Search Results (85)

In many developing African countries, milk safety is often managed through traditional methods such as fermentation or boiling over firewood. While these approaches reduce some microbial risks, they present critical limitations. Firewood dependency contributes to deforestation, depletion of agricultural residues, and loss of soil fertility, which, in turn, compromise environmental health and food security. Solar pasteurization provides a reliable and sustainable method for thermally inactivating pathogenic microorganisms in milk and other perishable foods at sub-boiling temperatures, preserving its nutritional quality. This study aimed to evaluate the thermal and microbial performance of a low-cost solar milk pasteurization system, hypothesized to effectively reduce microbial contaminants and retain milk quality under natural sunlight. The system was constructed using locally available materials and tailored to the climatic conditions of the Savanna ecological zone in West Africa. A flat-plate glass solar collector was integrated with a 0.15 cm thick stainless steel cylindrical milk vat, featuring a 2.2 cm hot water jacket and 0.5 cm thick aluminum foil insulation. The system was tested in Navrongo, Ghana, under ambient temperatures ranging from 30 °C to 43 °C. The pasteurizer successfully processed up to 8 L of milk per batch, achieving a maximum milk temperature of 74 °C by 14:00 GMT. Microbial analysis revealed a significant reduction in bacterial load, from 6.6 × 10⁶ CFU/mL to 1.0 × 10² CFU/mL, with complete elimination of coliforms. These results confirmed the device’s effectiveness in achieving safe pasteurization levels. The findings demonstrate that this locally built solar pasteurization system is a viable and cost-effective solution for improving milk safety in arid, electricity-limited regions. Its potential scalability also opens avenues for rural entrepreneurship in solar-powered food and water treatment technologies. Full article

The National Museum of Natural History and Science holds a historical collection of 279 small African mammal specimens (Macroscelidea and Rodentia), representing 32 species, gathered during the Portuguese colonial period in Mozambique, Angola, and Guinea-Bissau. This study examines the collection, updates the small mammal species lists for each country, and highlights its importance as a historical baseline for biodiversity research. Rodents dominate the collection, reflecting their natural abundance and diversity, while Macroscelidea are less represented. The Angolan subset of the collection has the highest number of both specimens and species represented. Mozambique is underrepresented, and the Guinea-Bissau subset offers an extensive rodent representation of the country’s inventory. The most well-represented species are Gerbilliscus leucogaster, Lemniscomys striatus, Lemniscomys griselda (from Angola), and Heliosciurus gambianus (from Guinea-Bissau). Notably, the collection includes the neo-paratype of Dasymys nudipes (from Angola). Most species are common and not currently threatened, with geographic origin corresponding to savanna and forest habitats. These findings underscore the importance of integrating historical data and current biodiversity assessments to support multidisciplinary studies on target species, regions, or countries. In this context, the collection remains a valuable key resource for advanced research on African small mammals. Full article

This study provides novel insight into herbaceous-layer dynamics across three distinct South African savanna bioregions (Central Bushveld, Lowveld, and Mopane) using a Total Count Quadrat approach to investigate species densities, community composition, diversity, and spatial patterns. A total of 196 unique herbaceous species were recorded across all bioregions. Contrary to typical expectations, our findings reveal no statistically significant differences in overall herbaceous density (ranging from 24.3 ± 2.31 to 32.0 ± 1.28 individuals/m²; F_2,6 = 1.89, p = 0.23), species richness (F_2,6 = 1.91, p = 0.23), or Shannon diversity (F_2,6 = 3.23, p = 0.11) among bioregions, suggesting a more complex interplay of environmental drivers beyond broad climatic gradients. However, there was significant within-bioregion spatial heterogeneity in density, notably in the Central Bushveld (F_2,87 = 4.96, p = 0.009) and Mopane (F_2,87 = 7.54, p < 0.001) regions, indicating important fine-scale variation, unlike in the Lowveld region (F_2,87 = 1.25, p = 0.292). Growth form analysis revealed that forbs consistently dominated species richness across all three bioregions (Central Bushveld: ~64%; Lowveld: ~70%; and Mopane: ~67%) and were also the dominant growth form by density in the Lowveld (54.3%) and Mopane (63.8%) regions. While numerical differences in grass density were observed, no statistically significant difference was found across bioregions (F_2,6 = 4.15, p = 0.07). Sedges consistently contributed a small proportion to both species richness and total density. Non-metric multidimensional scaling further revealed patterns of dispersion in herbaceous community compositions between the Lowveld and Mopane regions, with Central Bushveld communities exhibiting greater variability. These findings underscore the critical ecological importance of forbs in South African savannas, not only for biomass but also for driving herbaceous diversity and highlighting the necessity of considering fine-scale spatial variation in future ecological research and conservation strategies. Full article

Satellite data provide the spatial distributions of burned areas worldwide; assessing their accuracy and comparing burned area estimates from different products is relevant to gain insights into their reliability and sources of error. We compared BA maps derived from multispectral satellite data with different spatial resolutions, ranging from Planet (3 m) to Sentinel-2 (S2, 10–20 m), Sentinel-3 (S3, 300 m), and MODIS (250–500 m), over selected African sites for the year 2019. Planet and S2 images were processed to derive BA maps with a supervised Random Forest algorithm and used to assess the spatial agreement of the FireCCISFD20, FireCCI51, FireCCIS311, and MCD64A1 products by computing omission and commission errors, Dice Coefficient, and Relative bias. The products based on S2 images showed the greatest agreement with the very high-resolution Planet BA maps (overall Dice Coefficient was found to be greater than 80%). The coarse-resolution products showed a lower spatial agreement with reference perimeters. Among the coarse spatial resolution products, FireCCIS311 was found to outperform the others. The spatial resolution of satellite data was found to be influential on accuracy, with the omission error greater than the commission (RelB < 0) for coarser resolution BA products. The spatial patterns of burns and the vegetation type were found to be significant in the mapping accuracy, and BA detection in Sahelian savannas was found to be more accurate. This study provides insights into the variability of the spatial accuracy of different burned area products derived from very high- to coarse-resolution satellite imagery. Full article

The adoption of land cover standards is essential for resolving inconsistencies in global, regional, and national land cover datasets. This study examines the challenges associated with integrating existing datasets, including variations in land cover class definitions, classification methodologies, limited interoperability, and reduced comparability across scales. Focusing on Ghana as a case study, this research aims to develop a land cover legend and land cover map aligned with International Organization for Standardization (ISO) 19144-2 standards, evaluate the effectiveness of improving land cover classification and accuracy of data, and finally, assess the challenges and opportunities for the adoption of land cover standards. This study uses a multi-sensor remote sensing approach, integrating Sentinel-1 and Sentinel-2 optical imagery with ancillary data (elevation, slope, and aspect), to produce a national land cover dataset for 2023. Using the random forest (RF) algorithm, the land cover map was developed based on a land cover legend derived from the West African land cover reference system (WALCRS). The study also collaborates with national and international organizations to ensure the dataset meets global reporting standards for Sustainable Development Goals (SDGs), including those for land degradation neutrality. Using a survey form, stakeholders in the land cover domain were engaged globally (world), regionally (Africa), and nationally (Ghana), to assess the challenges to and opportunities for the adoption of land cover standards. The key findings reveal a diverse range of land cover types across Ghana, with cultivated rainfed areas (28.3%), closed/open forest areas (19.6%), and savanna areas (15.9%) being the most dominant classes. The classification achieved an overall accuracy of 90%, showing the robustness of the RF model for land cover mapping in a heterogeneous landscape such as Ghana. This study identified a limited familiarity with land cover standards, lack of documentation, cost implication, and complexity of standards as challenges to the adoption of land cover standards. Despite the challenges, this study highlights opportunities for adopting land cover standards, including improved data accuracy, support for decision-making, and enhanced capacity for monitoring sustainable land cover changes. The findings highlight the importance of integrating land cover standards to meet international reporting requirements and contribute to effective environmental monitoring and sustainable development initiatives. Full article

Structural changes in savanna trees vary spatially and temporally because of both biotic and abiotic drivers, as well as the complex interactions between them. Given this complexity, it is essential to monitor and quantify woody structural changes in savannas efficiently. We implemented a non-destructive approach based on Terrestrial Laser Scanning (TLS) and Quantitative Structure Models (QSMs) that offers the unique advantage of investigating changes in complex tree parameters, such as volume and branch length parameters that have not been previously reported for savanna trees. Leaf-off multi-scan TLS point clouds were acquired during the dry season, using a Riegl VZ1000 TLS, in September 2015 and October 2019 at the Skukuza flux tower in Kruger National Park, South Africa. These three-dimensional (3D) data covered an area of 15.2 ha with an average point density of 4270 points/m² (0.015°) and 1600 points/m² (0.025°) for the 2015 and 2019 clouds, respectively. Individual tree segmentation was applied on the two clouds using the comparative shortest-path algorithm in LiDAR 360(v5.4) software. We reconstructed optimized QSMs and assessed tree structural parameters such as Diameter at Breast Height (DBH), tree height, crown area, volume, and branch length at individual tree level. The DBH, tree height, crown area, and trunk volume showed significant positive correlations (R² > 0.80) between scanning periods regardless of the difference in the number of points of the matched trees. The opposite was observed for total and branch volume, total number of branches, and 1st-order branch length. As the difference in the point densities increased, the difference in the computed parameters also increased (R² < 0.63) for a high relative difference. A total of 45% of the trees present in 2015 were identified in 2019 as damaged/felled (75 trees), and the volume lost was estimated to be 83.4 m³. The results of our study showed that volume reconstruction algorithms such as TreeQSMs and high-resolution TLS datasets can be used successfully to quantify changes in the structure of savanna trees. The results of this study are key in understanding savanna ecology given its complex and dynamic nature and accurately quantifying the gains and losses that could arise from fire, drought, herbivory, and other abiotic and biotic disturbances. Full article

Robust monitoring techniques, capable of showing change in the savanna when change has occurred, are a prerequisite for better managing this ecosystem. The Step Point Method is a well-established technique in South African range surveys (Short and Morris 2016). However, it is often considered inaccurate in describing vegetation dynamics in the savanna herbaceous layer due primarily to issues with sample sizes and cover estimates, its inability to capture the spatial heterogeneity and patchy distribution typical of these ecosystems, sensitivity to observer bias, reliance on relative values and poor inclusion of sparse or less common species. This study aimed to test the effectiveness and accuracy of the Step Point Method for monitoring the herbaceous layer of savanna by comparison to absolute densities of plants. The results show that the Step Point Method only recorded 41–50% of species richness. It overestimated the relative species richness of grasses by 17.4% while underestimating that of forbs by 13.8% on average. The relative abundance of grasses was overestimated by 32.4%, while that of forbs was underestimated on average by 28.4%. Dominance was overestimated by 115.5% on average, and species diversity was underestimated by 15%. Considering these shortcomings, the Step Point Method should be used with extreme caution in studies focusing on monitoring temporal and spatial changes in veld condition and for biodiversity management. Full article

Wildfires are an intrinsic and vital driving factor in the Miombo ecosystem. Understanding fire regimes in Miombo is crucial for its ecological sustainability. Miombo is dominant in Central Mozambique, having one of the highest fire incidences in the country. This study evaluated the spatio-temporal patterns of fire regimes (intensity, seasonality, frequency and fire return interval) in the LevasFlor Forest Concession (LFC), Central Mozambique using remotely sensed data from 2001 to 2022. We conducted hotspot spatial statistics using the Getis-Ord Gi* method to assess fire distribution and patterns. The results revealed that 88% of the study area was burnt at least once from 2001 to 2022, with an average burned area of 9733 ha/year (21% of LFC’s total area). Fires were more likely to occur (74.4%) in open and deciduous Miombo types. A total of 84% of the studied area, burned in a range of 4 to 22 years of fire return interval (FRI) over the 21 assessed. Only 16% of the area was affected by high to very high FRI (1 to 4 years), with an average FRI of 4.43 years. Generally, fires are more frequent and intense in September and October. These results highlight the usefulness of remote sensing in evaluating long-term spatiotemporal fire trends for effective fire management strategies and control measures in African savanna ecosystems. Full article

Knowledge of elephant movement and grouping patterns in the wild is critical for their management and conservation. Much of these data come from GPS collar data and aerial surveys, which have provided invaluable information, but data from these methods are often limited to small groups or entire populations. Effective elephant management requires both generalized and localized methodologies. Here, we propose the expanded use of camera traps in research relating to elephant localized movements and grouping patterns as an additional tool for elephant conservation management. In this study, we use a battery-powered camera trap to provide daily high-resolution data of African savanna elephant (Loxodonta africana) grouping patterns over the course of an entire year. We present findings on the seasonal and diurnal grouping patterns of elephants at a waterhole in the northeast corner of Etosha National Park from July 2016 to June 2017. The frequency of elephant occurrences varied seasonally and diurnally across all group types (solitary male, male, family, and mixed groups), while group sizes did not vary seasonally, except for male groups. Solitary males occurred relatively equally throughout the day, while male and mixed groups occurred the most midday, and family groups occurred the most in the afternoon. Additionally, we measured the reliability of research assistants when collecting group type and group size data from the camera trap images. Intra- and inter-observer reliability was excellent among and across research assistants, highlighting the potential for non-specialist observers to have greater involvement in camera trap data collection. Our results support the use of camera trap data where GPS collars and aerial surveys are not feasible and where higher-resolution data are needed for more localized management. Finally, we discuss our experience with two different types of camera traps to highlight the pros and cons of each approach. Full article

Along with the woody plant expansion that is predicted to continue at the expense of the grassy layer is the increasing societal demand for animal protein and livestock products. Unless concerted efforts by land users, ecologists, and animal scientists are made to increase the utilization of trees and shrubs as forage, it will be impossible to meet future demand for meat and meat products. We conducted two short-term pen experiments to determine the effects of (1) supplementation with polyethylene glycol (PEG-a polymer purported to bind and neutralize the negative effects of tannins), a high-protein source (soybean meal), and a high-energy source (yellow maize grain) and (2) diet mixing (single-species vs. multispecies diets) on the intake of condensed tannin-rich woody plants (i.e., Searsia lancea, S. pyroides, and Euclea crispa) by goats. While all three forage species were used in the diet mixing experiment (Exp. 2), only E. crispa was used in the supplementation experiment (Exp. 1). Supplementing goats with energy- and protein-rich sources significantly increased the intake of E. crispa (p < 0.05), 713.4 g ± 13.5 and 760 g ± 28.9, respectively, whereas those on the control diet maintained their intake at 540.32 g ± 11.2. Although PEG tended to increase the consumption of E. crispa by goats, the observed increase was not significant (p > 0.05) from that observed in other treatments. In the diet mixing experiment, goats offered a combination of all three forage species attained substantially higher dry matter intakes compared to the goats offered these species individually (p < 0.05). While longer-term field experiments are needed in the African savannas, we postulate from the current results that management strategies that provide animals with (1) a variety of species in the diet vs. monocultures and (2) a combination of nutrient-rich and tannin-rich species may improve the ability of goats to consume chemically defended woody plants. Full article

The occurrence of extreme precipitation events always leads to a mass of disasters. In this study, based on daily precipitation data from 20 meteorological stations in Ethiopia, we performed a detailed analysis of patterns and trends of ten extreme precipitation indices during 1990–2020. Our study revealed that different topographic conditions on the Ethiopian Plateau, Ethiopian savanna and Ethiopian desert resulted in great differences in patterns and trends of extreme precipitation. Notably, extreme precipitation intensity indices (Rx1day, Rx5day, SDII) and amount indices (R95pTOT) showed significant downward trends in the eastern desert (averagely −1.0 mm/year, −3.0 mm/year, −0.25 mm day⁻¹/year, −6.0 mm/year) and upward trends in the northern plateau and southern savanna (averagely 0.3 mm/year, 0.4 mm/year, 0.05 mm day⁻¹/year, 3.0 mm/year). These implied that extreme precipitation events decreased in the eastern desert and increased in the northern plateau and southern savanna during the past thirty years. Annual trends of the CDD index were upward (0.5 to 1.9 days/year) in most of Ethiopia while those of the CWD index were close to zero in most of Ethiopia, indicating that Ethiopia faced a longer duration of drought in the past thirty years. Moreover, we revealed that the local mean temperature, local mean precipitation, Southwest Asian summer monsoon and West African summer monsoon have significant impacts on the intensity, amount and duration of extreme precipitations in Ethiopia. Full article

Crop-raiding by elephants is one of the most prevalent forms of human–elephant conflict and is increasing with the spread of agriculture into wildlife range areas. As the magnitude of conflicts between people and elephants increases across Africa and Asia, mitigating and reducing the impacts of elephant crop-raiding has become a major focus of conservation intervention. In this study, we tested the responses of semi-captive elephants to the “smelly” elephant repellent, a novel olfactory crop-raiding mitigation method. At two trial sites, in Zambia and Thailand, African elephants (Loxodonta africana) and Asian elephants (Elephas maximus) were exposed to the repellent, in order to test whether or not they entered an area protected by the repellent and whether they ate the food provided. The repellent elicited clear reactions from both study groups of elephants compared to control conditions. Generalised linear models revealed that the elephants were more alert, sniffed more, and vocalised more when they encountered the repellent. Although the repellent triggered a response, it did not prevent elephants from entering plots protected by the repellent or from eating crops, unlike in trials conducted with wild elephants. Personality played a role in responses towards the repellent, as the elephants that entered the experimental plots were bolder and more curious individuals. We conclude that, although captive environments provide controlled settings for experimental testing, the ecological validity of testing human–elephant conflict mitigation methods with captive wildlife should be strongly considered. This study also shows that understanding animal behaviour is essential for improving human–elephant coexistence and for designing deterrence mechanisms. Appreciating personality traits in elephants, especially amongst “problem” elephants who have a greater propensity to crop raid, could lead to the design of new mitigation methods designed to target these individuals. Full article

Formic acid was investigated as a potential repellant for African savanna elephants (Loxodonta africana) as a semiochemical option for managing elephant movements and interactions with human infrastructure. Formic acid is a naturally occurring compound, used as an alarm pheromone and as a defensive chemical in Formicine ants, and thus a potentially desirable option compared to introducing exogenous deterrents that are foreign to the elephants’ natural habitats. Although most elephants observed (85%) did not interact with treatments containing formic acid, of the cohort of individuals (n = 38) that did respond, the majority showed a mild to moderate avoidance response, while a small proportion of elephants were distinctly repelled when experiencing formic acid cues, in some cases causing whole herds to evacuate an area. The potential for using formic acid as an elephant repellant to modulate elephant behavior in field situations is discussed. Full article

Mechanical and chemical methods are widely used to control woody plant encroachment in many African countries. However, very little is known about the effectiveness of these control methods among woody species of different ages. We conducted a field experiment to determine the effects of different tree removal treatments (10%, 20%, 50%, 75% and 100%) and herbicide application (Picloram; 6 mL L⁻¹) on the resprouting ability and vigour of 12 woody plant species. We examined 20 plots (30 m × 30 m) that were each subjected to tree removal, followed by herbicide application on half of the stems for each plot. All the tree species in this study resprouted after cutting. The applied concentration of herbicide significantly reduced the shoot production for Ehretia rigida, Vachellia robusta and Ziziphus mucronata, with a marginal effect for Dichrostachys cinerea. The diameter of stems was an important factor in determining resprouting ability, with shoot production decreasing with increasing stem diameter. However, stem diameter did not affect shoot length and diameter for all species. We found that woody plants are more likely to resprout and survive as juveniles than as adults after cutting and that herbicide only affected four of the twelve species at a concentration of 6 mL L⁻¹. Thus, testing the amount of Picloram needed to kill certain woody species may be of importance for land users in southern African savannas. Full article

Savanna landscapes are shaped by the interactions of disturbances with land use goals. Elephant hunting in a site in Botswana, and its consequences for wildlife, people, and landscapes, are described and discussed in order to make broader generalizations about the dynamics of savanna landscapes. Change comes from alterations in tree-grass interactions, fire regimes, predator-prey relations, livestock raising, and conservation goals. Some of these implications are specific to African landscapes, but others may be apt in global contexts. Full article