African Savannah Elephants Research Articles

Survey-based inference of continental African elephant decline

Long-term quantification of temporal species trends is fundamental to the assignment of conservation status, which in turn is critical for planning and targeting management interventions. However, monitoring effort and methodologies can change over the assessment period, resulting in heterogeneous data that are difficult to interpret. Here, we develop a hierarchical, random effects Bayesian model to estimate site-level trends in density of African elephants from geographically disparate survey data. The approach treats the density trend per site as a random effect and estimates a parametric distribution of these trends for each partitioning of the data. Data were available from 475 sites, in 37 countries, between 1964 and 2016 (a total of 1,325 surveys). We implemented the model separately and in combination for the African forest (Loxodonta cyclotis) and savannah (Loxodonta africana) elephant species, as well as by region. Inference from these distributions indicates a mean site-level decline for each species over the study period, with the average forest elephant decline estimated to be more than 90% compared to 70% for the savannah elephant. In combination, there has been a mean 77% decline across all sites; but in all models, substantial heterogeneity in trends was found, with stable to increasing trends more common in southern Africa. This work provides the most comprehensive assessment undertaken on the two African elephant species, illustrating the variability in their status across populations.

Modelling Tree Allometries to Understand the Impact of African Savannah Elephant Herbivory Dynamics on the Vegetation Structure and Tree Cover Change in a Protected Area

ABSTRACTIn landscapes with high elephant density, trees often exhibit more open canopies with fewer branches and foliage due to browsing pressure. This can result in altered tree morphology, with trees exhibiting stunted growth, multiple stems or unusual branching patterns in response to repeated damage from browsing. The objectives of this research were to (i) model the vegetation structure allometries, (ii) assess the impact of African savannah elephant (Loxodonta africana) herbivory on the vegetation structure and (iii) assess tree cover change and vegetation performance over time in Mana Pools National Park in Zimbabwe. We established 26 plots of 30 × 30 m size. Selection of sampling plots was done following several steps. First, a fish net grid with 30 × 30 m polygons was created and projected on the polygon of Mana Pools National Park. The polygons for exclusion zones were then clipped from the fish net grid using the clip tool in ArcGIS Pro 3.0. Then, selection of sampling plots was done initially by stratified random sampling using the Sampling Design Tool add in for ArcGIS Pro 3.0. Landsat images for the years 2003, 2013 and 2023 were used to assess land use land cover (LULC) time series and to calculate Normalised Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) for the period. A generalised linear model (GLM) was used to analyse tree allometries. Further statistical investigations were performed using Bayesian piecewise regression (BPR) and Bayesian regression modelling (BRM). Basal area, number of stems, height, long canopy, diameter and basal circumference were all significantly different (p < 0.05) across all sampled plots. The change in growing conditions occurring as a tree grows beyond the reach of the African savannah elephant browsing indicates a natural system breakpoint. The best‐fitting models were a simple linear model and a two breakpoint model for the plant population exposed to elephant herbivory. LULC, NDVI and SAVI confirm evidence of high tree regeneration over 2 decades. Understanding the dynamics in vegetation and LULC changes is critical for effective conservation and management of the habitats for African savannah elephants, as well as for maintaining the health and resilience of forest ecosystems.

A comparison of home range estimates using the time local convex hull (T‐LoCoH) and minimum convex polygon (MCP) methods for African savannah elephants in a semi‐arid protected area

A comparison of home range estimates using the time local convex hull (T‐LoCoH) and minimum convex polygon (MCP) methods for African savannah elephants in a semi‐arid protected area

Lack of crucial information exacerbates barriers to mitigating human–elephant conflicts in rural Kenya

Abstract Crop foraging by African savannah elephants Loxodonta africana negatively affects farmer livelihoods and support for conservation, yet affordable, sustainable and practical solutions remain elusive. To inform conservation priorities, our goal was to assess the hitherto little explored relationships between farmers’ views on agricultural damage and the socio-economic factors limiting their use of elephant deterrents. We tested our hypotheses associated with the demographic categories of age, education level, years spent farming, gender, exposure to information on deterrent methods, farm size, village and relevant combinations of these factors by surveying 206 respondents across six villages in rural Kenya and analysing the resulting data using an information theoretic approach. Respondents were almost four times more likely to use deterrents if exposed to the relevant information, and almost five times more likely to do so if they had secondary education as opposed to none. Farmers with a higher level of education were five times more likely to have received information on deterrents compared to those with no formal education. Participants who had not received information on deterrents were almost three times more likely to believe that they could implement deterrent methods. Respondents who stated that they could not implement deterrents overwhelmingly cited a lack of financial resources as the reason. Overall, we found that crucial information on reducing elephant crop foraging is not reaching the relevant stakeholders, and socio-economic factors such as education and exposure to information appear to limit uptake of protective measures. These insights are important for developing mitigation strategies and supporting the livelihoods of people affected by negative human–elephant interactions, and thus for effective elephant conservation. Our findings also have broader applications for practitioners seeking to understand barriers stakeholders face in their efforts to mitigate negative interactions with wildlife.

Modelled Vegetation Structure and Abundance Confirms African Savannah Elephant‐Induced Damage Across Space in a Dry Protected Area With Diverse Vegetation

ABSTRACTThe African savannah elephant (Loxodonta africana) is an ecosystem engineer essential in determining the structure and vegetation abundance in mesic dry protected areas such as the Mana Pools National Park (MNP) in Zimbabwe. Understanding the interactions between elephants and vegetation structure is essential for effective conservation and management of savannah ecosystems. Conservation efforts often aim to balance elephant populations with the carrying capacity of their habitats to ensure the sustainability of both flora and fauna within protected areas. Therefore understanding how African savannah elephants influence vegetation structure, abundance and damage is critical for adaptive ecosystem management and wildlife conservation in mesic savannah ecosystems. This study assessed: (i) vegetation structure, (ii) abundance and (iii) evidence of elephant‐induced vegetation damage near a distance gradient to water points in MNP. A generalised linear model (GLM) was used to investigate the relationship between vegetation aspects that is structure, abundance and evidence of damage with distance from water sources. In the mesic protected MNP where African savannah elephants predominate, the modelled vegetation shape, abundance and damage exhibit spatial differences on a distant gradient towards water sources (χ2, p < 0.05). There is need for implementation of comparably, less costly, homogenous conservation measures for African savannah elephants across the artificial water pans in the MNP.

Predicting the Dry Season Habitat Occupancy of African Savannah Elephant Using Vegetation Indices and Modelling Landscape Variability in a Mesic Protected Area

ABSTRACTAfrican savannah elephants (Loxodonta africana) are key ecosystem engineers that migrate over large spatiotemporal scales foraging as they require copious amounts of food and water across habitable landscapes. Therefore a need to understand movement patterns arises in relation to vegetation type and landscape variability, moreso in forage depauparate arid areas such as Gonarezhou National Park (GNP) in Zimbabwe. The objectives of this study were to: (i) assess the performance of vegetation indices in modelling the distribution of African savannah elephants, and (ii) model future landscape variability in Gonarezhou National Park (GNP) in Zimbabwe. Maximum entropy (MaxEnt) algorithm was used to explore the relationship between vegetation indices and distribution of African savannah elephants in the GNP. The Soil Adjusted Vegetation Index (SAVI) performs better relative to other indices in modelling the distribution of African savannah elephants across all habitat types in the GNP. Cellular automata‐Artificial Neural Network (CA‐ANN) showed a significant future decrease (Kruskal Anova; p < 0.05) in landscape suitable to sustain large populations of African savannah elephants in the GNP by the year 2083. Future remote sensing reveals directional insights into the future consequences of current landscape management for African savannah elephant conservation which is a crucial in the sustainability of climate threatened arid protected areas such as the GNP.

Multimodal communication and audience directedness in the greeting behaviour of semi-captive African savannah elephants

Many species communicate by combining signals into multimodal combinations. Elephants live in multi-level societies where individuals regularly separate and reunite. Upon reunion, elephants often engage in elaborate greeting rituals, where they use vocalisations and body acts produced with different body parts and of various sensory modalities (e.g., audible, tactile). However, whether these body acts represent communicative gestures and whether elephants combine vocalisations and gestures during greeting is still unknown. Here we use separation-reunion events to explore the greeting behaviour of semi-captive elephants (Loxodonta africana). We investigate whether elephants use silent-visual, audible, and tactile gestures directing them at their audience based on their state of visual attention and how they combine these gestures with vocalisations during greeting. We show that elephants select gesture modality appropriately according to their audience’s visual attention, suggesting evidence of first-order intentional communicative use. We further show that elephants integrate vocalisations and gestures into different combinations and orders. The most frequent combination consists of rumble vocalisations with ear-flapping gestures, used most often between females. By showing that a species evolutionarily distant to our own primate lineage shows sensitivity to their audience’s visual attention in their gesturing and combines gestures with vocalisations, our study advances our understanding of the emergence of first-order intentionality and multimodal communication across taxa.

Effect of the habitat and tusks on trunk grasping techniques in African savannah elephants.

Among tetrapods, grasping is an essential function involved in many vital behaviours. The selective pressures that led to this function were widely investigated in species with prehensile hands and feet. Previous studies namely highlighted a strong effect of item properties but also of the species habitat on manual grasping behaviour. African savannah elephants (Loxodonta africana) are known to display various prehensile abilities and use their trunk in a large diversity of habitats. Composed of muscles and without a rigid structure, the trunk is a muscular hydrostat with great freedom of movement. This multitasking organ is particularly recruited for grasping food items while foraging. Yet, the diet of African savannah elephants varies widely between groups living in different habitats. Moreover, they have tusks alongside the trunk which can assist in grasping behaviours, and their tusk morphologies are known to vary considerably between groups. Therefore, in this study, we investigate the food grasping techniques used by the trunk of two elephant groups that live in different habitats: an arid study site in Etosha National Park in Namibia, and an area with consistent water presence in Kruger National Park in South Africa. We characterised the tusks profiles and compared the grasping techniques and their frequencies of use for different foods. Our results show differences in food-grasping techniques between the two groups. These differences are related to the food item property and tusk profile discrepancies highlighted between the two groups. We suggest that habitat heterogeneity, particularly aridity gaps, may induce these differences. This may reveal an optimisation of grasping types depending on habitat, food size and accessibility, as well as tusk profiles.

Social Play In African Savannah Elephants May Inform Selection Against Aggression

Abstract In social groups, competition for individual advantage is balanced with cooperation, for the collective benefit. Selection against aggression has favoured cooperation and non-aggressive competitive strategies. Because social play is a behavioural system that fluctuates between cooperation and competition, selection against aggression might have especially influenced this behaviour. African savannah elephants (Loxodonta africana) are a low aggressive species, therefore suitable to investigate this aspect. We collected all occurrences observational audio-video data on social play, aggression/threats, and affiliation on an African elephant colony housed in a 25-ha open space at Parque de la Naturaleza de Cabarceno (Cantabria, Spain) and composed of four family groups (3 immature males, 3 immature females, and 7 adult females) and two adult males. Anticipating the influence of reduced aggression, we found that social play decreased with age, persisting in adults, and that it was highest in males. Social play was associated with affiliation (informing cooperation). Indeed, individuals that were central in the social play network were also central in the affiliation network. For immature subjects, we found a correlation between social play and affiliation sociomatrices. However, such correlation was absent in adults and social play mostly occurred between families. Despite the limitations related to dealing with a small captive group, this study largely supports the idea that the features of social play in African savannah elephants may be related to low aggression. This investigation hints toward a non purely cooperative use of play, possibly as a non-aggressive interaction that accommodates different levels of cooperation and competition.

Haplotype-resolved chromosome-scale genomes of the Asian and African Savannah Elephants

The Proboscidea, which includes modern elephants, were once the largest terrestrial animals among extant species. They suffered mass extinction during the Ice Age. As a unique branch on the evolutionary tree, the Proboscidea are of great significance for the study of living animals. In this study, we generate chromosome-scale and haplotype-resolved genome assemblies for two extant Proboscidea species (Asian Elephant, Elephas maximus and African Savannah Elephant, Loxodonta africana) using Pacbio, Hi-C, and DNBSEQ technologies. The assembled genome sizes of the Asian and African Savannah Elephant are 3.38 Gb and 3.31 Gb, with scaffold N50 values of 130 Mb and 122 Mb, respectively. Using Hi-C technology ~97% of the scaffolds are anchored to 29 pseudochromosomes. Additionally, we identify ~9 Mb Y-linked sequences for each species. The high-quality genome assemblies in this study provide a valuable resource for future research on ecology, evolution, biology and conservation of Proboscidea species.

Protecting and connecting landscapes stabilizes populations of the Endangered savannah elephant.

The influence of protected areas on the growth of African savannah elephant populations is inadequately known. Across southern Africa, elephant numbers grew at 0.16% annually for the past quarter century. Locally, much depends on metapopulation dynamics-the size and connections of individual populations. Population numbers in large, connected, and strictly protected areas typically increased, were less variable from year to year, and suffered less from poaching. Conversely, populations in buffer areas that are less protected but still connected have more variation in growth from year to year. Buffer areas also differed more in their growth rates, likely due to more threats and dispersal opportunities in the face of such dangers. Isolated populations showed consistently high growth due to a lack of emigration. This suggests that "fortress" conservation generally maintains high growth, while anthropogenic-driven source-sink dynamics within connected conservation clusters drive stability in core areas and variability in buffers.

Maximum trunk tip force assessment related to trunk position and prehensile 'fingers' implication in African savannah elephants.

African elephants have a wide range of abilities using their trunk. As a muscular hydrostat, and thanks to the two finger-like processes at its tip, this proboscis can both precisely grasp and exert considerable force by wrapping. Yet few studies have attempted to quantify its distal grasping force. Thus, using a device equipped with force sensors and an automatic reward system, the trunk tip pinch force has been quantified in five captive female African savanna elephants. Results showed that the maximum pinch force of the trunk was 86.4 N, which may suggest that this part of the trunk is mainly dedicated to precision grasping. We also highlighted for the first time a difference in force between the two fingers of the trunk, with the dorsal finger predominantly stronger than the ventral finger. Finally, we showed that the position of the trunk, particularly the torsion, influences its force and distribution between the two trunk fingers. All these results are discussed in the light of the trunk's anatomy, and open up new avenues for evolutionary reflection and soft robot grippers.

Adrenal and metabolic hormones demonstrate risk-reward trade-offs for African elephants foraging in human-dominated landscapes.

A key driver of the African savannah elephant population decline is the loss of habitat and associated human-elephant conflict. Elephant physiological responses to these pressures, however, are largely unknown. To address this knowledge gap, we evaluated faecal glucocorticoid metabolite (fGCM) concentrations as an indicator of adrenal activity and faecal thyroid metabolite (fT3) concentrations as an indicator of metabolic activity in relation to land use, livestock density, and human landscape modification, while controlling for the effects of seasonality and primary productivity (measured using the normalized difference vegetation index). Our best-fit model found that fGCM concentrations to be elevated during the dry season, in areas with higher human modification index values, and those with more agropastoral activities and livestock. There was also a negative relationship between primary productivity and fGCM concentrations. We found fT3 concentrations to be higher during the wet season, in agropastoral landscapes, in locations with higher human activity, and in areas with no livestock. This study highlights how elephants balance nutritional rewards and risks in foraging decisions when using human-dominated landscapes, results that can serve to better interpret elephant behaviour at the human-wildlife interface and contribute to more insightful conservation strategies.

Space use by African savannah elephants in an arid protected area dominated by a mosaic of different vegetation

AbstractThe African savannah elephant (Loxodonta Africana) migrate in response to limiting environmental factors in arid areas. Using global positioning systems (GPS) telemetry data, we determined: (i) the dominant vegetation types used by African savannah elephants and (ii) the differences in the area occupied by dominant vegetation types in Gonarezhou National Park (GNP) in Zimbabwe. Significant spatiotemporal differences (p < 0.05) detected in vegetation types utilised by the African savannah elephant, and in the area covered by vegetation types induced a determinate foraging pattern. Global positioning system telemetry is a smart conservation tool for surveillance of movement patterns of African savannah elephants in protected areas.

A possible case of congenital tusklessness in a male African savannah elephant

A possible case of congenital tusklessness in a male African savannah elephant

Infrared barriers as a detection tool to reduce human–elephant conflicts

Elephant incursions into farms represent an important challenge for local communities and farmers living around protected areas, but also for the long‐term conservation of elephants. Early detection of elephants is a promising technique to reduce elephant presence in farms and human settlements reducing human–elephant interactions. In this study we investigated the potential of infrared barriers to detect African savannah elephants Loxodonta africana. We designed and tested battery‐operated photoelectric beam sensors in 12 locations of southern Tanzania and assessed the elephant detection accuracy through camera trapping for a total of 246 days. We obtained 1803 recordings of wildlife crossing the barriers range (30 different species of mammals and several bird and bat species). Our results show that infrared barriers, when located at 1.75–2.2 m high, detect 100% of adult elephants and ∼ 29% of subadult elephants. Giraffes were the only other wildlife species detected by the barriers. Interestingly, large vehicles were also detected, which might be helpful to prevent motorized poaching. Given the gregarious behaviour of elephant families, and the limited access for vehicles, infrared barriers may represent an interesting and cost‐effective detection system for early warning strategies in elephant‐dominated areas of Africa and Asia or for other large‐sized visitors.

Evaluating the determinants of wildlife tolerance in the Kavango-Zambezi Transfrontier Conservation Area in Zimbabwe

Human-wildlife interaction is a complex issue that has positive as well as negative implications for both humans and wildlife that share the same habitat. In this paper, we used the Wildlife Tolerance Model (WTM) as the theoretical framework to determine the factors that affect tolerance towards the African savannah elephant (Loxodonta africana), chacma baboon (Papio ursinus) and spotted hyena (Crocuta crocuta) among the Tonga indigenous people of Zimbabwe. We used structural equation modeling for the identification of causal pathways to see which variables – namely, exposure, positive and negative interactions, costs and benefits – affect tolerance. Our study finds that intangible benefits are the most significant determinants of tolerance across all three species. Contradictory to the expectations, tangible cost had no effect on the tolerance for any of the three species. We find that reducing exposure would also have a strong mediating effect on tangible and intangible costs from the three species. We discuss the roles that socio-economic and cultural factors play to help explain the differences in communities’ attitudes towards the three species. We conclude that more emphasis should be given to increasing the awareness of the intangible benefits, such as the ecosystem services provided by the species. Finally, we recommend using the WTM to help establish a mitigation strategy for the targeted communities and then conducting a Before-After-Control-Impact (BACI) study to evaluate the true impact of those mitigation strategies on the communities’ wildlife tolerance.

Genomic resources for Asian (Elephas maximus) and African savannah elephant (Loxodonta africana) conservation and health research.

We provide novel genomic resources to help understand the genomic traits involved in elephant health and to aid conservation efforts. We sequence 11 elephant genomes (5 African savannah, 6 Asian) from North American zoos, including 9 de novo assemblies. We estimate elephant germline mutation rates and reconstruct demographic histories. Finally, we provide an in-solution capture assay to genotype Asian elephants. This assay is suitable for analyzing degraded museum and noninvasive samples, such as feces and hair. The elephant genomic resources we present here should allow for more detailed and uniform studies in the future to aid elephant conservation efforts and disease research.

Elephant rewilding affects landscape openness and fauna habitat across a 92-year period.

Trophic rewilding aims to promote biodiverse self-sustaining ecosystems through the restoration of ecologically important taxa and the trophic interactions and cascades they propagate. How rewilding effects manifest across broad temporal scales will determine ecosystem states; however, our understanding of post-rewilding dynamics across longer time periods is limited. Here we show that the restoration of a megaherbivore, the African savannah elephant (Loxodonta africana), promotes landscape openness (i.e., various measures of vegetation composition/complexity) and modifies fauna habitat and that these effects continue to manifest up to 92 years after reintroduction. We conducted a space-for-time floristic survey and assessment of 17 habitat attributes (e.g., floristic diversity and cover, ground wood, tree hollows) across five comparable nature reserves in South African savannah, where elephants were reintroduced between 1927 and 2003, finding that elephant reintroduction time was positively correlated with landscape openness and some habitat attributes (e.g., large-sized tree hollows) but negatively associated with others (e.g., large-sized coarse woody debris). We then indexed elephant site occurrence between 2006 and 2018 using telemetry data and found positive associations between site occurrence and woody plant densities. Taken alongside the longer-term space-for-time survey, this suggests that elephants are attracted to dense vegetation in the short term and that this behavior increases landscape openness in the long term. Our results suggest that trophic rewilding with elephants helps promote a semi-open ecosystem structure of high importance for African biodiversity. More generally, our results suggest that megafauna restoration represents a promising tool to curb Earth's recent ecological losses and highlights the importance of considering long-term ecological responses when designing and managing rewilding projects.

Habitat conversion intensifies human elephant conflicts in the Eastern Wildlife Corridor, Ghana

Ghana was ranged by fairly large herds of elephants up until the 1970s (Douglas-Hamilton 1979). At one time elephants were found throughout the country but, as elsewhere on the continent, elephant habitat contracted during the 20th century. Today both the African savannah elephant (Loxodonta africana) and the African forest elephant (L. cyclotis) are still found, respectively, in the savannah and forest zones of Ghana. However, the populations are now confined to a few Protected Areas (PAs) and isolated remnant habitats, mainly due to human population pressure and related land use and land cover changes (AfESG 2000). Elephants are also killed illegally by poachers for the ivory trade, which dates back to ancient times (Parker 1973). By 2000, there were only eleven elephant population ranges in the country, with an estimated population of 1,000–2,000 individuals (WD 2000). These trends call for drastic and far-reaching elephant conservation efforts, including effective anti-poaching measures with more supportive legislation, and community-based land-use planning to foster harmonious human–elephant coexistence (HECx) in the country. Ghana has exhibited zeal for the conservation of the African elephant, both domestically and on the international front. Ghana was the first country to propose listing of African elephants in Appendix 1 of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). The country is also signatory to other international conventions, including the Convention on Biological Diversity (CBD), Ramsar Convention on Wetlands of International Importance, Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention) and the United Nations Framework Convention on Climate Change (UNFCCC), among others. In July 2008, Ghana entered into a bilateral cooperation agreement in the form of a memorandum of understanding (MOU) with the Republic of Burkina Faso for the purpose of conserving natural resources shared by the two countries, including savannah elephants. In 2000, the Wildlife Division of the Forestry Commission of Ghana, in collaboration with the World Wide Fund for Nature (WWF) and IUCN’s African Elephant Specialist Group (AfESG), developed an Elephant Conservation Strategy as a guide to ensure the conservation and survival of viable elephant populations and their habitats throughout the country. This strategy informed studies conducted of elephant migratory corridors by the Northern Savannah Biodiversity Conservation Project (NSBCP), under the auspices of the Global Environment Facility (GEF) and the World Bank, between 2002 and 2009. These studies identified two main elephant migratory routes between Burkina Faso and northern Ghana, which were designated the Eastern and Western Wildlife Corridors (EWWC). The forests and wildlife in the corridors are jointly managed by the Forest Services Division (FSD) and Wildlife Division (WD) of the Forestry Commission. This article provides a summary description of the EWWC, presents data on human–elephant conflict in the Eastern Wildlife Corridor, and discusses approaches to mitigate conflicts and ensure the survival of the elephant population in the corridor.