Forest 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.

Do elephants really never forget? What we know about elephant memory and a call for further investigation.

Despite popular culture's promotion of the elephant's ability to "never forget," there is remarkably limited empirical research on the memory capacities of any living elephant species (Asian, Elephas maximus; African savanna, Loxodonta africana; African forest, Loxodonta cyclotis). A growing body of literature on elephant cognition and behavioral ecology has provided insight into the elephant's ability to behave flexibly in changing physical and social environments, but little direct evidence of how memory might relate to this flexibility exists. In this paper, we review and discuss the potential relationships between what we know about elephant cognition and behavior and the elephants' memory for the world around them as they navigate their physical, social, and spatial environments. We also discuss future directions for investigating elephant memory and implications for such research on elephant conservation and human-elephant conflict mitigation.

Comparative study of the body proportions in Elephantidae and other large herbivorous mammals.

In this study, we aimed to achieve three objectives: (1) to precisely characterize the body plans ofElephantidae and other large herbivorous mammals; (2) based on this analysis, to determine whether the body plans of the extinct woolly mammoth (Mammuthus primigenius) and steppe mammoth (M. trogontherii) differ from those of modern-day Elephantidae: the Asian elephant (Elephas maximus), the African bush (Loxodonta africana), and forest (L. cyclotis) elephants; (3) to analyze how the body plans have changed in extant perissodactyls and proboscideans compared with their Paleogene ancestors. To accomplish this, we studied mammoth skeletons from the collections of Russian museums and compared this data with a large number of skeletons of extant elephantids, odd-toed, and even-toed ungulates, as well as their extinct relatives. We showed that three genera of Elephantidae are characterized by a homogeneous body plan, which is markedly different from other large herbivores. Elephantids break the interrelationship, that exists in artiodactyls and perissodactyls, between the total length of the head and neck on one side and the limb's segments on the other. Their limbs are very tall (inferior in this regard among large ungulates only to the giraffe), and, contrary to the other large herbivorous mammals, elongated due to the length of the proximal segments. This allows them to effectively utilize the principle of inverted pendulum (straight-legged walking) in locomotion. The biggest differences in the body plan of mammoths compared with extant elephants are a markedly larger pelvis, elongated fore- and hindlimbs (due to the increased relative length of their proximal segments), and different proportions of the skull. The body plans of plesiomorphic Paleogene proboscideans and perissodactyls differed markedly from their descendants in every body part; these differences are related, on the one hand, to the allometric growth, and on the other hand, to the advancement of the locomotor apparatus in the course of their evolution. The most notable difference in the body plan between Paleogene proboscidean Moeritherium and extant Elephantidae is the ~2-fold increase in relative limb height.

Population genetic structure and historical demography of the population of forest elephants in Côte d'Ivoire.

The population of forest elephant (Loxodonta cyclotis) has continuously declined in Côte d'Ivoire and, the remaining population largely consists of subpopulations that are fragmented and isolated. No data actually exist on the level of genetic diversity and population genetic structure of current forest elephant populations in Côte d'Ivoire. In this sense, determining genetic diversity and the underlying mechanisms of population differentiation is crucial for the initiation of effective conservation management. A total of 158 dung samples of forest elephants were collected at stage 1 of decompositions (dung pile intact, very fresh) in three Classified Forests (CF) (Bossématié, Dassioko and Port-Gauthier) in Côte d'Ivoire. A total of 101 sequences of the mitochondrial DNA control region measuring 600 base pair and 26 haplotypes were obtained. A haplotypic diversity ranging from 0.655 ± 0.050 at Bossématié and 0.859 ± 0.088 at Port Gauthier was obtained. Fifteen (15) out of 26 haplotypes observed were singletons and only the Dassioko and Port Gauthier CFs shared the same haplotypes. The strong genetic connectivity between forest elephant populations of the Dassioko and Port Gauthier CFs is supported by the grouping of these populations into a single cluster by Bayesian analysis. Although populations of L. cyclotis exhibit relatively high genetic diversity, habitat fragmentation could affect the genetic variability of current populations. Urgent measures including the reinforcement/establishment of genetic corridors and the strengthening of protection measures need to be undertaken to save the remaining populations of forest elephants in Côte d'Ivoire.

Parks can effectively protect ungulates and elephants despite a constant poaching threat

Establishing protected areas is a key element of most conservation strategies, but continuous effective management is needed to ensure that biodiversity is protected. Here we provide an evaluation of park effectiveness by quantifying changes in the abundance of the commonly occurring ungulates (bushbuck - Tragelaphus scriptus; red duiker - Cephalophus harveyi; blue duiker - Cephalophus moniticola, bushpigs - Potomochoerus larvatus, and giant forest hogs - Hylochoerus meinertzhageni), and African elephants (forest elephants - Loxodonta cyclotis, savanna elephants - Loxodonta africana, and their hybrids) in Kibale National Park, Uganda and consider the financial commitment needed to ensure protection. Following the upgrading of the protection of Kibale from a forest reserve to a national park, wildlife populations generally increased. Bushpigs are an exception and their populations appear stable. The increases of ungulate and elephant populations typically happened soon after park establishment, with the exception of the giant forest hog that only recently showed an increase. We conducted an assessment of Uganda Wildlife Authorities budget and those of the small NGOs working in the area and considered the contribution that Makerere University Biological Field Stations makes to the community. This analysis indicates that with a small budget UWA and its collaborators have been successful in protecting the park’s ungulate and elephant populations. While the past decades have demonstrated the park’s ability to conserve biodiversity with limited resources, the changing climate and mounting pressures faced by the park will necessitate significantly increased investments.

Performance of protected areas in conserving African elephants

AbstractProtected areas have been gazetted to protect natural resources and biodiversity, but evaluations of effectiveness rarely include measures of species population change. We compiled annual site‐level spending and elephant population data for 102 protected areas conserving either savannah (Loxodonta africana) or forest (Loxodonta cyclotis) elephants, which showed a median annual population decline of −0.78% across the protected areas. Site‐level population change was strongly associated with funding and government effectiveness. Annual funding deficits occurred in 78% of the protected areas, and when comparing necessary levels of annual spend to stabilize elephant populations, we estimate a US$1.5 billion annual funding deficit across all the protected areas. While financial investment can improve elephant conservation outcomes, there is still a need to identify where and how to best finance elephant poaching interventions, requiring a global commitment to improve the socioeconomic impacts of protected areas on local communities and reduce ivory demand.

Using multiscale lidar to determine variation in canopy structure from African forest elephant trails

AbstractRecently classified as a unique species by the IUCN, African forest elephants (Loxodonta cyclotis) are critically endangered due to severe poaching. With limited knowledge about their ecological role due to the dense tropical forests they inhabit in central Africa, it is unclear how the Afrotropics are influenced by elephants. Although their role as seed dispersers is well known, they may also drive large‐scale processes that determine forest structure through the creation of elephant trails and browsing the understory, allowing larger, carbon‐dense trees to succeed. Multiple scales of lidar were collected by NASA in Lopé National Park, Gabon from 2015 to 2022. Utilizing two airborne lidar datasets in an African forest elephant stronghold, detailed canopy structural information was used in conjunction with elephant trail data to determine how forest structure varies on and off trails. Forest along elephant trails displayed different structural characteristics than forested areas off trails, with lower canopy height, canopy cover, and different vertical distribution of plant density. Less plant area density was found on trails at 1 m in height, while more vegetation was found at 12 m, compared to off trail locations. Trails in forest areas with previous logging history had lower plant area in the top of the canopy. Forest elephants can be considered as “logging light” ecosystem engineers, affecting canopy structure through browsing and movement. Both airborne lidar scales were able to capture elephant impact along trails, with the high‐resolution discrete return lidar performing higher than waveform lidar.

FSC-certified forest management benefits large mammals compared to non-FSC

More than a quarter of the world’s tropical forests are exploited for timber1. Logging impacts biodiversity in these ecosystems, primarily through the creation of forest roads that facilitate hunting for wildlife over extensive areas. Forest management certification schemes such as the Forest Stewardship Council (FSC) are expected to mitigate impacts on biodiversity, but so far very little is known about the effectiveness of FSC certification because of research design challenges, predominantly limited sample sizes2,3. Here we provide this evidence by using 1.3 million camera-trap photos of 55 mammal species in 14 logging concessions in western equatorial Africa. We observed higher mammal encounter rates in FSC-certified than in non-FSC logging concessions. The effect was most pronounced for species weighing more than 10 kg and for species of high conservation priority such as the critically endangered forest elephant and western lowland gorilla. Across the whole mammal community, non-FSC concessions contained proportionally more rodents and other small species than did FSC-certified concessions. The first priority for species protection should be to maintain unlogged forests with effective law enforcement, but for logged forests our findings provide convincing data that FSC-certified forest management is less damaging to the mammal community than is non-FSC forest management. This study provides strong evidence that FSC-certified forest management or equivalently stringent requirements and controlling mechanisms should become the norm for timber extraction to avoid half-empty forests dominated by rodents and other small species.

Call combination in African forest elephants Loxodonta cyclotis.

Syntax, the combination of meaning-devoid phonemes into meaningful words, which in turn are combined in structurally and semantically complex sentences, is fundamental to the unlimited expressiveness of human languages. Studying the functions of call combinations in non-human species provides insights into the evolution of such syntactic capabilities. Here, we investigated the combination of high amplitude broadband calls with low frequency rumble vocalizations in a highly social species, the African forest elephant Loxodonta cyclotis. Rumbles play an integral role in coordinating social interactions by transmitting socially relevant information, including individual identity. By contrast, broadband calls, such as roars, are thought to function as signals of distress and urgency as they are typically produced in situations of high emotional intensity. Functional changes associated with the combination of these calls remain little understood. We found that call combinations were produced by all age-sex classes but were most prevalent in immature individuals. We found that rumbles used singularly occurred in all five investigated social contexts, whereas single broadband calls were restricted to two resource-related contexts. Call combinations also occurred in all five contexts, suggesting an increase in the functional use of broadband calls when combined with rumbles, analogous to the generativity brought about through syntax in human speech. Moreover, combining calls appeared to lead to functional shifts towards high-stake contexts. Call combinations were more likely in competition contexts compared to single rumbles, and more likely in separation contexts compared to single broadband calls. We suggest that call combination in forest elephants may aide to reduce message ambiguity in high-stake situation by simultaneously communicating distress and individual identity, which may be critical to secure access to resources, reduce the risk of injury and to reunite with or recruit the support of the family group.

Human-elephant conflict in the African rainforest landscape: crop-raiding situations and damage mitigation strategies in rural Gabon

While the conservation of forest elephants is a global concern, human-elephant conflict (HEC), especially crop-raiding by elephants, is a serious threat to both human livelihoods and conservation efforts. However, only a few studies have explored elephant crop-raiding and related damage mitigation strategies in Central Africa’s forest landscapes, which are characterized by low human and high animal densities and shifting cultivation practices. This study investigates HEC in rural Gabon, where human activities are limited, and local livelihoods are severely threatened by crop-raiding elephants. Through long-term ethnographic research and an in-depth analysis of damage mitigation practices by local people, the study unveils serious crop-raiding by elephants, leading to a significant change in the local lifestyle. Most households spend the majority of days in the field protecting crops, resulting in the village becoming almost empty. In addition to the physical burden of staying in poor living conditions, there is a considerable psychological burden for local people. Establishing effective elephant conservation systems requires understanding each local situation and evaluating the various costs to local people. To sustain livelihoods and address the challenge of HEC, it is crucial for local communities and various stakeholders to act collectively.

Unravelling the dynamics: Large mammal occupancy modelling in a West African tropical forest

AbstractThis study investigates the response of large mammal populations to human‐induced modifications in the Omo‐Shasha‐Oluwa Forest Reserves landscape. The impact of habitat alterations on species diversity and distribution remains poorly understood in this region. Over four seasons from May 2017 to April 2019, 52 sites were surveyed, revealing the presence of 12 large mammal species across six families. Maxwell's duiker exhibited the highest overall occupancy (0.897 ± 0.062), while the Forest elephant had the lowest (0.115 ± 0.043). Forest buffalo experienced the greatest increase in site occupancy (0.290 ± 0.076 to 0.358 ± 0.098), whereas the Mona monkey saw the most significant decrease (0.713 to 0.651). The study employed single‐species, multi‐season occupancy modelling, predicting colonisation and extinction events solely for the civet (ϒ = 0.347 ± 0.154; ε = 0.041 ± 0.031) and Red river hog (ϒ = 0.158 ± 0.098; ε = 0.098 ± 0.059). The likelihood of Civet cat and Red river hog colonisation increased with distance from the nearest settlement. These findings enhance our understanding of habitat characteristics influencing large mammal distribution, offering valuable insights for the conservation of these species in forest landscapes.

Early detection of human impacts using acoustic monitoring: An example with forest elephants.

The impacts of human activities and climate change on animal populations often take considerable time before they are reflected in typical measures of population health such as population size, demography, and landscape use. Earlier detection of such impacts could enhance the effectiveness of conservation strategies, particularly for species with slow population growth. Passive acoustic monitoring is increasingly used to estimate occupancy and population size, but this tool can also monitor subtle shifts in behavior that might be early indicators of changing impacts. Here we use data from an acoustic grid, monitoring 1250 km2 of forest in northern Republic of Congo, to study how forest elephants (Loxodonta cyclotis) assess risk associated with human impacts across a landscape that includes a national park as well as active and inactive logging concessions. By quantifying emerging patterns of behavior at the population level, arising from individual-based decisions, we gain an understanding of how elephants perceive their landscape along an axis of human disturbance. Forest elephants in relatively undisturbed forests are active nearly equally day and night. However, they become more nocturnal when exposed to a perceived risk such as poaching. We assessed elephant perception of risk by monitoring changes in the likelihood of nocturnal vocal activity relative to differing levels of human activity. We show that logging is perceived to be a risk on moderate time and small spatial scales, but with little effect on elephant density. However, risk avoidance persisted in areas with relatively easy access to poachers and in more open habitats where poaching has historically been concentrated. Increased nocturnal activity is a common response in many animals to human intrusion on the landscape. Provided a species is acoustically active, passive acoustic monitoring can measure changes in human impact at early stages of such change, informing management priorities.

Damage of trees by forest Elephants (Elephas maximus) in Cauvery Wildlife Sanctuary, Western Ghats, Karnataka: Are they sustainable?

Damage of trees by forest Elephants (Elephas maximus) in Cauvery Wildlife Sanctuary, Western Ghats, Karnataka: Are they sustainable?

Linking crop availability, forest elephant visitation and perceptions of human–elephant interactions in villages bordering Ivindo National Park, Gabon

AbstractFeeding by Critically Endangered forest elephants Loxodonta cyclotis in rural plantations is a conservation issue in Gabon, but studies characterizing drivers of spatiotemporal patterns of human–elephant interactions remain sparse, hindering mitigation. In this study, we use GPS tracking data from two elephants to characterize temporal patterns of village visitation, and surveys of 101 local farmers across seven villages to determine local patterns of crop planting and harvesting and of human–elephant interactions. Local farmers' perceptions of elephant visitations and empirical data on such visits were positively correlated with local crop availability. However, considering the two elephants separately revealed that the correlations were driven by just one individual, with the second elephant showing weak links between crop availability and visitation, highlighting the challenges in reliably predicting human–wildlife interactions. The most popular local perceptions of the drivers of elephant visitation were the presence of crops (53% of responses) and logging (39%). The most popular proposed interventions were letting the government find a solution (32%), killing problem elephants (30%) and providing compensation for lost crops (22%). We discuss the potential feasibility and efficacy of the proposed solutions in the context of human–elephant interactions. Future research efforts should focus on collaring elephants in zones with high potential for negative human–elephant interaction and expanding perception surveys to villages with contrasting ecological contexts (e.g. with and without logging in their surrounding forests), as these could influence local perceptions of conflicts and conservation initiatives.

Integrating local and scientific ecological knowledge to assess African forest elephant (Loxodonta cyclotis) populations in a data-deficient region, Eastern Democratic Republic of Congo

Given this need to study wildlife populations reliably, quickly and within financial and human resource constraints faced by wildlife managers, we evaluated the pooling local expert opinion (PLEO) as a tool for collecting extensive data on local animal abundance and population trends. We quantified reliability of abundance estimates derived from interviews by comparing them with those obtained from standard field-sampling protocols (distance sampling). We also explored the complementarity of these two approaches in assessing population status and distribution. We estimated there are c. 161 individuals in the selected Itombwe nature reserve and Luama hunting domain landscape covering 1,712 km2. The highly suitable elephant habitat in the Itombwe Reserve was set at 1,045.5 km2 while the largest total of low and unsuitable area was estimated to be 1,529.9 km2. Overall, this study shows that the PLEO methodology provides an effective and complementary tool to estimate forest elephant trend and habitat suitability in tropical rainforests by involving local communities in biodiversity conservation. We suggest that by incorporating the PLEO methodology into regular monitoring activity, conservation bodies can create a platform that allows for participatory wildlife monitoring and create the platform to involve local communities in elephant conservation.

African Forest elephants persist in Guinea-Bissau but require an emergency conservation plan

AbstractThe status of the forest elephant Loxodonta cyclotis in Guinea-Bissau has been in doubt since the last assessment in 2006. In 2020–2022 we carried out field surveys to update the species' status. We found elephant signs within an area of c. 1,000 km2. Microsatellite genotyping of faeces identified four males. Females could not be individually identified but their presence was confirmed by molecular sex determination. Camera trapping (2,075 camera-trap days) recorded 824 photos in 24 independent sequences, involving three males and two presumed females. The continued presence of elephants in Guinea-Bissau raises hope for the species in the region, but urgent efforts are needed to refine population range and size estimates, increase protected area coverage, and reduce ongoing and impending habitat loss. An emergency conservation action plan is a priority.

Fruit availability and human disturbance influence forest elephant group size

Fruit availability and human disturbance influence forest elephant group size

Optimising faecal sample storage and DNA extraction procedures to help the implementation of forest elephant conservation strategies

AbstractFaecal samples are an important source of genetic information for studies of wild animals. The quality and quantity of faecal DNA can, however, be affected by different factors. Our goal was to compare different dung sample storage and DNA extraction methods to optimise the quality and quantity of DNA extracted from forest elephant dung samples. Dung samples (n = 132) of forest elephants were collected in a forest area in Côte d'Ivoire. Each faecal sample was preserved in 50 mL cryotubes using five different methods: Ethanol 70%, formalin 10%, Sodium acetate, acetic acid, and formalin (SAF), dimethyl sulfoxide, and Sodium chloride (20% DMSO), and silica gel. We used the Cetyl Trimethyl Ammonium Bromide (CTAB) cationic detergent and the phenol chloroform DNA extraction procedures for comparison. DNA was successfully obtained from all 132 faecal samples using both DNA extraction methods. Regarding the total DNA extracted independently from the storage buffers, the phenol chloroform method yields a mean DNA concentration (2163.93 ± 918.62 ng/μL) sevenfold higher than that obtained with the optimised CTAB method (338.15 ± 528.54 ng/μL). Our study indicates optimised faecal sample storage and DNA extraction procedures that can help implement conservation strategies for forest elephants.

Population status and anthropogenic disturbances of forest elephants (Loxodonta cyclotis Matschie, 1900) in Nki National park and its environs, east region, Cameroon

African elephants play important roles in both the natural and human worlds: ecologically as a keystone species, economically as drivers of tourism and culturally as icons of the African continent. Increasingly, elephant populations are threatened by poaching for ivory, human-elephant conflict, habitat loss and fragmentation, and isolation of populations. This study was carried out to estimate the population of forest elephants and determine the human threats to their population. Data was collected along eleven 2 Km line transects and reconnaissance walk as well as administration of semi-structured questionnaires. Results obtained indicated a mean dung pile of 6.0 boli/Km2. Elephant density, thus, was 0.14 elephant/km2, translated to 428 (217-897) individual elephants. The main threats on elephant population with their percentage acceptance were identified to be non-respect of law enforcement (94.4%), hunting for bushmeat (92.5%), hunting for ivory (91.6%), lack of a management plan (73.8%), logging (68.2%) and road construction (43.0%). It was therefore concluded that there is a reduction in elephant population in the park from 565 in 2015 to 428 in 2021. Thus, it is recommended that increased law enforcement, surveillance and the setting up of constant and long-term monitoring programs be carried out in the park.

Not all roads are barriers: Large mammals use logging roads in a timber concession of south-eastern Cameroon

In the literature, roads are often considered to be barriers for large vertebrates. In central Africa, the creation of roads and skid trails by logging operations leads to changes in the structure of forest landscapes that could influence wildlife movements. To assess the use of logging roads by six emblematic species of the central African forests, we conducted a camera trap (CT) survey on three types of tracks (secondary roads, skid trails, and elephant paths as control) in a logging concession of south-eastern Cameroon. The relative abundance indices (RAI) of each species derived from the CT data were used in a mixed linear model to test the effects of four factors (type of track; time: day vs. night; gregariousness: alone vs. group; and time after logging: less than one year vs. between one and two years). The results showed no preference for any type of track for gorillas (Gorilla gorilla) and chimpanzees (Pan troglodytes). In contrast, significantly higher RAI on secondary roads were observed for buffalos (Syncerus caffer), forest elephants (Loxodonta cyclotis), and bongos (Tragelaphus eurycerus). For the last two, the difference was only significant if they were detected in the most recently logged areas, at night (for elephants), or alone (for bongos). We could not test for leopard (Panthera pardus) as we captured only two events. Although none of the species appear to avoid roads and skid trails, nor do they perceive them as a barrier, further studies should be conducted to increase sampling efforts over time and space to consider seasonality, vegetation growth after logging, geographical variability, and other anthropogenic influence. However, these first results reveal the importance of closing roads after logging to limit encounters between wildlife and humans and highlight the relevance of characterizing roads (type of road, width, surfacing, and canopy structure over the road) when studying their impact on wildlife.