaalputs Radioactive Waste Disposal Facility site, Namaqualand, South Africa: Palaeoseismological and geodynamic implications

The safe disposal of radioactive waste products remains a challenging and controversial issue, ye... more The safe disposal of radioactive waste products remains a challenging and controversial issue, yet their burial in a stable geological environment is the option favoured by most countries. Past investigations of the Vaalputs facility in South Africa’s semi-arid Bushmanland Plateau demonstrated its suitability for the disposal of low-level, short-lived (<300 years) radioactive waste, but also the need for more data on hazardous seismotectonic and climatic processes for the potential storage of longer-lived spent nuclear fuel. We review and then provide new information on the regional geomorphological and morphotectonic features of the Bushmanland Plateau, focusing on pedogenic features and compressive shear fractures in the trenches excavated over the past two decades. The fractures, provisionally dated between ~75 ka and ~46 ka, resemble east-verging thrust faults of limited horizontal displacement (≤1 m) and die out at depths of 4 m. Having discounted a pedogenic origin, the shear fractures likely represent stress relief structures triggered by the seismogenic reactivation of one of the Quaternary active faults in the area. The most likely candidate is the Santab Fault Zone (SFZ), which has a strike length ≥20 km and a throw of up to ~5 m at its closest point (8 km) to the Vaalputs site. Regional remote sensing and off-site investigations in the Bushmanland Plateau relate the neotectonic episodes at Vaalputs and environs to a late Pleistocene climax of the Namaqualand seismic source zone. This zone is characterised by the Wegener Stress Anomaly, a long-lived ~NW-SE oriented compression that, at its apex in the Late Santonian, caused large scale folding and thrusting not only in Bushmanland and parts of central-southern Namibia, but also swept across the entire African plate.

Factors controlling soil organic matter stock: A baseline study for evaluating carbon storage initiatives in Miombo woodlands, Zambia

Soil organic matter (SOM) is a key component of forest productivity and soil organic carbon stock... more Soil organic matter (SOM) is a key component of forest productivity and soil organic carbon stock. However, little is known about SOM and carbon variability in miombo woodlands, which is a significant ecosystem in sub-Sahara African forests and vital for strategies towards REDD+ (Reducing Emissions from Deforestation and Forest Degradation). In this study, nine edaphic factors were measured and used to analyse the variability of SOM in miombo woodland sites with different tree structures in Luanshya, Zambia. The findings showed a large variability of SOM stocks at different soil depths: 36.67 to 113.89 Mg ha-1 at 0–10 cm depth, 28.67 to 79.56 Mg ha-1 at 10–20 cm depth, and 31.89 to 98.56 Mg ha-1 at 20–30 cm depth. These SOM values at different depths also varied between miombo woodland sites of different successional stages or management practices, notably that areas affected by recent tree clearance had higher than average SOM content per layer (0–10 cm: +5.57%; 10–20 cm: +4.20%; 20–30 cm: +4.30%). Canonical correspondence analysis (CCA) revealed that the most significant environmental and management factors influencing SOM were woodland thinning by clearance, and silt content within soils. This study highlights that CCA can be used to show the relative importance of different forest properties and edaphic factors in determining miombo SOM content. The results of this study are particularly relevant for addressing current REDD+ reforestation and management strategies that are aimed at increasing carbon stocks in the tropical forests of sub-Saharan Africa.

Compliance with the Nagoya protocol in the Southern African Development Community

The Nagoya Protocol (2010) provides an international framework for access and benefits sharing of... more The Nagoya Protocol (2010) provides an international framework for access and benefits sharing of genetic resources. In the Southern African Development Community (SADC), the means to deliver compliance with the principles of the Nagoya Protocol is through national-scale legislative and management frameworks. However, there may be differences between the policies and practices of individual countries within the SADC region that may limit the effectiveness of how the principles of the Nagoya Protocol are enacted. This study describes the legislative and management frameworks for enacting the principles of the Nagoya Protocol that are found in each of the sixteen SADC countries. Particular emphasis is placed on strategies for genetic and associated biological resource diversity and management, the role of stakeholders, local communities and traditional (indigenous) knowledge systems in each country. Results show that the legislative and management frameworks for managing the Nagoya Protocol are highly variable across the SADC region. There are also variable levels of engagement with the Access and Benefit-Sharing Clearing House (which relates to the implementation of the principles of the Nagoya Protocol), and with reporting to the International Treaty on Plant Genetic Resources for Food and Agriculture which is a requirement of compliance. This study makes recommendations for the sharing of best practices for access and benefit sharing, and for developing protocols for engagement with local communities and other stakeholders on genetic and biological resource exploitation across the SADC region.

Evaluating the Impacts of a Research Ethics Training Course on University Researchers

Training in research ethics is an essential part of professional development for graduate student... more Training in research ethics is an essential part of professional development for graduate students and academic and research staff at universities and other research institutions. Certificated training in research ethics has been offered at the University of the Witwatersrand, Johannesburg, South Africa, since 2019. This training comprises a 4 h content-based workshop followed by a written assignment with attendees who are mainly graduate students and academic staff of the University. This study presents the results of an anonymous online survey that evaluated the impacts of the ethics training on researcher professional activities, in particular where their research deals with human participants. Those invited to take part in the survey were the successful attendees who had attained a Certificate of Competence in Research Ethics. Results (n = 92) showed that the majority of respondents were satisfied with the nature, format and depth of content of the training, and reported that it has a positive impact on their development as researchers. Specifically, this included thinking through their project design, and developing critical thinking and problem solving skills related to their project. Overall, the results highlight the importance of research ethics training in researcher development, as well as engendering critical reflection on ethical issues in different research contexts. It also shows the importance of ethics training in a ‘live’ session where participants are able to ask questions, engage in debate, and undertake a written assessment that tests their application of ethics concepts.

Nature-based solutions for coastal resilience in South Africa

Coastlines globally are highly sensitive to the effects of anthropogenic climate change through t... more Coastlines globally are highly sensitive to the effects of anthropogenic climate change through the mechanisms of sea-level rise, increased coastal storminess, and changes in coastal sediment supply and sediment dynamics. Coastlines are also influenced by land use change, urbanization and development of built infrastructure on the coastal hinterland. Both of these sources of forcings affect the maintenance and dynamics of coastal landforms; they can weaken coastal resilience, and make coasts more sensitive to climate hazards. This study critically examines the properties of rocky and sandy coastlines that contribute to coastal biophysical resilience in South Africa, highlighting their relative rates of change and dynamic behaviour over recent decades in response to forcing by physical and human factors in combination. Coastal landforms can be considered as ‘green infrastructure’ that can buffer the effects of climate forcing, as well as provide a range of ecosystem and environmental services in their own right. Viewing coastal landforms as green infrastructure provides a ‘nature-based solution’ to mitigate against climate change impacts that can work with – not against – the natural geomorphic, sedimentary and ecological processes of coastlines. Coastal landforms can also contribute to socioecological resilience, where they provide environmental and ecosystem services to communities. This multifaceted interpretation of coastal resilience can result in reduced climate impacts whilst at the same time retaining coastal ecological and geomorphic function. The green infrastructure approach has not been well developed in South Africa but is more effective in supporting coastal sustainable development.

Evaluation of river mouth dynamics along the Eastern Cape coastline, South Africa

Small rivers that flow into the sea often terminate in estuaries or lagoons that may be separated... more Small rivers that flow into the sea often terminate in estuaries or lagoons that may be separated from the sea by a sandy beach barrier. As a result of variations in barrier width and river discharge, these river mouths can be variously open, closed or partly open at different times. This behaviour reflects the interplay between the processes and properties of river systems (discharge, sediment supply, channel width, water velocity) and beach systems (beach width and height, grain size, wave regime, longshore processes). This study examines the dynamic behaviour of 32 river mouths located along 238 km of the coastline of Eastern Cape Province, South Africa, between 2000 and 2021 using Google Earth imagery. At each available time snapshot, individual river mouths were classified along a continuum as open, partly open or closed. Results show that nine river mouths were permanently open whereas 22 varied between the three states. Only one river mouth was partly open and none was closed for the entire period. Some spatial and temporal patterns were also identified. Commonly, adjacent river mouths may show the same patterns of opening/closing, which may reflect regional climate forcing. Fewer river mouths are open during winter/autumn compared to summer, likely reflecting rainfall seasonality. Thus, regional climate is considered to be the major control on river mouth dynamics, likely in combination with human activities that impact on river discharge, although the role of coastal sediment dynamics is significantly less well understood. The interplay between these different forcing factors requires further investigation.

The sensitivity and evolutionary trajectory of the mountain cryosphere and implications for mountain geomorphic systems and hazards

Global climate change gives rise to changing spatial patterns of snow and ice, especially over mo... more Global climate change gives rise to changing spatial patterns of snow and ice, especially over mountain blocks where orographic and synoptic circulation effects play significant roles in creating patterns of precipitation and glacier development. The presence of snow and ice results in heat balance changes and other land surface feedbacks that have implications for patterns of mountain glacier retreat and the dynamics of mountain geomorphic systems. This study considers the sensitivity of the mountain cryosphere (snow, ice, permafrost) to global climate change, and the implications of this sensitivity analysis for evaluating mountain surface stability, geomorphic change and the generation of mountain geohazards. Consideration of these issues is informed by evidence from case studies reported in the literature and by field observations of mountain system dynamics worldwide. Results show that ‘sensitivity’ to climate forcing has been interpreted and defined in different ways in mountain snow, ice and permafrost systems, with respect to properties such as albedo, mass balance or rapidity of system change. There are also significant spatial differences in sensitivity between different mountain blocks for snow, ice and permafrost, and these regions are therefore likely to follow different trajectories of geomorphic change in response to climate forcing, related to their physiographic properties and the extent of cryospheric coverage. Within glaciated mountains in particular, the relative timing of different geomorphic events, and the interplay between slope, glacier front and proglacial sediment sources and environments, may vary depending on glacier size, geomorphic setting and microclimate. By contrast, responses to permafrost warming (increased surface instability and mass movements) and changes in snow patterns (avalanche risk, floods) may have quite different spatial and temporal patterns and influenced by different environmental controls. An integrated evolutionary model for mountain system development under a changing cryosphere is proposed, highlighting the critical role of energy balance as a forcing factor that then triggers downstream mountain system responses. This suggests that different elements of mountain systems exhibit different sensitivities, and furthermore that these sensitivities change over time and space through the period of anthropogenic global warming and paraglacial relaxation.

Landscapes and Landforms of the Central Sahara

The Geography of South Africa: Contemporary Changes and New Directions

This edited collection seeks to examine contemporary directions in geographical research on South... more This edited collection seeks to examine contemporary directions in geographical research on South Africa. It encompasses a cross section of selected themes of critical importance not only to the discipline of Geography in South Africa, but also of relevance to other areas of the Global South. All chapters are original contributions, providing a state of the art research baseline on key themes in physical, human and environmental geography, and in understanding the changing geographical landscapes of modern South Africa. These contributions set the scene for an understanding of the relationships between modern South Africa and the wider contemporary world, including issues of sustainable development and growth in the Global South.

Quaternary Environmental Change in Southern Africa: Human and Physical Dimensions

Landscapes and Landforms of South Africa

Introduction to Coastal Processes and Geomorphology

Periglacial and Paraglacial Processes and Environments

North of Ireland: Field Guide

High Resolution Morphodynamics and Sedimentary Evolution of Estuaries

Field Guide to the Coastal Environments of Northern Ireland

Lower Bann and adjacent areas

Coastal boulder movement on a rocky shoreline in northwest Ireland from repeat UAV surveys using Structure from Motion photogrammetry

The degree of boulder mobility in response to coastal storms likely varies spatially and temporal... more The degree of boulder mobility in response to coastal storms likely varies spatially and temporally along rocky shorelines, but this is difficult to evaluate from field monitoring of individual boulders alone. Structure from Motion (SfM) photogrammetry can be used to analyse changes in shoreline geomorphology or boulder distributions over time and space from rocky shorelines. This study employs data from repeated Unpiloted Aerial Vehicle (UAV) surveys in 2017, 2018, 2019 and 2022 along a 1-km stretch of a rocky shoreline in northwest Ireland. SfM techniques were used to generate orthomosaics of the bedrock platform surface from which distributions and transport patterns of boulders were examined. Based on the identification of specific boulders that appear in images from successive time slices, 16-32 % of boulders had remained stationary (had either rotated or flipped on the spot, but experienced no change in boulder position), 18-39 % had moved but less than the calculated Root Mean Square Error (RMSE) value of 23 cm, and 29-66 % of boulders had moved greater than the RMSE value, and <29 m distance in one case. In addition, a significant minority of boulders also appeared or disappeared (3-23 %) between successive time slices, which may reflect their episodic transport to/from the sea or beyond the region of interest. Overall, the results indicate that boulder movement is highly variable over time and space and does not appear to correspond with episodic wave forcing. This is different to previous studies that have described a simple deterministic relationship between boulder movement and singular wave forcing events such as storms. Repeated UAV surveys provide a consistent methodology for understanding rocky shoreline and boulder dynamics, and can offer insight into shoreline sensitivity to regional wave climate operating under more normal or 'average' conditions.

Projected changes in rainfall amount and distribution in the Democratic Republic of Congo – evidence from an ensemble of high-resolution climate simulations

Extreme precipitation has been threatening many sectors of human society and is likely to intensi... more Extreme precipitation has been threatening many sectors of human society and is likely to intensify with global warming. In the present study, we have analysed the impact of future climate change on daily mean rainfall and heavy rainfall on seasonal and annual scales in the Democratic Republic of Congo (DRC) by using ten long-term runs of high-resolution regional climate models. We initially assessed the performance of each run and the multimodel ensemble mean in simulating the daily mean rainfall (PRE), the maximum one-day rainfall (Rx1day), the simple rainfall intensity index (SDII), the count of days when rainfall is greater than or equal to 20 mm (RR20mm), the total rainfall when the daily rainfall exceeds the 95th percentile of the wet-day rainfall (R95p) and the maximum number of consecutive days with more than or equal to 1 mm (CWD). Next, we examined the future changes of these indices, focusing on the multi-model ensemble mean and spread under the high emission scenario RCP8.5. The time frames considered are the mid and end of the twenty-first century (2035-2065 and 2070-2100, respectively). The results indicate that the performance of REMO2015-MPI-ESM was close to the multi-model ensemble mean in representing the mean rainfall and most heavy rainfall indices, while CanRCM4-CamESM2 was identified as the worst performing model. The key finding of this study is that the multi-model ensemble mean project no significant change regarding the daily mean rainfall throughout the year and across all seasons by the middle of the 21st century, except of the western region of the country where a decrease is projected. Simultaneously, Rx1day, SDII, RR20mm, and R95p are projected to decrease almost everywhere during all seasons. Moreover, a consistent decrease in the number of wet days is projected. Focusing on the end of the century, the multi-model ensemble mean project an overall decrease in daily mean rainfall, especially in the western region of the DRC, with a more pronounced effect during MAM. The increase in Rx1day, SDII, RR20mm, and R95p, along with a decrease in CWD, is amplified in this period. These findings are useful for predicting the potential threats of precipitation-related diseases and natural hazards, as well as for designing climate-resilient infrastructure and socioeconomic activities in the DRC.

Adaptation to Climate Change and Variability by Farming Households in North-Central Nigeria

Climate change and variability present major environmental and socioeconomic challenges to popula... more Climate change and variability present major environmental and socioeconomic challenges to populations in sub-Saharan Africa that depend upon favourable climatic conditions for agricul-tural production and for their sustenance and livelihoods. This study assesses the adaptation strategies employed by farming households in north-central Nigeria to reduce the impacts of persistent ongoing climate variability, mainly changes in rainfall and temperatures, as a result of climate change. Data were collected through household questionnaires from 120 farming households in Bokkos Local Government Area, Plateau State, north-central Nigeria. Results in-dicate that farmers are aware of and can recognize changing weather and climate patterns and that they adopt a range of on-farm and off-farm adaptation strategies. On-farm activities include changing crop planting time, crop diversification, and irrigation farming; the use of fertilizers, manure and agro-chemicals to boost crop yield; and planting of disease-resistant and drought-tolerant crop varieties. Off-farm activities include small-scale trading and artisanal ventures that can augment the household income. Together, these diverse activities can enhance household resilience against the negative effects of climate variability. It is recommended that policymakers improve institutional support and training to farmers to enable viable livelihood diversification strategies, enhancing their climate change adaptation and resilience.

The geomorphology and neotectonics of the Vaalputs Radioactive Waste Disposal Facility site, Namaqualand, South Africa: Palaeoseismological and geodynamic implications

The safe disposal of radioactive waste products remains a challenging and controversial issue, ye... more The safe disposal of radioactive waste products remains a challenging and controversial issue, yet their burial in a stable geological environment is the option favoured by most countries. Past investigations of the Vaalputs facility in South Africa’s semi-arid Bushmanland Plateau demonstrated its suitability for the disposal of low-level, short-lived (<300 years) radioactive waste, but also the need for more data on hazardous seismotectonic and climatic processes for the potential storage of longer-lived spent nuclear fuel. We review and then provide new information on the regional geomorphological and morphotectonic features of the Bushmanland Plateau, focusing on pedogenic features and compressive shear fractures in the trenches excavated over the past two decades. The fractures, provisionally dated between ~75 ka and ~46 ka, resemble east-verging thrust faults of limited horizontal displacement (≤1 m) and die out at depths of 4 m. Having discounted a pedogenic origin, the shear fractures likely represent stress relief structures triggered by the seismogenic reactivation of one of the Quaternary active faults in the area. The most likely candidate is the Santab Fault Zone (SFZ), which has a strike length ≥20 km and a throw of up to ~5 m at its closest point (8 km) to the Vaalputs site. Regional remote sensing and off-site investigations in the Bushmanland Plateau relate the neotectonic episodes at Vaalputs and environs to a late Pleistocene climax of the Namaqualand seismic source zone. This zone is characterised by the Wegener Stress Anomaly, a long-lived ~NW-SE oriented compression that, at its apex in the Late Santonian, caused large scale folding and thrusting not only in Bushmanland and parts of central-southern Namibia, but also swept across the entire African plate.

Factors controlling soil organic matter stock: A baseline study for evaluating carbon storage initiatives in Miombo woodlands, Zambia

Soil organic matter (SOM) is a key component of forest productivity and soil organic carbon stock... more Soil organic matter (SOM) is a key component of forest productivity and soil organic carbon stock. However, little is known about SOM and carbon variability in miombo woodlands, which is a significant ecosystem in sub-Sahara African forests and vital for strategies towards REDD+ (Reducing Emissions from Deforestation and Forest Degradation). In this study, nine edaphic factors were measured and used to analyse the variability of SOM in miombo woodland sites with different tree structures in Luanshya, Zambia. The findings showed a large variability of SOM stocks at different soil depths: 36.67 to 113.89 Mg ha-1 at 0–10 cm depth, 28.67 to 79.56 Mg ha-1 at 10–20 cm depth, and 31.89 to 98.56 Mg ha-1 at 20–30 cm depth. These SOM values at different depths also varied between miombo woodland sites of different successional stages or management practices, notably that areas affected by recent tree clearance had higher than average SOM content per layer (0–10 cm: +5.57%; 10–20 cm: +4.20%; 20–30 cm: +4.30%). Canonical correspondence analysis (CCA) revealed that the most significant environmental and management factors influencing SOM were woodland thinning by clearance, and silt content within soils. This study highlights that CCA can be used to show the relative importance of different forest properties and edaphic factors in determining miombo SOM content. The results of this study are particularly relevant for addressing current REDD+ reforestation and management strategies that are aimed at increasing carbon stocks in the tropical forests of sub-Saharan Africa.

Compliance with the Nagoya protocol in the Southern African Development Community

The Nagoya Protocol (2010) provides an international framework for access and benefits sharing of... more The Nagoya Protocol (2010) provides an international framework for access and benefits sharing of genetic resources. In the Southern African Development Community (SADC), the means to deliver compliance with the principles of the Nagoya Protocol is through national-scale legislative and management frameworks. However, there may be differences between the policies and practices of individual countries within the SADC region that may limit the effectiveness of how the principles of the Nagoya Protocol are enacted. This study describes the legislative and management frameworks for enacting the principles of the Nagoya Protocol that are found in each of the sixteen SADC countries. Particular emphasis is placed on strategies for genetic and associated biological resource diversity and management, the role of stakeholders, local communities and traditional (indigenous) knowledge systems in each country. Results show that the legislative and management frameworks for managing the Nagoya Protocol are highly variable across the SADC region. There are also variable levels of engagement with the Access and Benefit-Sharing Clearing House (which relates to the implementation of the principles of the Nagoya Protocol), and with reporting to the International Treaty on Plant Genetic Resources for Food and Agriculture which is a requirement of compliance. This study makes recommendations for the sharing of best practices for access and benefit sharing, and for developing protocols for engagement with local communities and other stakeholders on genetic and biological resource exploitation across the SADC region.

Evaluating the Impacts of a Research Ethics Training Course on University Researchers

Training in research ethics is an essential part of professional development for graduate student... more Training in research ethics is an essential part of professional development for graduate students and academic and research staff at universities and other research institutions. Certificated training in research ethics has been offered at the University of the Witwatersrand, Johannesburg, South Africa, since 2019. This training comprises a 4 h content-based workshop followed by a written assignment with attendees who are mainly graduate students and academic staff of the University. This study presents the results of an anonymous online survey that evaluated the impacts of the ethics training on researcher professional activities, in particular where their research deals with human participants. Those invited to take part in the survey were the successful attendees who had attained a Certificate of Competence in Research Ethics. Results (n = 92) showed that the majority of respondents were satisfied with the nature, format and depth of content of the training, and reported that it has a positive impact on their development as researchers. Specifically, this included thinking through their project design, and developing critical thinking and problem solving skills related to their project. Overall, the results highlight the importance of research ethics training in researcher development, as well as engendering critical reflection on ethical issues in different research contexts. It also shows the importance of ethics training in a ‘live’ session where participants are able to ask questions, engage in debate, and undertake a written assessment that tests their application of ethics concepts.

Nature-based solutions for coastal resilience in South Africa

Coastlines globally are highly sensitive to the effects of anthropogenic climate change through t... more Coastlines globally are highly sensitive to the effects of anthropogenic climate change through the mechanisms of sea-level rise, increased coastal storminess, and changes in coastal sediment supply and sediment dynamics. Coastlines are also influenced by land use change, urbanization and development of built infrastructure on the coastal hinterland. Both of these sources of forcings affect the maintenance and dynamics of coastal landforms; they can weaken coastal resilience, and make coasts more sensitive to climate hazards. This study critically examines the properties of rocky and sandy coastlines that contribute to coastal biophysical resilience in South Africa, highlighting their relative rates of change and dynamic behaviour over recent decades in response to forcing by physical and human factors in combination. Coastal landforms can be considered as ‘green infrastructure’ that can buffer the effects of climate forcing, as well as provide a range of ecosystem and environmental services in their own right. Viewing coastal landforms as green infrastructure provides a ‘nature-based solution’ to mitigate against climate change impacts that can work with – not against – the natural geomorphic, sedimentary and ecological processes of coastlines. Coastal landforms can also contribute to socioecological resilience, where they provide environmental and ecosystem services to communities. This multifaceted interpretation of coastal resilience can result in reduced climate impacts whilst at the same time retaining coastal ecological and geomorphic function. The green infrastructure approach has not been well developed in South Africa but is more effective in supporting coastal sustainable development.

Evaluation of river mouth dynamics along the Eastern Cape coastline, South Africa

Small rivers that flow into the sea often terminate in estuaries or lagoons that may be separated... more Small rivers that flow into the sea often terminate in estuaries or lagoons that may be separated from the sea by a sandy beach barrier. As a result of variations in barrier width and river discharge, these river mouths can be variously open, closed or partly open at different times. This behaviour reflects the interplay between the processes and properties of river systems (discharge, sediment supply, channel width, water velocity) and beach systems (beach width and height, grain size, wave regime, longshore processes). This study examines the dynamic behaviour of 32 river mouths located along 238 km of the coastline of Eastern Cape Province, South Africa, between 2000 and 2021 using Google Earth imagery. At each available time snapshot, individual river mouths were classified along a continuum as open, partly open or closed. Results show that nine river mouths were permanently open whereas 22 varied between the three states. Only one river mouth was partly open and none was closed for the entire period. Some spatial and temporal patterns were also identified. Commonly, adjacent river mouths may show the same patterns of opening/closing, which may reflect regional climate forcing. Fewer river mouths are open during winter/autumn compared to summer, likely reflecting rainfall seasonality. Thus, regional climate is considered to be the major control on river mouth dynamics, likely in combination with human activities that impact on river discharge, although the role of coastal sediment dynamics is significantly less well understood. The interplay between these different forcing factors requires further investigation.

The sensitivity and evolutionary trajectory of the mountain cryosphere and implications for mountain geomorphic systems and hazards

Global climate change gives rise to changing spatial patterns of snow and ice, especially over mo... more Global climate change gives rise to changing spatial patterns of snow and ice, especially over mountain blocks where orographic and synoptic circulation effects play significant roles in creating patterns of precipitation and glacier development. The presence of snow and ice results in heat balance changes and other land surface feedbacks that have implications for patterns of mountain glacier retreat and the dynamics of mountain geomorphic systems. This study considers the sensitivity of the mountain cryosphere (snow, ice, permafrost) to global climate change, and the implications of this sensitivity analysis for evaluating mountain surface stability, geomorphic change and the generation of mountain geohazards. Consideration of these issues is informed by evidence from case studies reported in the literature and by field observations of mountain system dynamics worldwide. Results show that ‘sensitivity’ to climate forcing has been interpreted and defined in different ways in mountain snow, ice and permafrost systems, with respect to properties such as albedo, mass balance or rapidity of system change. There are also significant spatial differences in sensitivity between different mountain blocks for snow, ice and permafrost, and these regions are therefore likely to follow different trajectories of geomorphic change in response to climate forcing, related to their physiographic properties and the extent of cryospheric coverage. Within glaciated mountains in particular, the relative timing of different geomorphic events, and the interplay between slope, glacier front and proglacial sediment sources and environments, may vary depending on glacier size, geomorphic setting and microclimate. By contrast, responses to permafrost warming (increased surface instability and mass movements) and changes in snow patterns (avalanche risk, floods) may have quite different spatial and temporal patterns and influenced by different environmental controls. An integrated evolutionary model for mountain system development under a changing cryosphere is proposed, highlighting the critical role of energy balance as a forcing factor that then triggers downstream mountain system responses. This suggests that different elements of mountain systems exhibit different sensitivities, and furthermore that these sensitivities change over time and space through the period of anthropogenic global warming and paraglacial relaxation.

The last glaciers in Africa and their environmental implications

Climate models and ongoing monitoring studies predict the remaining glaciers in Africa are predic... more Climate models and ongoing monitoring studies predict the remaining glaciers in Africa are predicted to disappear by the middle of the 21st Century. These will likely be the only glaciers present on the continent for some tens of thousands of years, until the next global ice age. This paper considers the implications of the shrinking cryosphere in Africa for the surrounding environment and local communities. Glacier retreat will give rise to significant and irreversible downstream effects on East African mountain landscapes in future decades, including impacts on water resources; slope stability and geohazards; ecosystems and ecosystem services; and human socioeconomic and cultural activities and heritage. This foresight study is the first to discuss future environmental impacts of deglacierization in East Africa, and this is framed around understanding the interconnections that exist between physical and human landscape elements in mountainous regions. A key outcome is the identification of elements of mountain systems that are most sensitive to environmental disturbance as a result of global warming, such as long-term water availability and processes that give rise to geohazards, and highlighting the need for management and mitigation of these varied impacts.

Monitoring of Coastal Boulder Movements by Storms and Calculating Volumetric Parameters Using the Volume Differential Method Based on Point Cloud Difference

The measurement of boulder volume and axial length plays a significant role in exploring the evol... more The measurement of boulder volume and axial length plays a significant role in exploring the evolution of coastal boulder deposition, which provides a theoretical framework to examine the hydrodynamics of extreme wave events. At present, the application of Structure-from-Motion (SfM) to unmanned aerial system (UAS) imagery is one of the most used boulder surveying techniques. However, the monitoring of boulder movement and accurate measurement of boul-der morphometrics are rarely investigated in combination. In this study, UAS surveys are used to monitor moving boulders and measure boulder volumes using the volume differential meth-od based on the difference of dense point clouds. This is undertaken at a site on the rocky shore-line of northwest Ireland in three repeated UAS surveys in 2017, 2018 and 2019. Results from UAS monitoring and mapping of the distribution of 832 moving boulders in the study area over the 3-year period show that boulders located in different zones of the coast vary significantly in their mobility. The main findings reveal that the theoretical error of the volume obtained by us-ing the volume differential method is estimated as 1-3.9%, which is much smaller than the con-ventional method of estimating volume using a tape measure.

Magnetic evidence for lightning strikes on mountains in Lesotho as an important denudation agent

Contrary to previous opinion, 'frost shattering' is not the only major contributor to rock weathe... more Contrary to previous opinion, 'frost shattering' is not the only major contributor to rock weathering at mid latitudes and high elevations, more specifically along edges of bedrock escarpments. Lightning is also a significant contributor to land surface denudation. We can show this as lightning strikes on outcrops can dramatically alter the magnetic signature of rocks and is one of the main sources of noise in paleomagnetic studies. Igneous rocks in the highlands of Lesotho, southern Africa (> 3000 m elevation) provide an ideal study location, as flow lavas remain as prominent ridges that are relatively resistant to weathering. It is well known that lightning strikes can cause large remanent magnetization in rocks with little resultant variation in susceptibility. At two adjoining peaks in the Lesotho highlands, mapped freshly fractured rock correlates with areas of high magnetic intensity (remanent component), but little variation in susceptibility (related to the induced field), and is therefore a clear indicator of lightning damage. The majority of these mapped strike sites occur at the edges of topographic highs. Variations in magnetic intensity are correlated with the much lower resolution national lightning strikes dataset. These data confirm that high elevation edges of peak scarps are the focus of previous lightning strikes. This method of magnetic surveying compared with lightning strike data is a new method of confirming the locations of lightning strikes, and reduces the need for intensive paleomagnetic studies of the area to confirm remanence.

Denudation and geomorphic change in the Anthropocene; a global overview

The effects of human activity on geomorphic processes, particularly those related to denudation/s... more The effects of human activity on geomorphic processes, particularly those related to denudation/sedimentation, are investigated by reviewing case studies and global assessments covering the past few centuries. Evidence we have assembled from different parts of the world, as well as from the literature, show that certain geomorphic processes are experiencing an acceleration, especially since the mid-twentieth century. This suggests that a global geomorphic change is taking place, largely caused by anthropogenic landscape changes. Direct human-driven denudation (through activities involving excavation, transport, and accumulation of geological materials) has increased by a factor of 30 between 1950 and 2015, representing a ten-fold increase of per capita effect. Direct plus indirectly human-induced denudation (triggered by land surface alteration) is presently at least one order of magnitude greater than denudation due to purely natural processes. The activity of slope movements, which represent an important contribution to denudation, sediment generation and landscape evolution, also shows a clear intensification. Frequency of hazardous events and disasters related to slope movements (an indirect measure of process frequency) in specific regions, as well as at continental and global levels, has grown considerably, in particular after the mid-twentieth century. Intense rainstorm events are often related to slope movement occurrence, but the general increasing trend observed is not satisfactorily explained by climate.

A literature review analysis of engagement with the Nagoya Protocol, with specific application to Africa

The 2010 Nagoya Protocol is an international framework for access and benefit sharing (ABS) of th... more The 2010 Nagoya Protocol is an international framework for access and benefit sharing (ABS) of the use of genetic and biological resources, with particular focus on indigenous communities. This is especially important in Africa, where local communities have a close reliance on environmental resources and ecosystems. However, national legislation and policies commonly lag behind international agreements, and this poses challenges for legal compliance as well as practical applications. This study reviews the academic literature on the Nagoya Protocol and ABS applications, and then considers the implications of this analysis for research in Africa. Results show that there is uneven engagement with the principles of the Nagoya Protocol across different academic disciplines; local communities are sometimes sidelined in these studies; and only 8% of researchers in the literature analysed are located in Africa. Future developments should focus on ensuring national compliance with the Nagoya Protocol, and that researchers and industry work in partnership with local African communities on ABS issues.

Scientists' warning of the impacts of climate change on mountains

Mountains are highly diverse in areal extent, geological and climatic context, ecosystems and hum... more Mountains are highly diverse in areal extent, geological and climatic context, ecosystems and human activity. As such, mountain environments worldwide are particularly sensitive to the effects of anthropogenic climate change (global warming) as a result of their unique heat balance properties and the presence of climatically-sensitive snow, ice, permafrost and ecosystems. Consequently, mountain systems-in particular cryospheric ones-are currently undergoing unprecedented changes in the Anthropocene. This study identifies and discusses four of the major properties of mountains upon which anthropogenic climate change can impact, and indeed is already doing so. These properties are: the changing mountain cryosphere of glaciers and permafrost; mountain hazards and risk; mountain ecosystems and their services; and mountain communities and infrastructure. It is notable that changes in these different mountain properties do not follow a predictable trajectory of evolution in response to anthropogenic climate change. This demonstrates that different elements of mountain systems exhibit different sensitivities to forcing. The interconnections between these different properties highlight that mountains should be considered as integrated biophysical systems, of which human activity is part. Interrelationships between these mountain properties are discussed through a model of mountain socio-biophysical systems, which provides a framework for examining climate impacts and vulnerabilities. Managing the risks associated with ongoing climate change in mountains requires an integrated approach to climate change impacts monitoring and management.

Presence, Absence, Transience: The Spatiotemporalities of Sand

Sand grains are ubiquitous in the Earth’s system, and are found in different environmental settin... more Sand grains are ubiquitous in the Earth’s system, and are found in different environmental settings globally, but sand itself as a physical object has multiple conflicting meanings with respect to both its agglomeration into landforms such as sand dunes and beaches, and how sand and its dynamics have cultural significance and meaning. This study takes a transdisciplinary approach towards examining the multiple meanings of sand, focusing on sand as a spatiotemporal pheneomenon that exists in different contexts within the Earth system. The nature and spatiotemporalities of sand are framed in this study through the concepts of presence, absence and transience, which are key interpretive approaches that lie at the interface of how the physical and phenomenological worlds interact with each other. This is a new and innovative approach to understanding people–environment relationships. These concepts are then discussed using the examples of the dynamics of and values ascribed to desert dune and sandy beach landscapes, drawn from locations globally. These examples show that the dynamic geomorphic changes taking place in sand landscapes (sandscapes) by erosion and deposition (determining the presence and absence of sand in such landscapes) pose challenges for the ways in which people make sense of, locate, interact with and value these landscapes. This uncertainty that arises from constant change (the transience of sandscapes) highlights the multiple meanings that sandscapes can hold, and this represents the comforting yet also unsettling nature of sand, as a vivid symbol of human–Earth relationships.

A morphological classification of coastal forelands, with examples from South Africa

Alongshore variations in the cross-shore width, and therefore volume, of sandy beaches are import... more Alongshore variations in the cross-shore width, and therefore volume, of sandy beaches are important because these reflect spatial variability in the operation of wave- and wind-driven processes taking place both at the shoreface and in the supratidal zone. One key geomorphic signature of variations in cross-shore beach width is the development of coastal forelands. Different foreland types have been described in the literature from very specific geomorphic contexts, but hitherto there has been no overarching classification scheme that genetically links these different foreland types, or considers them in the wider context of sandy beach dynamics. In order to achieve this aim, this study maps and inventorises 87 forelands from the South African coast (~2600 km long), and classifies these into four morphological types: salients, tombolos, cuspate forelands, and ramp forelands. These foreland types have different morphological properties, reflecting the interplay of coastal erosional and depositional processes and any antecedent conditions; and a varying balance of morphodynamic controls on their development and behaviour. These include variations in wave (and to a lesser extent wind) energy, sediment supply, and the presence of bedrock outcrops of different sizes, shapes and positions along the shoreline. Analysis of foreland morphology and dynamic behaviour, based on examples from South Africa, enables a better understanding of coastal forelands globally as integrated sediment systems and responsive to the range of forcings driving coastal change.

Inland wetlands in Africa: A review of their typologies and ecosystem services

Wetlands, as one of the most productive natural ecosystems globally, have important roles in Eart... more Wetlands, as one of the most productive natural ecosystems globally, have important roles in Earth system functioning through supporting biodiversity, storing carbon, recharging groundwater and removing pollutants. They are also critical locations for providing ecosystem and environmental services and thus supporting human livelihoods, especially in Africa where inland wetlands are extensively used for agriculture and as water sources. Despite this, the Ramsar Convention classifications do not wholly describe the physical nature and properties of African inland wetlands, or the varied and interconnected ways in which different ecosystem and environmental services are manifested in them. This review critically discusses the different types and definitions of inland wetlands in Africa with particular reference to dambos, based on wetland geomorphological, hydrological and ecological properties, and then considers the entangled nature of their ecosystem services and the benefits provided to local communities. Considering these services in a more integrated way – and not as a tick-box exercise as per the Ramsar Convention – allows for a better understanding of human–environment relations in wetlands, with implications for wetland sustainability and more effective management practices.

An extended last glacial maximum in the Southern Hemisphere: A contribution to the SHeMax project

Proxy records from across the Southern Hemisphere show significant local to regional scale variab... more Proxy records from across the Southern Hemisphere show significant local to regional scale variability in climatic and environmental conditions during late Marine Isotope Stage 3 and early Marine Isotope Stage 2, prior to the global last glacial maximum (LGM; 26.5–19.0 kyr). Although not necessarily synchronous across the hemisphere, the regional signature of these pre-26.5 kyr ‘events’ suggests greater complexity of events preceding the global LGM in the Southern Hemisphere than in the North. Here we explore climatic and environmental variability across the Southern Hemisphere during two time-slices: 32 ± 1 kyr (representing the period of Southern Hemisphere summer insolation minimum) and 21 ± 1 kyr (representing the period of maximum global ice volume), based on previously published palaeoclimate proxy data. Temperatures were already approaching glacial levels across the Southern Hemisphere at 32 ± 1 kyr and minimum temperatures were attained in many records at ~21 ± 1 kyr. Furthermore, the descent into minimum temperatures occurred later in Antarctica than elsewhere in the Southern Hemisphere. Effective precipitation was more variable, with evidence for both increased and decreased moisture availability across the hemisphere during each time slice. The pattern of effective precipitation indicates that local factors likely played a more significant role in driving moisture availability compared to temperature. Our findings indicate that the onset of full-glacial conditions across the Southern Hemisphere occurred prior to the attainment of global maximum ice volume.