South African Environmental Observation Network
South African Environmental Observation Network
Date | Speaker | Node | Topic/Title | Abstract | |
|---|---|---|---|---|---|
7 Aug 2020 | Jasper Slingsby | Fynbos Node | Global change is a complex topic. Even more so when overlain on an ecosystem with highly complex natural dynamics. Discerning the signal of change from the natural noise, or making projections for ecosystems under an uncertain future, are desperately needed to inform management and policy. This requires innovative ecological and statistical approaches. Here I present some of the complexities and some of the solutions my collaborators and I have been working on for Fynbos - from field surveys to satellites and mechanistic models. Many open questions and challenges remain, and our current solutions are far from perfect. With this talk I hope to pique your interest and encourage you to join us and play in this stimulating and rewarding space and/or encourage you to consider similarities or differences in the ecosystems you are most familiar with. | ||
4 Sep 2020 | Hayden Wilson, Caroline Mfopa, Marc Pienaar | uLwazi Node | The BioEnergy atlas for South Africa aims to provide information in support of the BioEnergy industry. Assessing the sustainability of establishing a BioEnergy industry in South Africa is dependent on realistic assessments of feedstock availability, cost of feedstock transport, conversion costs and market access. Additionally, technology options for BioEnergy production need to be assessed in relation to competing energy options in order to determine which options meet management objectives for energy provision, water security, job creation and social justice.This presentation outlines the approaches used by the data science team at uLwazi in order to address some of these complex issues. | ||
2 Oct 2020 | Xolisa Dlomo | Elwandle Node | Upwelling is the process that brings cold, nutrient-rich deep water towards the surface, thereby enhancing marine ecosystems through increased primary production. Winds, Coriolis Effect and Ekman Transport are the main external forces that drive upwelling. Substantial economic benefits are realized in areas where this physical process affects coastal ecosystems. Spatial and temporal variability in regimes of coastal upwelling may have profound effects on the distribution and local dynamics of coastal marine populations and entire communities. Currently available mesoscale indices for upwelling intensity lack the resolution needed to characterize and compare inner-shelf upwelling regimes at small spatial scales, which is often required to test relevant hypotheses in ecology, conservation, and management. We present local, quantitative indices of thermal variability, whose pattern across sites is largely driven by variation in coastal upwelling intensity at scales of a few kilometers. Index calculations were based on hourly records of in situ underwater depth-averaged temperatures, gathered at 6 sites in St. Francis Bay, and at 8 sites in Algoa Bay. Several univariate metrics were calculated using daily series of temperature anomalies, and combined to produce a multivariate ordination of sites (Multivariate Upwelling Zone Index of Cooling, MUZIC) that allowed us to compare sites across regions. Upwelling-induced variability at the scales documented here can have significant consequences on the ecology of coastal ecosystems. The basic data requirements (i.e. SST/ UTR time series) and the simplicity of calculation make these indices a useful tool to apply at a large number of sites around the world, and to examine the generality of community and population-level responses to physical forcing. | ||
6 Nov 2020 | Julia Glenday | Fynbos Node | Catchment-scale hydrological models are regularly used to inform water resources planning and catchment management decisions. These models necessarily reduce complex and dynamic hydrological processes in soils, vegetation, aquifers, channels, into sets of equations, logic statements, and parameter values. This seminar focuses on approaches used to calculate evapotranspiration (ET) in these models. An overview of algorithms, parameters, and methods of discretising space in a few commonly used modelling tools in South Africa will be presented to spark discussion. Model algorithms are a balance between our understanding of how a process works, levels of available data, and computational practicalities. These are changing all the time! We'd like to start a discussion between hydrologists, ecologists, ecophysiologists, micro-meteorologists, remote-sensers, and other interested '-gists' about ways our research and updated knowledge could improve estimation of ET within catchment-models. Please come ready to engage, thinking like a plant or your favorite biome! | ||
4 Dec 2020 | Jenny Jackson-Veitch | Egagasini Node | South Africa's turbulent Oceans: diving deeper with ocean models | South Africa’s contrasting dry, arid west coast and lush, green east coast are the result of the very different processes of the adjacent oceans. The warm, narrow and fast-flowing Agulhas Current off the east coast is one of the worlds major western boundary currents, while the cool Benguela Current system off the west coast is one of the four major eastern boundary systems. South Africa’s position in the global ocean is unique in that it is the only place where an eastern and western boundary system directly interact. This interaction produces a tremendous amount of turbulence in the southern Benguela system and has important ecosystem implications. In this seminar I will discuss novel ways in which numerical models are used in order to better understand an environment, so vast and dynamic, that it is difficult to sample in a spatially and temporally cohesive manner. Please join us to find out why your biome needs the ocean and how numerical models are used to fill the gaps. | |
22 Jan 2021 | Tony Swemmer | Ndlovu Node | The thickening of savannas with trees and shrubs. Does it really matter, and why has it happened? | Savanna ecosystems throughout the world have experienced various degrees of thickening over the past century, with large increases in the cover of trees and shrubs over vast areas that were previously open and dominated by grasses.Mulitple causes have been put forward to explain this so-called 'bush encroachment', with evidence supporting them varying according in different ecosytems and different parts of the world. Disruption of natural fire and herbivory regimes, changes in climate and increasing levels of atmospheric CO2 may all play a role. Despite decades of research the exact causes in any particular savanna are still not well understood. In constrast to plethora of studies on the causes of woody plant thickening, there are relatively few studies on the consequences of bush encroachment. Is widely accepted that the increases of trees and shrubs have led to losses of grass productivity and reduced biodiversity, but this is rarely supported with empirical evidence. This presentation will give an overview of research conducted by the SAEON Ndlovu Node on the causes and consequences of bush encroachment. This includes: 1) a long-term demographic studies that aims to determine causes of encroachment in drier savannas where fire does not play a role, and 2) the use of bush clearing experiments to understand the impacts of trees and shrubs on productivity and biodiversity | |
5 Feb 2021 | Manish Ramjeawon | Grasslands Node | Up to 75% of the population in Africa rely on groundwater for daily use and this percentage is even higher in the Maputaland Coastal Plain (MCP) located in the north-east of KwaZulu-Natal. Groundwater plays a vital role in the ecology of the region, as wetlands, peatlands and lakes such as Lake Sibayi and the Kosi Bay Lakes, are predominately groundwater driven. The region is an important conservation area, including the iSimangaliso Wetland Park, a World Heritage site with several RAMSAR sites. In recent years a decrease in precipitation, an increase in abstraction and a growth in commercial forestry area have resulted in a decline in groundwater levels for the MCP. Previous studies have indicated that between 2004 and 2015, boreholes located in the north eastern part of the MCP, near the Tembe and Mbazwana communities, experienced a decline of between 0.7 m and 2.7 m, while areas in the south such as Richards Bay experienced a reduction in groundwater levels of between 0.7 m and 6.3 m for the same time period. Monitoring boreholes only provide point-based measurements of groundwater level change and are not evenly distributed across the MCP. Added to this is the lack of data to convert groundwater level to groundwater storage. The Gravity Recovery and Climate Experiment (GRACE) satellite-based product has been successfully applied in many studies to determine groundwater storage change over large regions. This presentation highlights the potential of GRACE to determine groundwater storage change in the primary aquifer located in the MCP. | ||
5 March 2021 | Justin Du Toit | Arid Lands Node | The eastern Karoo of South Africa is an ecotonal zone between the Nama-Karoo and semi-arid grasslands to the east. Vegetation includes two characteristic layers – a grass layer comprising perennial and annual predominantly tufted species, and a dwarf-shrub layer comprising succulent and non-succulent perennial species. Paleo records indicate that dominance between these two life forms has fluctuated over time. Since the mid-1800s, herbivore biomass has increased by orders of magnitude with the introduction of commercial livestock agriculture. Concomitantly, observations over the past century, and more, showed a deterioration of ecosystem health, with decreases in grassiness effecting an eastward encroachment, or biome shift, of the Nama-Karoo into the grasslands. Fast-forward to present-day and the opposite has arguably occurred: grasses have marched westwards, and much of the ecotone is better described as shrubby grassland than as Nama-Karoo shrubland. Using data from various long-term experiments and opportunistic studies conducted at the Grootfontein Agricultural Development Institute, we examine the relative effects of rainfall amount and seasonality, livestock grazing systems and stocking rate, and fire to explain grass/shrub interactions in the area, and make predictions about what might drive biome boundaries in the future. | ||
9 Apr 2021 | Zach Smith | uLwazi Node | The SAEON Data Portal (catalogue.saeon.ac.za) is a search engine comprising a variety of open source software to present SAEON's data offerings to the world. In this talk I'll demonstrate some of the functionality and features of the portal from a user perspective, before exploring some of the current and proposed back-end architecture and the implications for future functionality. Feedback welcome! | ||
7 May 2021 | Phumlile Cotiyane-Pondo | Elwandle Node | Epilithic diatoms along the coast of South Africa: Insights from baseline studies | Despite the rich information on the taxonomy of marine benthic diatoms of South Africa curated by Prof. MH Giffen, the knowledge on their composition, diversity, spatio-temporal variations, and ecology around the coast of South Africa remains limited. This presentation will provide an overview of the recent benthic (epilithic) diatoms research at the Elwandle Node, showing results obtained from large and small geographical scale studies, revealing highly variable epilithic diatom abundances, species richness, and a patchy distribution along the coastline. Secondly, epilithic diatoms are known and used as indicators of water quality in freshwater systems. Can this be applied to marine waters? Given the susceptibility of our coastal marine waters to pollution, the potential use of epilithic diatoms for monitoring purposes has recently been investigated. Results have illustrated the rapid temporal variation of epilithic diatom assemblages in relation to environmental conditions. The use of diatoms as potential indicators of change along the coastline will be discussed. | |
11 Jun 2021 | Robert Skelton | Fynbos Node | Drought tolerance in diverse temperate plants: solutions to long-standing problems | My research seeks to address these primary challenges by examining fundamental physiological mechanisms underlying broader plant processes and responses, with a particular emphasis on functionally and ecologically diverse plant taxa occurring in Mediterranean-type ecosystems. A fundamental difficulty of my work is finding meaningful ways to test critical hypotheses about the different types of responses plants might demonstrate to environmental stresses in natural communities. I address this through a novel combination of detailed, innovative physiological measurements made within a laboratory setting and in situ experimental manipulations and long-term monitoring observations. Specifically, I incorporate data of plant functional traits with results from comparative plant physiology, experimental manipulations of abiotic stresses and long-term monitoring of in situ plant functionality during natural disturbance events. In this seminar I will highlight some recent advances that have emerged from my research, including a novel conceptual framework for quantifying plant drought tolerance, and solutions to long-standing problems in the field of plant hydraulics. I will demonstrate how these advances can improve our ability to predict lags in plant recovery from drought, forecast plant vulnerability to future drought, and prioritize biological groups and areas of conservation concern. | |
2 Jul 2021 | Nicole du Plessis and Erika Brown | Egagasini Node | Ecosystem Accounting and Ocean Accounts: What? Why? Who? and How? | Ocean Accounting is a component of the UN Natural Capital Accounting & Valuation of Ecosystem Services Project (led by Stats SA and SANBI nationally) which aims to assist the participating partner countries to advance the knowledge agenda on environmental and ecosystem accounting and initiate pilot testing of the System of Environmental-Economic Accounting (SEEA) and Ecosystem Accounting (EA), with an aim to improve the management of natural biotic resources, ecosystems and their services at the national level as well as mainstreaming biodiversity and ecosystems in national level policy, planning and implementation. South Africa is one of five countries participating in this project. | |
6 Aug 2021 | Marlize Muller | Ndlovu Node | Drought effects on floristic diversity in the threatened Woodbush Granite Grassland of South Africa | SAEON Egagasini, Elwandle and uLwazi Nodes are participating as part of the recently established NRF Communities of Practice - ‘Western Indian Ocean: Assessing the applicability of the ocean-accounts framework’ to trial part of the OAF within South Africa. | |
3 Sep 2021 | Paul Gordijn | Grasslands Node | This study assessed land use and land cover change (LULCC) over contrasting tenure systems in the ±1000 km2 Cathkin area of the biodiversity rich uKhahlamba Drakensberg; wherein communal, private and protected land tenures exist. In this long-term study, the success of detecting secondary grassland (e.g., vegetated old fields) was maximized by using the earliest available, from 1945, and most recent high resolution (±0.5 m GSD) orthophotos from 2016, for visual classification of land cover. Once disturbed by agricultural activities such as cultivation, grassland plant diversity is not known to recover. Over seventy years, 25% of the 647 km2 untransformed grassland was lost. Grassland was most stable under protected tenure where only 4.6% was transformed; 36% and 48% of communal land and private grasslands, respectively, were transformed by 2016. The main transitions away from grassland included transitions to cultivation (largely in private lands), degraded-vegetated areas (i.e., old fields) and plantations. Outside protected areas, Hierarchical Generalized Additive Modelling of grassland transformation revealed that by including land tenure, in addition to abiotic and settlement density predictors, the amount of explained variance increased by 11.4%. In general, flatter, wetter and lower elevations were more vulnerable to transformation, however, these dynamics have changed over time reflecting ingrained socio-ecological legacies. The limited remaining grasslands in foothill communal and private areas are critical habitat and ‘climate corridors’ for future species migrations under global change. Erosion, particularly in communal areas, signals an existing threat to grassland functioning and biodiversity. Indigenous and alien woody ingression into grassland pose significant threats to remaining grassland biodiversity. | ||
1 Oct 2021 | Gina Arena | Arid Lands Node | The overarching drivers of early 20th century dryland degradation in South Africa have been attributed to high stocking rates and overgrazing by domestic livestock. In response to these concerns, appropriate research and government interventions were implemented to address rangeland and livestock mismanagement. However, the role of long-term climate trends as a driver of semiarid vegetation change was poorly understood, particularly for changes occurring at the interface of the Nama-Karoo and Grassland biomes where shrubland encroachment could be detected along a gradient of increasing annual rainfall. It is this gradient that controls the natural biome transition from shrub-dominance to grass-dominance. However, the prediction of shrubland encroachment was refuted when research in the early 1990s revealed that the vegetation of this region (known as the ‘eastern Karoo’) had undergone an increase in grass cover; a trend that persisted into the early 2000s. Findings indicated that an increase in annual rainfall drove the increase in grass cover, but the generality of this relationship across the broader rainfall gradient of the biome transition had not been examined. In addition to rainfall, grazing by domestic livestock has also influenced the relative proportion of grasses and shrubs in the eastern Karoo. While other studies have alluded to changes in land use, few data have been presented and the relative influence of land use change has usually been under-estimated. The availability of historical vegetation surveys and landscape photographs, climate station records and magisterial district livestock censuses makes it possible to develop a more comprehensive synthesis of how vegetation has changed across the rainfall gradient in order to address questions around biome shifts. The PhD study, therefore, aimed to determine whether a biome shift is related to a broader shift in the climate regime through the assessment of long-term vegetation change along the rainfall gradient, in relation to climate and land use change since the early 20th century. | ||
5 Nov 2021 | Athi Mfikili | Elwandle Node | Foraminifera are single-celled micro-organisms with a shell test that is either secreted (i.e., carbonate, organic or siliceous) and/or agglutinated with foreign particles. Unlike their counterparts, diatoms, foraminifera are exclusively found in marine environments, often found floating in the water column (planktonic) or living on the sea floor or estuarine environments such as salt marshes (benthic). Foraminifera have an evolutionary history that extends back to the Cambrian (i.e., > 500 Ma) and have evolved since then with approximately 60,000 fossil and modern species validly recognised. To date, there are over 16,000 living foraminiferal species belonging to 1691 genera, making this group one the most abundant microfossils in the marine realm. Although foraminifera have a cosmopolitan distribution throughout the entire marine realm, the individual taxa are restricted to specific environmental niches, e.g. benthic species occur in the shallow continental margin and intertidal areas, such as salt marshes, whereas planktonic species are exclusively found in open waters of the ocean. | ||
10 Dec 2021 | Melissa Schmitt and Keenan Stears | Ndlovu Node | Savannas are structurally heterogenous ecosystems and the spatial and temporal variation in this structure is influenced by both biotic (e.g., herbivory) and abiotic (e.g., fire, climate) factors. This heterogeneity provides diverse niches for wildlife to occupy, thereby contributing to the diversity of patterns and processes synonymous with savanna systems. However, under current conditions of anthropogenic disturbance, both local and global drivers are resulting in increased density of woody plants in savannas through processes known as woody plant densification and encroachment. An increase in woody plant cover causes heterogenous savannas to shift to more homogenous landscapes. To combat this increase in woody plant cover, land managers are implementing various vegetation management practices, including large-scale tree clearing, to reduce woody plant cover. Changes in vegetation structural heterogeneity, whether through management practices or increases in woody plant cover, are likely to influence the large mammal community via strong linkages between herbivores, vegetation structural heterogeneity, and the trade-off between predation risk and food rewards. Despite this, there are surprisingly few studies that quantify how the herbivore community responds to large-scale changes in woody plant cover. Thus, we first aimed to model habitat use by herbivores at the landscape scale as a function of woody plant cover, and then use the habitat use model to predict how climate-induced changes to vegetation may alter herbivore distributions. Finally, we employed a model-based clustering approach to understand herbivore community responses to extensive vegetation management (i.e., tree clearing). | ||
| 21 Jan 2022 | Glenn Moncrieff | Fynbos Node | The simultaneous rise of computing power, explosion of ecological data, and advancement of machine learning have created a wealth of new opportunities for monitoring vegetation at very large scales with low latency. I highlight research conducted by SAEON's fynbos node combining machine learning and data on vegetation distribution, abundance and function to improve vegetation monitoring capabilities. These examples include using object detection to locate rare tree species in aerial imagery, mapping land cover change in near-realtime from satellite imagery, and automated detection of hydraulic failure in plants under water stress. Our rich and unique ecosystems and large archive of freely available environmental datasets that are well suited to the application of machine learning methods present a great strategic opportunity to conduct cutting-edge research that is of societal relevance. | ||
| 4 Feb 2022 | Laura Braby | Egagasini Node | Rough seas - never before seen measurements of the Agulhas Current | Seasonal changes in temperature and salinity across the Agulhas Current are not well understood because there have been limited hydrographic data collected in this region during austral winter. Weather and swell conditions have been known to limit operations at sea, as well as other obstacles including hydrographic winch capabilities. In this study, we use a decade worth of observations over the same transect of the Agulhas Current at 34 °S, including the first winter cross sections collected across the Agulhas System Climate Array (ASCA) line as part of the South African SEAmester programme (https://seamester.co.za/). These sections are able to capture features in the upper water column and over the continental shelf that are unresolved by the ASCA mooring array. Two full crossings and one partial crossing were occupied by the SA Agulhas II during the winters of 2016, 2018 and 2019 and we exploit this data to investigate any seasonal changes in water mass properties and transports within the Agulhas Current for the first time. | |
4 March 2022 | Rowena Harrison | Grasslands Node | Gaining insights into the hydropedological characteristics of three Afromontane catchments | The overall aim of my PhD is to understand how the movement of dissolved organic carbon (DOC) is affected by the hydropedological character of a catchment. Gaining an understanding of the internal processes that control the way water moves through a catchment is the first important step in achieving this. We used a digital soil mapping tool, the Arc Soil Inference Engine (ArcSIE) in the Cathedral Peak research catchments, with the aim of creating an understanding of the hydropedological behaviour of the soils of three of these research catchments. Once we had successfully created these maps, we used them together with a combination of measured hydraulic properties of the soils to improve the accuracy of SWAT+ hydrological models simulated for these catchments. We set up two identical SWAT+ models for each catchment and then changed the specific lateral time inputs for one of the models, based on information from the hydropedological maps as well as the hydraulic properties of the soils. This improved the modelling accuracy in all statistical parameters used, R2, PBIAS, ST DEV, NSE and KGE. The study highlighted that relevant soil information, based on reliable site-specific data, is essential in hydrological modelling. It also helped me to gain an insight into how water moves through the catchments, and this is now being used to understand the processes that control DOC movement. | |
1 April 2022 | Maletsatsi Mohapi | Arid Lands Node | Soil and geomorphological characterisation of selected ephemeral pans in the Northern Cape Province | About 50% of wetlands in South Africa are either lost or threatened through anthropogenic activities – a situation that is exacerbated by limited research on their importance and biodiversity. Their variation results due to inherent geomorphology including: soil properties, parent material, topography, organisms, and climatic conditions. South Africa’s climatic conditions promote extensive occurrence of ephemeral wetlands in the Northern Cape Province. These ephemeral wetlands are essential for water supply and purification, flood reduction, groundwater recharge and discharge, erosion, socio-cultural significance and education. Therefore, rehabilitation, conservation and maintenance of these wetlands must be prioritised. The aim of this study was to investigate the soil physico-chemical properties, environmental context and their interaction within and between the ephemeral pans and their geomorphic provinces. Soil samples were collected from the crust and soil horizon in 98 ephemeral pans from four geomorphic provinces: the Kalahari, Bushmanland, Ghaap Plateau, and Upper Karoo. These soil samples were analysed for soil pH, EC, soluble and exchangeable cations, CEC, P, Fe, Mn, and texture. The environmental context including wetland types, parent material, vegetation, topography and climate were determined from the land type data and Environmental Potential Atlas of South Africa shape files, using both ArcMap and QGIS GIS interfaces. The physico-chemical and environmental context interactions were compared using ANOVA and homogeneous subsets. The results indicated that all regions consisted of alkaline soils (pH mostly >7.5). Most geomorphic provinces were saline (EC >4 dS m-1), except for the Ghaap Plateau geomorphic province which had non-saline soils (EC <0.11 dS m-1). The majority of the soil clay minerals were deduced to be kaolinite, since the CEC of clay was less than 10 cmolc kg-1 clay. Plant available phosphorus was higher in other geomorphic provinces as compared to Ghaap Plateau geomorphic province. The free Fe content in the soil was higher as compared to the Mn oxides content except for the soils in the Ghaap Plateau geomorphic province. The Upper Karoo, Bushmanland and Kalahari geomorphic provinces showed similar soil properties compared to the Ghaap Plateau. The environmental context results indicated that Kalahari and Bushmanland geomorphic provinces had more wetlands as compared to the Ghaap Plateau and Upper Karoo geomorphic provinces. Gordonia Duneveld vegetation was dominant in the Kalahari, while Bushmanland Basin Shrubland vegetation was dominant in the Bushmanland. Ghaap Plateau Vaalbosveld vegetation was dominant in the Ghaap Plateau and Upper Karoo. Pebbly calcareous conglomerate mudstone and sandstone geology was predominantly underlying the Kalahari and Upper Karoo geomorphic provinces. The Bushmanland geomorphic province is mainly underlain by shale and migmatitic quartz-feldspar, while the Ghaap Plateau geomorphic province is underlain by dolomite. The Ghaap Plateau geomorphic province have the highest elevation and steepest slope compared to Bushmanland, Kalahari, and Upper Karoo geomorphic provinces. All geomorphic provinces except the Upper Karoo had a linear curvature (-0.3 and 0.3). The Northern Cape Province has mean annual temperatures below 20°C and mean annual rainfall below 448 mm. In comparison, the soil properties and environmental context interaction indicated that all pans differed significantly within and between the geomorphic provinces. Pan soils within the Kalahari geomorphic province differed the least from each other, while pans in the Bushmanland, Ghaap Plateau, and Upper Karoo geomorphic provinces differed significantly from each other in terms of almost all the soil and environmental properties studied. The significant differences observed among the four geomorphic provinces showed that the physico-chemical properties and environmental context do distinguish within and between the geomorphic provinces should therefore have an effect on the classification of ephemeral pans. Finally, this study demonstrated that the soil properties and environmental context are crucial in understanding the behaviour and biodiversity observed in ephemeral pans and that all pans are not created equal. These results can also be used to improve the identification and delineation of ephemeral pans in the Northern Cape Province. Future research should include other soil properties such as organic matter, total nitrogen, organic carbon, hydraulic conductivity. Based on data presented here, pans should also be carefully selected according to their requisite properties for further analyses. | |
6 May 2022 | Hayden Wilson | uLwazi Node | With the advent of powerful mobile devices, in-field data collection has become increasingly accessible and integrated. Technologies such as XForrm allow for end users with familiarity in excel to easily design and deploy web applications to mobile devices, allowing for standardised field applications to be deployed to multiple devices. These applications are responsive and allow for both online and offline data submissions. Within SAEON, as the number of instruments deployed and sites that are being monitored increases, there is an increasing administrative burden being placed on technicians to service and maintain equipment that has been deployed into the field. Additionally, there is a need to maintain detailed field records, notes and metadata so that data provenance is maintained. Previously, this has been achieved through a combination of field notes and lengthy spreadsheets that are maintained by the technicians, however, these systems become increasingly onerous to maintain as the complexity of the systems that are deployed to the field increases. Additionally, as these systems rely on spreadsheets, version control of the spreadsheets itself adds to the technicians administrative load. Furthermore, due to the spatial extent of our monitoring sites and the varied service schedule associated with the different instrument types, field trip planning and instrument service scheduling needs to be performed in an automated fashion. This presentation will showcase the operational information system that is being developed for the Shallow Marine Coastal Research Infrastructure (SMCRI) and discuss how the various aspects of the system are integrated with existing workflows to provide technicians with a system for standardised operational data collection. The systems behind the SMCRI Operational Information system are scalable and can be adapted to a variety of use cases, allowing for novel use cases to be developed within SAEON for both scientific and operational data collection. | ||
3 June 2022 | Shirley Parker-Nance | Elwandle Node | BELTER the way forward: a new LTER platform to inform on benthic change. | The Shallow Marine and Coastal Research Infrastructure (SMCRI) Benthic Ecosystem Long Term Ecological Research (BELTER) platform joins a suite of SAEON LTER platforms designed to observe environmental change. The focus is to report on marine benthic biodiversity, community structure, species abundance and distribution and their response to environmental variables, especially those related to climate change, temporally and spatially. Still in its infancy, BELTER is built on research conducted over the last decade which informed on best practices, implementation, management, and maintenance of this new national platform in line with SAEON’s mandate. Please join us for an informative talk on BELTER and a colourful introduction to the benthic reef biota of SAEON Elwandle Coastal Node’s Algoa Bay Sentinel Site. | |
1 July 2022 | Faith Jumbi | Fynbos Node | Understanding the impacts of land cover change on landscape flow pathways in critical water source areas for improved modelling and resource management' | Land use and cover types and changes thereof influences a variety of landscape surface and subsurface properties and processes, which combined determine the net impact on water resources. Numerical catchment models aim to represent the many interacting processes and can be used to predict changes in streamflow due to changes in land cover. However, high levels of uncertainty remain, largely because there are very few cases in which changes across the multiple contributing processes have been measured in the field in South African systems. To achieve this understanding, detect changes and reduce uncertainty, long-term hydrological monitoring is crucial. SAEON manages some long-term research catchments such as Cathedral Peak in the Drakensberg Mountains of KZN and Jonkershoek in the Cape Fold Mountains of the Western Cape, which provide a unique opportunity to describe impacts of cover changes on surface runoff, infiltration into soils, interflow, groundwater recharge, and groundwater discharge to streams. I shall be giving a talk on our research focus for the two catchments aimed at improving our understanding of water movement and distribution in these critical water source areas as any changes in their hydrological responses could have significant social, economic and environmental consequences. | |
5 Aug 2022 | Dr Lara Atkinson | Egagasini Node | A Benthic Trawl Experiment: Measuring change in a southern Benguela slope after cessation of trawling | ||
2 Sept 2022 | Dave Thompson | Ndlovu Node | |||
7 Oct 2022 | Sue van Rensburg | Grasslands Node | The Lake Sibaya catchment within catchment W70A is a unique wetland-rich, groundwater driven system with no surface rivers importing water into it. It is entirely dependent on localized rainfall for recharge. This Strategic Ground Water Source Area (SWSA) resource, on which local communities rely, has been declining over the last 20 years. Competition for water for human consumption, the environment, tourism, agriculture and forestry are increasing. Recent studies have indicated a combination of below average rainfall and forestry are contributing to this decline. While people in the region are aware that forestry has a negative effect on the water table, the existing conditions and perceptions make it very difficult to identify and shift towards attractive economic alternatives. We are currently undertaking a WRC funding project that aims to use a social ecological systems approach to develop a decision support tool that explores the net economic and environmental consequences of different economic and land-use choices under different climate scenarios as an initial step in transgressing perceived constraints. The intention is to use this as an engagement tool, working with communities to co-create awareness regarding the interactions of climate, land use and the water resource on the net economic well-being of the region. We report on the upfront multidisciplinary integration required to develop a system-wide resource economics model, which incorporates appropriately scaled climatological, landcover and hydrological components to assess the net impact of current and future land use and climate on this sensitive region. Results from engagements with community leaders on challenges, economic activities and aspirational land use scenarios are presented. These point towards potential self determined actionable alternatives for the region. Preliminary analysis from household surveys demonstrate commonalities as well as divergent responses relating to geographical position and access to alterative economic activities, such as ecotourism operations, with the system. | ||
4 Nov 2022 | Marc Pienaar | uLwazi Node | A global assessment of the mobilisation of freshwater biodiversity data via GBIF | Freshwater species are considered highly threatened globally, but we still have insufficient information to support a global assessment of the current status, trends, and gaps in our knowledge. The Global Biodiversity Information Facility (GBIF) is one of the key (largest and freely accessible) global repositories of species observations used to inform global assessments. GBIF information has been used at global and continental scales for analysing patterns of freshwater biodiversity, but there has not been a global assessment of the patterns of mobilisation of freshwater biodiversity data through GBIF. As a part of a Freshwater Biodiversity Data Landscape Project aimed at identifying some of the critical issues around data mobilisation in the freshwater biodiversity space through GBIF, we explore the structure of GBIF, the taxonomic scope of data currently held in GBIF, and the cost of accurately identifying freshwater species and various ways to extract the data. We focus on the fields used for tagging species and investigate the ease of extraction. To achieve this, we used published checklists of freshwater taxa where these were available or published assessments of the diversity of these groups where lists were unavailable. We selected a subset of relevant Darwin Core attributes that were useful to characterise the freshwater biodiversity data in each taxonomic group and report on preliminary findings of the global picture of data mobilisation on freshwater biodiversity from GBIF. | |
2 Dec 2022 | Mfundo Bizani | Elwandle Node | |||
3 Feb 2023 | Colleenur Seymour | Arid Lands Node | Woody structure, particularly that created by large trees, is crucial to savanna biodiversity pattern and process. On Kalahari sands with annual rainfall < 400 mm, camelthorns (Vachellia (Acacia) erioloba) are the only trees to grow to any great height, and have been found to be keystone species. Over the summer of 2003- 4, we assessed growth of 120 V. erioloba saplings with four treatments that were combinations of exclusion of herbivores or additional water. These treatments were then removed, but many of the saplings were still marked. We were therefore able to find and measure changes in vertical and horizontal canopy in 2019 (15 years later) for 67 of the saplings used in the original study. Studies have contended that it is only the fastest growing individuals that contribute to the final population of large trees. We therefore also tested whether the individuals that were the fastest growing in the original study were the same individuals that were the fastest growing in the 2003-2004 season. Height increase was extremely variable between individuals, but mean increase over 15 years was only 45.4 mm, similar to that measured for the 2003-2004 growing season (43.1 mm). Mean horizontal canopy showed far greater growth (mean 120.2 mm over 15 years, compared with 7.12 mm over 2003-4) than vertical growth. Individuals that had shown the fastest increase in horizontal canopy in 2003-4 tended to be the same individuals that grew fastest over the following 15 years, but even the highest “achievers” showed increases of only 47.2 mm and 37.5 mm.year-1 in average horizontal canopy extent and height, respectively. This study demonstrates the insights that long term studies yield, particularly in arid systems. Many individuals may be trapped in the “sapling” class, and could take decades to become large trees. Woody sapling growth was not cumulative, and modelling studies in savannas should be cautious in extrapolating growth from one season to several years. | ||
2 March 2023 | Glenn Moncrieff | Fynbos Node | Accessing SAEON observational data through the saeonobsr R Package | In this talk, I will showcase the different ways to access data from the South African Environmental Observation Network (SAEON) using its Observations Database. I will start by introducing the SAEON Observations Database, its structure, and data products. I will then demonstrate how to access SAEON data using the web portal and its graphical user interface. Next, I will show how to access SAEON data programmatically using the Observations Database API. I will demonstrate how to authenticate and connect to the API, how to search and retrieve data using API endpoints, and how to process the returned data in different formats. Finally, I will introduce a newly developed R package, saeonobsr, that provides a streamlined interface to access SAEON data from within R. I will demonstrate how to install and use the package to search, retrieve, and process SAEON data in R. This enables users to integrate SAEON data into existing scientific data workflows. I will end by discussing some of the current limitations to SAEON data and challenges involved in getting data into the hands of users, and how these are being addressed in future developments. | |
30 March 2023 | Philile Emelda Mvula | Egagasini Node | Describing the Agulhas Bank annual cycle using in-situ observations | Over the 40+ years that South Africa has conducted offshore expeditions, a lot of work has been done on the Agulhas Bank. The Agulhas Bank is a broad, shallow part of the South African continental shelf south of Port Elizabeth, it encompasses the shelf and coastal regions. The Agulhas Bank supports a large diversity of commercially valuable fish ranging from pelagic to demersal. Its annual cycle is characterised by a series of physical and biogeochemical processes that have important implications for regional and global ocean circulation, climate variability, and ecosystem productivity. During an offshore expedition in 2016, a rocky ridge was found in the Eastern Agulhas Bank. The ridge is found approximately ~40km offshore of Cape St Francis in a fishing area named chalk line grounds, where kingklip has been trawled for decades hence why it is termed the Kingklip Ridge. For our research based on characterising the environment around the kingklip ridge, we set out to first answer the question: - Can we create an annual cycle of the oceanographic environment around the Agulhas Bank with the in-situ data that has been collected to date? To answer this question, we used in-situ data collected between 1990 and 2020 from various monitoring programs to characterize the annual cycle of the Agulhas Bank. Our analysis focused on temperature, chlorophyll-a, and current velocity data from ship-based measurements. | |
4 May 2023 | James Blignaut | Ndlovu Node | In this presentation we reflect on a selection of the outcomes of a three-year DFFE/NRM funded project that ASSET Research conducted in collaboration with SAEON. The study focused on the development of a web-based systems dynamic model to enable users to gauge the plausible benefits of restoration as calibrated by means of historic evidence. To enable this calibration, a database of all known peer-reviewed papers pertaining to the benefits and the costs of restoration was developed. This enabled an evidence-based reflection as to whether restoration pays, and under which circumstances. It was observed that, for the most part, the costs were proportionately higher than the benefits at the lower quartiles, but at higher quartiles the benefits were proportionately higher. This asymmetry in the quartiles is also evident among the different ecosystems; the benefit of restoration varies much among these. Using the values as per the database it was possible to develop i) project-based, ii) district-level and iii) national-level systems dynamic models to assist in decision-making and resource allocation. | ||
1 June 2023 | Mkholo (aka khulu) Maseko | Grasslands Node | Using new data in previously developed Groundwater models - does it work? | Drastic declines in Lake Sibaya water levels have been observed over the past 2 decades with a drop from 19 m MSL in the early 2000’s to 15 m MSL in 2022. The groundwater-dependent catchment of Lake Sibaya located in uMhlabuyalingana (KwaZulu-Natal) has experienced the combined influence of forestry plantations and below average rainfall over the past two decades, placing significant stress on the groundwater system which is exacerbated by the absence of rivers flowing into the catchment. To increase confidence in the relative attribution of known causes of declines and provide future scenarios due to climate and land-use in the area, this study produced a status quo groundwater model to be used in providing future scenario simulations of groundwater and lake water levels. The end goal of this study is to advise water resources management in the Lake Sibaya groundwater catchment, as part of an inter-disciplinary study funded by the WRC and carried out by SAEON. A previously developed MODFLOW groundwater model for the area was updated based on reviewed and extended hydrological input datasets, as well as more accurate land-use and land cover (LULC) change data. An adequate representation of lake water levels as a response variable were simulated and the model was carried forth to provide a no forestry plantation scenario. In July of 2020, the no forestry plantation scenario had a water level simulation that was 1.8 m MSL higher than the status quo scenario, therefore, supporting the influence of below average rainfall on the system. Wet and dry future scenario simulations are being developed and the analysis of these scenarios, and potentially others as well, will be provided during the presentation. | |
6 July 2023 | Mark Jacobson | uLwazi Node | The SAEON Open Data Platform (ODP) is an assemblage of databases, services and web applications that facilitate the preservation, publication and discovery of earth observation and environmental data in South Africa. This perspective on the ODP is elaborated in detail in SAEON’s application (currently in review) for the ODP to be certified as a trustworthy data repository under the CoreTrustSeal banner. From a systems perspective, the ODP is a publishing service. It provides a metadata deposition API enabling data producers to describe and register their data, and a metadata catalogue API enabling data consumers to find and access those data. The ODP is integrated with various services within and outside the SAEON ecosystem which provide data preservation and data discovery capabilities. In this seminar, we explore the information architecture that underpins the ODP. We dive into the curation workflow, and see how an extensible tagging model facilitates rapid development of value-added features to the metadata publication pipeline. We look at how the generic model of a catalogue enables us to plan and implement integrations with any number and variety of data discovery applications locally and globally - including the SAEON Data Portal, the GEOSS platform and DataCite. And we consider how the generic model of an archive (representing a data producer) - seen through the lens of the exemplary SAEON Observations Database - can help us to better understand the challenges that SAEON faces in terms of data integration and publication. | ||
3 Aug 2023 | Helga van Coller | Ndlovu Node | The importance of forbs in semi-arid savanna conservation, management, and research | Semi-arid savannas are commonly described as having ecosystem types with strongly seasonal plant communities which, in their natural state, have a relatively continuous herbaceous layer and a discontinuous woody component. This herbaceous layer consists of grasses and forbs (wildflowers). Given that the grass component functions as the main source of food for grazers and domestic livestock, assessments of range conditions in semi-arid savannas are largely based on dominant palatable grass species. Consequently, forbs are poorly represented in definitions, range condition assessments, and ecological studies of savanna ecosystems. Furthermore, less attention has been given to forbs and grasses as separate functional entities which are floristically, morphologically, and physiologically distinct. Dr Helga van Coller – a professional development programme postdoctoral fellow, studies the ecology of herbaceous communities, particularly in nutrient hotspots in South African savannas. Her postgraduate research focused on the dynamics of forbs and grasses in eutrophic sodic areas in a typically dystrophic savanna. These areas are considered nutrient hotspots since their nutrient-rich vegetation is intensely utilised by herbivores. This research provided a better understanding of the ecosystem services and functions that forbs provide in these important biogeochemical hotspots. Her current postdoctoral research explores the herbaceous plant communities and nutrient cycling associated with another important source of nutrients in savannas, being the decomposition of the carcasses of megaherbivores. This research forms part of a larger research consortium aiming to answer the overarching question: How do megacarcasses influence terrestrial ecosystem processes? In her talk, Helga will share her knowledge on the various ways in which forbs are important, both floristically and ecologically, and reflect on the rationale of including this life form in conservation, management and research of savanna, and other ecosystems. | |
5 Oct 2023 | Lucienne Human | Elwandle Node | The water quality of the Knysna Estuary – A water and sediment biogeochemistry perspective | The Knysna Estuary is an estuarine bay that is permanently open to the sea. It has been classified as South Africa’s most important estuary in terms of its conservation priority. This status is mostly owed to its biodiversity importance, which is based on fish, birds, plants and invertebrates. In 2014/2015 a large bloom of opportunistic macroalgae, with Ulva lactuca as the dominant species, covered the lower reach of Knysna Estuary. The occurrence of an opportunistic species is globally considered a sign of eutrophication. The aims of this study were to determine the impact of the bloom on the Zostera capensis beds and investigate why the bloom persisted in the lower reach of the estuary. Changes in vegetation cover were measured along five permanent line transects in the intertidal zone. Water column samples were collected for nutrient analysis and benthic chambers were deployed in Ashmead Channel to investigate the flux of nutrients from the sediment. The results showed that there was a decrease in Z. capensis abundance, which had been displaced by the algal bloom. Recycled nutrients specifically, ammonium and soluble reactive phosphorus, from the sediment and input from a nearby wastewater treatment works acted as a consistent source of nutrients that enabled the bloom to persist in Ashmead Channel. Considering the nutrient input from the sediment of Ashmead, a broader study was initiated to investigate the benthic nutrient fluxes at the sediment water interface in the greater estuary. The sediment in the Upper Estuary, Lagoon and Bay acted as a source of NH4 with a rate of 100–300 μmol m−2 day−1 N, and soluble reactive phosphorus (SRP) with a rate of 15 μmol m−2 day−1 P, whereas that of Ashmead channel exceeded these rates by far. The sediment acted as a sink for NO3 − with fluxes of between −200 and 100 μmol m−2 h−1. Benthic nutrient fluxes in the estuary were positively related with sediment organic content and silt. The sediment fluxes of the great estuary are of concern because they already reflects that of eutrophic system. Nutrient fluxes in the Ashmead channel were significantly greater than the other regions because of the anoxic sediment, reduced flushing and a legacy of pollutant and organic matter retention. This condition can only be improved by removing wastewater input and dredging. Such drastic interventions are necessary to improve the health of South Africa’s top ranked estuary in terms of biodiversity importance. | |
7 Dec 2023 | Wynand Calitz | Arid Lands Node | Using phenology for long-term ecological observations: a case study | The importance of climatic conditions on influencing vegetation has been well documented and understanding these effects allow us to make predictions and prepare for future harsh conditions. South Africa is considered to be a mostly arid country but despite its arid status there is still much to learn about species responses to these conditions. The Karoo, which covers 30% of South Africa, is a great place to investigate plant responses to aridity as it experiences severe drought conditions and irregular rainfall. Phenological studies have been used for centuries, particularly in agriculture, and are useful to determine species-level responses to climate among other long-term variations. A previous study of phenology at the Tierberg Karoo Research Centre (now Tierberg Long-Term Ecological Research), focussed on how life form and landscape location influenced growth and flowering. In 2017 SAEON started a new phenological study to investigate the long-term phenology of five plant species (Ruschia spinosa, Osteospermum sinuatum, Pteronia pallens, Drosanthemum praecultum, and Galenia fruticosa). Ten plots with five replicates of each species (250 individuals in total) were observed at least once a month. Over the course of 6 years, including a significant dry period, 35% of individuals had died. The most notable species results were that R. spinosa had no fatalities and that G. fruticosa suffered 86% mortality. We also show the influence of rainfall seasonality on plant phenology. All species showed considerable growth and flowering after good rains irrespective of season, however there are still clear trends in the phenology. All of the observed species flowered in spring with fruits forming near the end of spring and being ripe in summer. There were cases where individuals flowered after rain events, but the flowers would often wilt if the rain was not substantial or was followed by high temperatures. Growth for R. spinosa occurred in small amounts throughout the year but the strongest growth was seen during winter months, particularly when there were good rain. Pteronia pallens had highest growth during the autumn months and D. praecultum during late summer. Galenia fruticosa showed highest growth only after really good rainfall. The O. sinuatum showed the greatest variability in growth, strongly correlated to rainfall events, and even seemingly dead individuals would resprout after rain events. These data are valuable in determining which species are drought-resistant as adult plants, however as no seedling emergence data were collected during the phenology study it cannot inform population ecology of the study species. | |
1 Feb 2024 | Tammy Morris | Egagasini Node | Ocean observations for Southern Africa: Fantastic robots and where to deploy them! | The Southern Hemisphere remains under-resourced with regards to ocean observations. Yet, near-real time measurements of both surface and subsurface ocean parameters are critical for our understanding of short-term weather patterns, long-term climate change, extreme ocean phenomena, such as marine heatwaves and tropical cyclones, and their impacts on society, food security and ocean health, to name a few. In the last few decades, ocean observing infrastructure has developed in leaps and bounds, particularly with regards to autonomous robots such as Argo floats and buoyancy gliders. These infrastructure allow for data acquisition offshore in regions where vessels may not always have access, and for extended periods of time. Coupling these autonomous technologies with high-resolution research vessel surveys using CTDs and plankton nets, along with strategically placed delayed-mode moored observations, creates a detailed picture of the ocean environment. South Africa is ideally placed in the crossroads of three ocean basins and three massive and distinct ocean boundary currents. Observations need to be made in such a way that they complement modelling studies and operational activities, such as global weather forecast models, provide insights to unique ocean processes and are able, to some degree, provide the information needed to mitigate against extreme weather and ocean phenomena. So where should we deploy ocean observing infrastructure to provide the best bang for our buck? In this presentation we explore the possibilities within the boundary currents around South Africa, look at existing initiatives undertaken by various South African teams, and try to work out where the gaps are. | |
7 March 2024 | Annabelle Cardoso | Bioscapes | Integrating Biodiversity Science with Remote Sensing: The Biodiversity Survey of the Cape (BioSCape) | This seminar will give an overview of the BioSCape project, including an introduction to its expected datasets. BioSCape is NASA's first biodiversity-focused integrated airborne field campaign. It took place in South Africa in Oct-Nov 2023 and investigates the structure, function, and composition of ecosystems, and how and why they are changing in time and space. BioSCape's airborne dataset is unprecedented in its instrument combination and level of detail, with near complete coverage of the electromagnetic spectrum at high resolution and coincident full-waveform lidar acquisitions. BioSCape's field datasets quantify the diversity of plant communities including alien invasives and kelp, phytoplankton functional types, phylogenetic histories, eDNA in watersheds, bird and frog acoustics, plant functional and spectral traits, blue carbon, and in-water radiometry. BioSCape is committed to facilitating Open Science and all datasets will be delivered to one of NASA's Distributed Archive and Analysis Centers. | |
4 April 2024 | Tsitsi Maponga | Ndlovu Node | Mistletoe Twists - Are mistletoes shaping semi-arid savanna plant ecosystems | Mistletoes are hemi-parasitic plants that form an intimate connection through a haustorium, which facilitates the effective uptake of nutrients and water by the mistletoe from their hosts. Mistletoes have a significant impact on the composition and dynamics of ecosystems where they are found. Some of these impacts can be negative for the host; for instance, mistletoes can induce negative ecophysiological impacts on host tree performance by compromising their hosts’ size, competitive edge, and reproduction. For example, our previous work has shown that mistletoes negatively impact the reproduction capacities of their Vachellia karroo hosts in the semi-arid savannas of Zimbabwe. Currently, we are investigating how the leaf traits of the host tree, Sclerocarya birrea, vary across a rainfall gradient and level of mistletoe infection in the communal rangelands of the Bushbuckridge area in Mpumalanga, South Africa. Nonetheless, our previous studies have also demonstrated how mistletoes positively alter the physical and chemical environment, i.e., nutrient availability and soil moisture, in their immediate vicinity through their nutrient-rich leaf litter. They increase nutrient availability to both hosts and non-host species by having a high leaf turn-over and leaves with low resorption efficiency at senescence. These characteristics ensure the addition of nutrients that would have otherwise been absent or not returned to the soil system. Subsequently, our studies show that mistletoe parasitism can potentially shift the competitive balance from dominant host tree species to non-host subordinate plants, thereby changing the plant composition and productivity in an area. Our studies have also demonstrated how the presence of mistletoes at varying degrees of infection severity has a positive impact on trees' understory productivity. Therefore, this seminar will discuss our previous and current work on how • Mistletoes contribute to understory nutrients and create nutrient hotspots. • Mistletoes facilitate differences in understory biomass and plant species composition, creating biodiversity and productivity hotspots. • Mistletoes result in differences in the reproductive capacities of Vachellia karroo trees. • Mistletoes cause variation in leaf traits of the host Sclerocarya birrea. The positive and negative effects of hemi-parasitic plants clearly show the twisted nature of mistletoes. As small as they are and as fun as it is to kiss beneath mistletoes at Christmas, the twist is that mistletoes have disproportionate effects on the ecosystems in which they occur. |