Exploring an extensive dataset to establish woody vegetation cover and composition in Kruger National Park for the late 1980s

Woody plant cover and species composition play an important role in defining the type and function of savanna ecosystems. Approximately 2000 sites in the Kruger National Park (KNP) were surveyed by F.J. Venter over a period from 1985 to 1989, recording vegetation, soil and topological characteristics. At each of these sites (approximately 20 m × 20 m each), woody vegetation cover and species were recorded using a rapid, Braun-Blanquet classification for three height classes: shrub (0.75 m – 2.50 m), brush (2.50 m – 5.50 m) and tree (> 5.50 m). The objective of this study was to re-analyse the vegetation component of the field data, with a specific focus to provide a spatially explicit, height-differentiated, benchmark dataset in terms of species occurrence, species richness and structural canopy cover. Overall, 145 different woody species were recorded in the dataset out of the 458 species documented to occur in the park. The dataset describes a woody layer dominated by a relatively small number of widely occurring species, as 24 of the most common woody species accounted for all woody species found on over 80% of all sites. The less common woody species (101) were each recorded on 20 sites or less. Species richness varied from 12 to 1 species per site. Structural canopy cover averaged 9.34%, 8.16% and 2.89% for shrub, brush and tree cover, respectively. The dataset provides a useful benchmark for woody species distribution in KNP and can be used to explore woody species and height class distributions, as well as comparison with more recent or future woody vegetation surveys. Conservation implications: The results provided evidence that large-scale, woody vegetation surveys conducted along roads offer useful ecosystem level information. However, such an approach fails to pick up less common species. The data presented here provided a useful snapshot of KNP woody vegetation structure and composition and could provide excellent opportunities for spatio-temporal comparisons

Shower water usage in Kruger National Park tourist accommodation : effectiveness of technology and information intervention to reduce use

Human freshwater consumption continues to be a growing global concern. Research and implementation of interventions on multiple fronts are required to safeguard this critical resource. Household water consumption is a significant contributor to overall freshwater use. Such indoor water use in nature-based tourism presents a challenge to this industry, but also provides opportunities to influence human behaviour and experimenting with, and mainstreaming, new technologies promoting water conservation and sustainability. Here we assess interventions to one significant source of water use (showers) in tourist accommodation in a popular nature-based tourism destination, the Kruger National Park, South Africa. Control trials utilizing information interventions (to induce behavioural change), and a novel shower technology, are implemented to identify water saving opportunities. We show that technological intervention (installation of Triton Xerophyte®) results in ∼30% overall water saving as compared to control showers. Adding water-saving infographics slightly enhances this saving, but is shown to have limited success when implemented in isolation (i.e. without the technology). In addition, we show how shower duration and water usage is related to ambient temperature, with the Triton Xerophyte® resulting in increasing water savings under cooler ambient conditions (up to ∼50% water reduction for ambient temperatures <5 °C). Encouragingly, visitors to this national park are shown to use less shower water and shower for shorter, even in control units, as compared to the general public, suggesting that these nature-based tourists may already be more mindful of water usage. Nature-based tourism agencies have a responsibility to promote water saving behaviour, and implementing technology and providing information and awareness in aid thereof may act as a catalyst for broader water-conservation in society.https://pubs.rsc.org/en/journals/journal/ewhj2023Mammal Research InstituteZoology and Entomolog

Kruger National Park research supersites: Establishing long-term research sites for cross-disciplinary, multiscaled learning

Researchers interested in studying the effects of fire or herbivory in the Kruger National Park (KNP) often focus their research activities on the experimental burn plots or herbivore exclosure camps, respectively. These are manipulated sites that apply treatments, for example annual fires or total exclusion of fire and herbivores. However, many projects aim to study or monitor patterns and processes emerging under non-manipulated conditions, typically at sites with contrasting geologies and rainfall. Yet, these sites are usually selected in a haphazard and uncoordinated manner for different projects and, as a consequence, it is often not possible to integrate datasets and knowledge. An alternative to the ever-increasing number of unrelated sites scattered across the park are the ‘KNP research supersites’ which have been earmarked to geographically focus future research effort, acting as data-rich, long-term sites for monitoring and research. In this paper, we introduced the four recently established KNP research supersites, which cover the rainfall gradient and geological contrast of the KNP, presenting their rationale, selection criteria and location, along with existing datasets that describe their herbaceous biomass, woody cover, phenology, fire history, levels of herbivory. Additional site-specific datasets, which are already available, or which are in preparation, were outlined together with details for assessing these open-source datasets online. Conservation implications: The KNP research supersites will become increasingly used for research, monitoring and remote-sensing calibration and ground-truthing purposes. Scientists are encouraged to gain from, and contribute towards, these sites, which will facilitate long-term data collection, data-sharing and co-learning and, ultimately, lead to a more integrated, multiscaled and multitemporal understanding of savannahs

The impacts of artificial light at night in Africa: Prospects for a research agenda

Artificial light at night (ALAN) has increasingly been recognised as one of the world’s most pernicious global change drivers that can negatively impact both human and environmental health. However, when compared to work elsewhere, the dearth of research into the mapping, expansion trajectories and consequences of ALAN in Africa is a surprising oversight by its research community. Here, we outline the scope of ALAN research and elucidate key areas in which the African research community could usefully accelerate work in this field. These areas particularly relate to how African conditions present underappreciated caveats to the quantification of ALAN, that the continent experiences unique challenges associated with ALAN, and that these also pose scientific opportunities to understanding its health and environmental impacts. As Africa is still relatively free from the high levels of ALAN found elsewhere, exciting possibilities exist to shape the continent’s developmental trajectories to mitigate ALAN impacts and help ensure the prosperity of its people and environment. Significance: We show that the African research community can usefully accelerate work into understudied aspects of ALAN, which demonstrably impacts human and environmental health. Africa presents a unique, and in places challenging, research environment to advance understanding of this global change driver

Rainfall, geology and landscape position generate large-scale spatiotemporal fire pattern heterogeneity in an African savanna

Fire is considered a critical management tool in fire prone landscapes. Often studies and policies relating to fire focus on why and how the fire regime should be managed, often neglecting to subsequently evaluate management’s ability to achieve these objectives over long temporal and large spatial scales. This study explores to what extent the long-term spatio-temporal fire patterns recorded in the Kruger National Park, South Africa has been influenced by management policies and to what extent it was dictated by underlying variability in the abiotic template. This was done using a spatially explicit fire-scar database from 1941 to 2006 across the 2 million hectare Park. Fire extent (hectares burnt per annum) (i) is correlated with rainfall cycles (ii) exhibits no long-term trend and (iii) is largely non-responsive to prevailing fire management policies. Rainfall, geology and distance from the closest perennial river and the interactions between these variables influence large-scale fire pattern heterogeneity: areas with higher rainfall, on basaltic substrates and far from rivers are more fire prone and have less heterogeneous fire regimes than areas with lower rainfall, on granitic substrates and closer to rivers. This study is the first to illustrate that under a range of rainfall and geological conditions, perennial rivers influence long-term, landscape-scale fire patterns well beyond the riparian zone (typically up to 15 km from the river). It was concluded that despite fire management policies which historically aimed for largely homogeneous fire return regimes, spatially and temporally heterogeneous patterns have emerged. This is primarily because of differences in rainfall, geology and distance from perennial rivers. We postulate that large-scale spatio-temporal fire pattern heterogeneity is implicit to heterogeneous savannas, even under largely homogenizing fire policies. Management should be informed by these patterns, embracing the natural heterogeneity-producing template. We therefore suggest that management actions will be better directed when operating at appropriate scales, nested within the broader implicit landscape patterns, and when focusing on fire regime parameters over which they have more influence (e.g. fire season).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1600-0587hb201

Spatio-temporal mixed pixel analysis of savanna ecosystems : a review

Reliable estimates of savanna vegetation constituents (i.e., woody and herbaceous vegetation) are essential as they are both responders and drivers of global change. The savanna is a highly heterogenous biome with high variability in land cover types while also being very dynamic at both temporal and spatial scales. To understand the spatial-temporal dynamics of savannas, using Earth Observation (EO) data for mixed-pixel analysis is crucial. Mixed pixel analysis provides detailed land cover data at a sub-pixel level which are essential for conservation purposes, understanding food supply for herbivores, quantifying environmental change, such as bush encroachment, and fuel availability essential for understanding fire dynamics, and for accurate estimation of savanna biomass. This review paper consulted 197 studies employing mixed-pixel analysis in savanna ecosystems. The review indicates that studies have so far attempted to resolve the savanna mixed-pixel issues by using mainly coarse resolution data, such as Terra-Aqua MODIS and AVHRR and medium resolution Landsat, to provide fractional cover data. Hence, there is a lack of spatio-temporal mixed-pixel analysis for savannas at high spatial resolutions. Methods used for mixed-pixel analysis include parametric and non-parametric methods which range from pixel-unmixing models, such as linear spectral mixture analysis (SMA), time series decomposition, empirical methods to link the green vegetation parameters with Vegetation Indices (VIs), and machine learning methods, such as regression trees (RT) and random forests (RF). Most studies were undertaken at local and regional scale, highlighting a research gap for savanna mixed pixel studies at national, continental, and global level. Parametric methods for modeling spatio-temporal mixed pixel analysis were preferred for coarse to medium resolution remote sensing data, while non-parametric methods were preferred for very high to high spatial resolution data. The review indicates a gap for long time series spatio-temporal mixed-pixel analysis of savannas using high resolution data at various scales. There is potential to harmonize the available low resolution EO data with new high-resolution sensors to provide long time series of the savanna mixed pixel, which, according to this review, is missing.The Deutscher Akademischer Austauschdienst and the Federal Ministry of Education and Research (BMBF) within the framework of the Strategy “Research for Sustainability” (FONA).http://www.mdpi.com/journal/remotesensingpm2022Geography, Geoinformatics and Meteorolog

Unsustainable fuelwood extraction from South African savannas

Wood and charcoal supply the majority of sub-Saharan Africa’s rural energy needs. The long-term supply of fuelwood is in jeopardy given high consumption rates. Using airborne light detection and ranging (LiDAR), we mapped and investigated savanna aboveground biomass across contrasting land uses, ranging from densely populated communal areas to highly protected areas in the Lowveld savannas of South Africa. We combined the LiDAR observations with socio-economic data, biomass production rates and fuelwood consumption rates in a supply–demand model to predict future fuelwood availability. LiDAR-based biomass maps revealed disturbance gradients around settlements up to 1.5 km, corresponding to the maximum distance walked to collect fuelwood. At current levels of fuelwood consumption (67% of households use fuelwood exclusively, with a 2% annual reduction), we calculate that biomass in the study area will be exhausted within thirteen years. We also show that it will require a 15% annual reduction in consumption for eight years to a level of 20% of households using fuelwood before the reduction in biomass appears to stabilize to sustainable levels. The severity of dwindling fuelwood reserves in African savannas underscores the importance of providing affordable energy for rural economic development.The CSIR researchers were funded by the CSIR Strategic Research Panel and the Department of Science and Technology’s Earth Observation Unit. SUCSES study (Sustainability in Communal Socio-Ecological Systems) which provided data on fuelwood use in Justicia was funded by the South African National Research Foundation. The airborne campaign and analysis was funded by the Andrew Mellon Foundation.http://iopscience.iop.org/1748-9326am201

Reflecting on research produced after more than 60 years of exclosures in the Kruger National Park

All data, in this case works of literature reviewed have been summarised in Online Appendix 2.Herbivores are a main driver of ecosystem patterns and processes in semi-arid savannas, with their effects clearly observed when they are excluded from landscapes. Starting in the 1960s, various herbivore exclosures have been erected in the Kruger National Park (KNP), for research and management purposes. These exclosures vary from very small (1 m2) to relatively large (almost 900 ha), from short-term (single growing season) to long-term (e.g. some of the exclosures were erected more than 60 years ago), and are located on different geologies and across a rainfall gradient. We provide a summary of the history and specifications of various exclosures. This is followed by a systematic overview of mostly peer-reviewed literature resulting from using KNP exclosures as research sites. These 75 articles cover research on soils, vegetation dynamics, herbivore exclusion on other faunal groups and disease. We provide general patterns and mechanisms in a synthesis section, and end with recommendations to increase research outputs and productivity for future exclosure experiments. CONSERVATION IMPLICATIONS : Herbivore exclosures in the KNP have become global research platforms, that have helped in the training of ecologists, veterinarians and field biologists, and have provided valuable insights into savanna dynamics that would otherwise have been hard to gain. In an age of dwindling conservation funding, we make the case for the value added by exclosures and make recommendations for their continued use as learning tools in complex African savannas.South African Environment Observation Network (SAEON).http://www.koedoe.co.zaam2023Paraclinical Science