Population structure and behaviour of crop-raiding elephants in Kibale National Park, Uganda

We examined patterns of crop raiding by elephants across gender and age classes in relation to elephant life history and sociobiology and estimated the quantitative contribution of crops to elephant diet in Kibale National Park (KNP). Elephant dung‐boli sizes were used to estimate age and sex, while the presence of crop remains in the dung of crop‐raiding elephants was used as evidence of repeated raiding. To estimate the expected proportion of elephants raiding per age class, the age distribution of raiders was compared with the age distribution of all KNP elephants. Elephants raiding crops were predominantly males. They began raiding in expected proportions at 10–14 years while a higher than expected proportion raided crops at 20–24 years. These results suggest that crop raiding is initiated at an age when male elephants leave their families and a large proportion of elephants raid when they are approaching reproductive competition. Evidence from dung of crop raiders, suggests that repeated raiding increases with age. Crop raiders derived 38% of their daily forage from the short time spent raiding, consistent with expectations of foraging theory. Males may be more likely to learn crop raiding because they are socially more independent and experience intense mating competition than females.     

The influence of lunar cycles on crop‐raiding elephants; evidence for risk avoidance

Long‐term solutions to crop raiding by elephants (Loxodonta africana) should be based on an understanding of their behaviour and ecology. The real and perceived risks from humans have been shown to affect elephant behaviour. This is evidenced by elephants predominantly raiding crops at night, avoiding the height of human activity. If such human avoidance behaviours are apparent, it might also be expected that elephants avoid risks associated with higher visibility and increased human activity as may occur during the full moon. However, elephant nocturnal crop‐raiding behaviour in relation to lunar cycles has largely been a neglected factor in studies of human–elephant interactions. In this study around Mikumi National Park, Tanzania, we apply circular statistics in this context for the first time to show a significant decrease in crop raiding during the full moon and apply this method retrospectively to data from another site in West Africa with similar results. Additionally, a greater proportion of farms raided was guarded during the full moon than any other moon phase. Our results indicate that variations in crop raiding with lunar phase could be a general feature of elephant behaviour and thus could be used to design and time mitigation efforts.     

Mitigating crop raiding by forest elephants and baboons at Kibale National Park

In Africa, most protected forests are in densely human-dominated landscapes where human–wildlife conflict is intense. We documented farmer perceptions and responses to crop-raiding wildlife from Kibale National Park, Uganda. Crop raiding was mostly (95%) by baboons (Papio anubis) and elephants (Loxodonta africana). While the financial loss caused by baboons and elephants did not differ, elephants were perceived as more damaging. Guarding and trenches were perceived as the most effective deterrent strategies for baboons and elephants, respectively. Distance from the park boundary and household income were significantly associated with a greater likelihood of crop raiding. Distance from the park, household head age and the species that raided crops, influenced whether a household applied one or more deterrent strategies. Households headed by women or older adults were most vulnerable, experiencing greater losses to raiding. Patterns of human–wildlife conflict around Kibale forest are complex, but the extent of crop damage was mostly determined by distance from the park and farm socio-economic status and thus their ability to mitigate or deter raiding. Managing crop raiding requires collaboration between the park and affected farmers to ensure that mutually managed deterrent methods, such as trenching (elephants) and guarding (baboons), are effectively shared, applied and maintained.     

Demography of a population with a long history of poaching and the utility of the individual identification technique as a tool for monitoring intermittently studied elephant populations

In many elephant populations in Africa, adverse effects of poaching including altered age and sex structure and long calving intervals continue to negatively impact the rate of recovery. The study reported here characterized the demographic status of the elephant population in Meru National Park, Kenya, so as to determine the size, age and sex structure, and calving interval of the population and to compare its demographic parameters against those from the relatively stable elephant population at Amboseli. Additionally, a demographic study conducted 7 years earlier enabled us to determine the demographic performance of the population and to explicitly test the utility of the individual identification technique in monitoring intermittently studied populations. We found 392 elephants in the park. The proportion of older individuals was lower, and the calving interval was longer than estimates from Amboseli. We recognized 16% of elephants indexed in the previous study. Our results suggest that the individual identification technique may be useful in monitoring demographic changes including poaching in intermittently studied elephant populations. Overall, our results suggest that although the Meru elephant population showed signs of recovery, poaching continues to imperil its recovery.     

Perceptions and Patterns of Human–elephant Conflict in Old and New Settlements in Sri Lanka: Insights for Mitigation and Management

Human–elephant conflict poses a major threat to elephants in many parts of Asia, including Sri Lanka. We studied human–elephant conflict in two areas with contrasting scenarios of landuse and conflict, Kahalle and Yala. Kahalle was developed and settled under the Mahaweli irrigation project and the main agricultural practice was irrigated agriculture, with two annual growing seasons. The area was a mosaic of settlements, agriculture, and small forest patches with ill defined human- and elephant-use areas. Elephants ranged within the habitat mosaic year round, occupying remnant forest patches and raiding adjacent crops at night. In contrast, Yala was dominated by a large protected area complex, and the main agricultural methods were slash-and-burn agriculture and rain-fed paddy cultivation. Human- and elephant-use areas were well defined and segregated. The protected area provided elephants with a refuge and food during the rainy season, when the single annual crop was grown. During the dry season, elephants moved into slash-and-burn areas and utilized leftover crops and pioneer vegetation in fallow fields. The landuse pattern and agricultural practices in Yala facilitated co-existence, whereas that in Kahalle led to year round conflict. We suggest that areas managed according to traditional landuse practices should be part of an elephant conservation strategy, where people and elephants have to share resources.     

Temporal patterns of crop raiding by elephants: a response to changes in forage quality or crop availability?

Temporal patterns of crop raiding by elephants were studied for 13 months in 1996/1997 at Kibale Forest National Park, Uganda. To determine the influence of environmental factors on the timing of raiding, we tested for correlations between crop raiding patterns and the quality of natural forage within the forest as well as crop availability beyond park boundaries. Crop raiding occurred throughout the year with peaks in dry seasons when crop availability was high. Bananas and maize were the main crops raided. Variations in forage quality were moderate with small seasonal fluctuations and peaks in dry seasons. Monthly crop raiding incidences were not influenced by forage quality but by ripening of maize. Comparison of forage quality and temporal distribution of crop raiding between savanna and forest habitats suggests that crop availability is more important in forest habitats, whereas in savanna habitats large seasonal fluctuations in forage quality have a greater influence on temporal patterns of crop raiding.     

Perceived human–elephant conflict and its impact for elephant conservation in northern Congo

Human–elephant conflict is a common conservation problem throughout Africa, but poorly studied where forest elephants (Loxodonta cyclotis) occur. Here, we investigated people's perceptions towards the impact of elephants around Nouabalé‐Ndoki National Park, northern Congo. We aimed to understand the perceptual differences amongst residents of four villages that varied substantially in the degree of conservation benefits received. We used a multivariate analysis to investigate how socio‐economic variables, such as employment, wealth, education and ethnicity, influenced perceptions. Using both quantitative and qualitative data, we found that the majority of respondents experienced elephant impacts, mainly through crop raiding. Residents of the village where the local conservation project is based had significantly more positive perceptions of elephants, whereas perceptions of farmers were mostly negative. We identified some misunderstandings regarding the responsibilities of elephant impact mitigation regarding benefit sharing, stakeholder involvement and lawbreaking, but also willingness to apply mitigation measures. To mitigate the prevalent impact of elephants, a comprehensive approach of measuring impact, exploring community‐based mitigating strategies and understanding of the root causes of the conflict is crucial. We propose a long‐term programme within logging concessions organizing groups of farmers to cooperate on mitigation techniques and explore alternative incomes.     

Changes in Elephant Abundance Affect Forest Composition or Regeneration?

While overall numbers of African elephant have declined dramatically in recent times, some populations are now confined to protected areas and are locally overabundant—an undesirable situation for both biodiversity conservation and elephants. In forested protected areas, options to manage elephants are limited because it is difficult to safely approach animals, yet it is vital that these populations are managed because browsing by elephants can dramatically alter forest ecosystems. Using data collected over 50 yr in Kibale National Park, Uganda, we examine the prediction that increasing elephant numbers and associated changes in their foraging behavior have caused a shift in tree community composition. Although the relative abundance of elephants increased significantly between 1996 and 2010, the population structure of their preferred tree food species did not change, nor did tree community composition change in favor of species able to re‐sprout after elephant damage. Furthermore, over the last 50 yr Kibale elephants have not become more selective foragers, as would be expected if more nutritious tree species were declining. However, elephants are more abundant in disturbed areas dominated by shrubs and grasses and appear to have arrested forest succession in these areas. At their current abundance, elephants have not selectively altered the composition of intact old growth forest, but they do inhibit the regeneration of disturbed areas.     

The influence of life history milestones and association networks on crop-raiding behavior in male African elephants

Factors that influence learning and the spread of behavior in wild animal populations are important for understanding species responses to changing environments and for species conservation. In populations of wildlife species that come into conflict with humans by raiding cultivated crops, simple models of exposure of individual animals to crops do not entirely explain the prevalence of crop raiding behavior. We investigated the influence of life history milestones using age and association patterns on the probability of being a crop raider among wild free ranging male African elephants; we focused on males because female elephants are not known to raid crops in our study population. We examined several features of an elephant association network; network density, community structure and association based on age similarity since they are known to influence the spread of behaviors in a population. We found that older males were more likely to be raiders than younger males, that males were more likely to be raiders when their closest associates were also raiders, and that males were more likely to be raiders when their second closest associates were raiders older than them. The male association network had sparse associations, a tendency for individuals similar in age and raiding status to associate, and a strong community structure. However, raiders were randomly distributed between communities. These features of the elephant association network may limit the spread of raiding behavior and likely determine the prevalence of raiding behavior in elephant populations. Our results suggest that social learning has a major influence on the acquisition of raiding behavior in younger males whereas life history factors are important drivers of raiding behavior in older males. Further, both life-history and network patterns may influence the acquisition and spread of complex behaviors in animal populations and provide insight on managing human-wildlife conflict.     

Seasonal variation of feeding patterns and food selection by crop-raiding elephants in Zimbabwe

Elephants and humans are increasingly coming into conflict because of the conversion of elephant habitat into agricultural areas. In order to identify trends that influence raiding behaviour, the nutritional makeup of food items consumed by crop‐raiding elephants over a 2‐year period were analysed and a trigger for crop raiding was identified. The point at which the quality of wild grasses declines below the quality of crop species corresponded to the movement of bull elephants out of a protected area and into fields. This finding may have wider implications for developing predictive models of elephant/human interactions.     

Minimum population size,genetic diversity,and social structure of the Asian elephant in Cat Tien National Park and its adjoining areas,Vietnam, based on molecular genetic analyses

Vietnam’s elephant population that has suffered severe declines during the past three decades is now believed to number 60–80 individuals in the wild. Cat Tien National Park is thought to be one of the key areas for the recovery of Vietnam’s elephants. We carried out a molecular genetic study of elephants in Cat Tien National Park and its adjoining areas with the objectives of estimating minimum population size, assessing genetic diversity, and obtaining insights into social organization. We obtained a minimum population size of 11 elephants based on a combination of unique nuclear microsatellite genotypes and mitochondrial haplotypes. While mitochondrial diversity based on a 600-base pair segment was high in this small sample of individuals, the six microsatellite loci examined showed low diversity and the signature of a recent population bottleneck. Along with nuclear genetic depauperation of Cat Tien’s elephants, we also report disruption of normal social organization, with different matrilines having coalesced into a single social group because of anthropogenic disturbance. The results emphasize the critical condition of this elephant population and the need for urgent conservation measures if this population is to be saved.     

Heterogeneity in African savanna elephant distributions and their impacts on trees in Kruger National Park,South Africa

1. Though elephants are a major cause of savanna tree mortality and threaten vulnerable tree species, managing their impact remains difficult, in part because relatively little is known about how elephant impacts are distributed throughout space.
2. This is exacerbated by uncertainty about what determines the distribution of elephants themselves, as well as whether the distribution of elephants is even informative for understanding the distribution of their impacts.
3. To better understand the factors that underlie elephant impacts, we modeled elephant distributions and their damage to trees with respect to soil properties, water availability, and vegetation in Kruger National Park, South Africa, using structural equation modeling.
4. We found that bull elephants and mixed herds differed markedly in their distributions, with bull elephants concentrating in sparsely treed basaltic sites close to artificial waterholes and mixed herds aggregating around permanent rivers, particularly in areas with little grass.
5. Surprisingly, we also found that the distribution of elephant impacts, while highly heterogeneous, was largely unrelated to the distribution of elephants themselves, with damage concentrated instead in densely treed areas and particularly on basaltic soils.
6. Results underscore the importance of surface water for elephants but suggest that elephant water dependence operates together with other landscape factors, particularly vegetation community composition and historical management interventions, to influence elephant distributions.

     

Determining adrenocortical activity as a measure of stress in African elephants (Loxodonta africana) in relation to human activities in Serengeti ecosystem

African elephants (Loxodonta africana) play a vital role in most African ecosystems, with their opportunity to alter the entire ecosystem by their sheer numbers. Defining and measuring animal welfare has been much discussed. One potential way of determining an animal's welfare is to record the absence or presence of stress. Little research on elephant welfare has so far been performed in the Serengeti ecosystem. The aim of this study was to record the faecal glucocorticoid metabolite levels of African elephants in areas with high or with minimum human interference. A total of 117 faecal samples were collected from randomly located single elephants as well as family herds in the northern, central and western Serengeti National Park (SNP) as well as in Grumeti Game Reserve and Ikoma Open Area, northern Tanzania in 2010. Elephants had higher levels of faecal glucocorticoid metabolites in the areas outside, compared with areas inside SNP. No single males were observed outside SNP, and in general, higher abundance of elephants was observed inside SNP. This suggests that elephants may prefer to reside in the potential safer areas inside the national park, demonstrating the importance of protected areas to improve the welfare of elephants.     

The movement of African elephants in a human-dominated land-use mosaic

Land outside of gazetted protected areas is increasingly seen as important to the future of elephant persistence in Africa. However, other than inferential studies on crop raiding, very little is understood about how elephants Loxodonta africana use and are affected by human-occupied landscapes. This is largely a result of restrictions in technology, which made detailed assessments of elephant movement outside of protected areas challenging. Recent advances in radio telemetry have changed this, enabling researchers to establish over a 24-h period where tagged animals spend their time. We assessed the movement of 13 elephants outside of gazetted protected areas across a range of land-use types on the Laikipia plateau in north-central Kenya. The elephants monitored spent more time at night than during the day in areas under land use that presented a risk of mortality associated with human occupants. The opposite pattern was found on large-scale ranches where elephants were tolerated. Furthermore, speed of movement was found to be higher where elephants were at risk. These results demonstrate that elephants facultatively alter their behaviour to avoid risk in human-dominated landscapes. This helps them to maintain connectivity between habitat refugia in fragmented land-use mosaics, possibly alleviating some of the potential negative impacts of fragmentation. At the same time, however, it allows elephants to penetrate smallholder farmland to raid crops. The greater the amount of smallholder land within an elephant's range, the more it was utilized, with consequent implications for conflict. These findings underscore the importance of (1) land-use planning to maintain refugia; (2) incentives to prevent further habitat fragmentation; (3) the testing and application of conflict mitigation measures where fragmentation has already taken place.     

How do African elephants utilize the landscape during wet season? A habitat connectivity analysis for Sioma Ngwezi landscape in Zambia

1. The influence of environmental factors on the distribution and persistence of African elephants (Loxodonta africana) is pertinent to policy makers and managers to formulate balanced plans for different land‐use types.
2. The study focuses on movement of elephants and how they utilize foraging areas in Sioma Ngwezi landscape in Zambia by answering the following questions: (1) Which environmental variables and land‐cover class predict the movement of elephants during the wet season in Sioma Ngwezi landscape? (2) What is the wet season suitable habitat for elephants in Sioma Ngwezi landscape? (3) What are the major wet season movement corridors for elephants in Sioma Ngwezi landscape?
3. We used GPS telemetry data from the collared elephants to assess habitat connectivity. Maximum entropy (MaxEnt) and linkage mapper were the tools used to predict habitat suitability, movement corridors, and barriers in the landscape during the wet season.
4. The study identified elevation, land cover, and NDVI as the most important environmental predictors that modify the dispersal of elephants in the landscape during the wet season. Additionally, a total of 36 potential wet season corridors were identified connecting 15 core areas mainly used for foraging and protection from poachers in the landscape. Of these, 24 corridors were highly utilized and are suggested as priority corridors for elephant movement in the landscape.
5. The identified wet season habitats and functional corridors may help to combat elephant poaching by patrolling areas with high relative probability of elephant presence. The findings may also help abate human–elephant conflict such as crop‐raiding by managing identified corridors that run into agriculture zones in the game management area.

     

Physiological indicators of stress in African forest elephants (Loxodonta africana cyclotis) in relation to petroleum operations in Gabon,Central Africa

Aim Human activities are major determinants of forest elephant (Loxodonta africana cyclotis) distribution in Gabon, but the types and intensity of disturbance that elephants can tolerate are not known. We conducted dung surveys within the Gamba Complex of Protected Areas in SW Gabon to examine (1) the feasibility of noninvasive faecal analyses for monitoring stress physiology, and (2) the influence of petroleum operations on stress levels in forest elephants. Location Gabon, Central Africa. Methods We identified multiple dung piles from the same individual by matching their eight‐locus microsatellite genotypes, and measured faecal concentrations of glucocorticoid metabolites as an indicator of stress in areas subject to different levels of disturbance: (1) Loango National Park (2) an ‘industrial corridor’ dominated by oil fields, and (3) a nearby area of human settlements. Results We obtained unique microsatellite genotypes and faecal glucocorticoid metabolite (FGM) concentrations for 150 forest elephant individuals, which is the largest hormonal data set for wild African forest elephants to date. Adults exhibited higher mean FGM concentrations than juveniles, and in contradiction of our expectations of chronic stress around oil fields, elephants in Loango National Park exhibited significantly higher FGM concentrations than elephants in the industrial corridor. Main conclusions We argue that forest elephants in the industrial corridor of the Gamba Complex have become acclimated to oil fields, resulting in part from oil company regulations that minimize stressful interactions between elephants and petroleum operations. Our findings for a flagship species with substantial ecological requirements bode well for other taxa, but additional studies are needed to determine whether oil operations are compatible over their life span with rain forest ecosystems in Central Africa.     

Small-scale dung survey reveals high forest elephant density and preference for mixed species forest in an intact protected area

Understanding the ecological factors influencing African forest elephant (Loxodonta cyclotis) abundance and distribution is crucial for their conservation management in Central Africa. Dung surveys have been conducted at the landscape scale and confirmed the overwhelming impact of anthropogenic activities on forest elephants. We present results from a small-scale survey in a pristine protected area without anthropogenic activities to elucidate the ecological factors influencing forest elephant density. We conducted a line transect dung survey in a small study area (110 km²) around Mbeli Bai, a natural forest clearing in the Nouabalé-Ndoki National Park, Republic of Congo, and compare results with a landscape survey conducted during the same period. We used habitat specific dung decay data collected on site to estimate elephant density using distance sampling. We fitted Generalized Additive Models to elephant dung encounter rate using explanatory variables collected during the transect survey and from geospatial data. The small-scale survey revealed a precise estimate of forest elephant density that was twice as high as the result from a landscape survey with higher density in mixed species forest for the small-scale survey. We could not find an impact of the proximity of forest clearings and proximity to rivers at the small scale. Fine-scale habitat features, e.g. degree of canopy and understorey closure, had little explanatory power for elephant dung encounter rate. Small-scale dung surveys are a useful method to reveal spatio-temporal variation in forest elephant density and distribution which can inform conservation practitioners in a timely manner. Combining monitoring methods at various spatial scales improves our knowledge and conservation efforts of forest elephants. Nouabalé-Ndoki National Park is a stronghold for forest elephants and of global importance for their conservation.

     

A TECHNIQUE TO ‘TAG’ SPECIFIC VOCALIZATIONS IN TAPE-RECORDINGS OF COMPLEX VOCAL INTERACTIONS

ABSTRACT

It has been suggested that African savanna elephants Loxodonta africana produce 31 different call types (Langbauer 2000). Various researchers have described these calls by associating them with specific behavioural contexts. More recently Leong et al. (2003) have attempted to classify elephant call types based on their physical properties. They classified 8 acoustically distinct call types from a population of captive elephants. This study focuses on one of these call types, the rumble, in a wild population of elephants in Kruger National Park, South Africa. A single family group of elephants was followed to record group behaviours and vocalizations from January through August 2001. By measuring the physical properties of 663 rumbles and subjecting these to cluster analysis, we present evidence that shows that rumbles can be categorized by their physical properties and that the resulting rumble types are associated with specific group behaviours. We characterize three types of rumbles that differ significantly by ten acoustic parameters. Two rumble types were associated with the elephant group feeding and resting, while the third was associated with socializing and agitation.     

Elephant (Loxodonta africana) Home Ranges in Sabi Sand Reserve and Kruger National Park: A Five-Year Satellite Tracking Study

During a five-year GPS satellite tracking study in Sabi Sand Reserve (SSR) and Kruger National Park (KNP) we monitored the daily movements of an elephant cow (Loxodonta africana) from September 2003 to August 2008. The study animal was confirmed to be part of a group of seven elephants therefore her position is representative of the matriarchal group. We found that the study animal did not use habitat randomly and confirmed strong seasonal fidelity to its summer and winter five-year home ranges. The cow''s summer home range was in KNP in an area more than four times that of her SSR winter home range. She exhibited clear park habitation with up to three visits per year travelling via a well-defined northern or southern corridor. There was a positive correlation between the daily distance the elephant walked and minimum daily temperature and the elephant was significantly closer to rivers and artificial waterholes than would be expected if it were moving randomly in KNP and SSR. Transect lines established through the home ranges were surveyed to further understand the fine scale of the landscape and vegetation representative of the home ranges.     

Elephant (Loxodonta africana) Disturbance to Riparian Woodland: Effects on Tree-Species Richness,Diversity and Functional Redundancy

The substantial increase in elephant populations across many areas in southern Africa over past decades is prompting concerns about the effects on biodiversity. We investigated the outcomes of elephant disturbance on tree-species presence, density, and richness, and on alpha and beta diversity within riparian woodland in Chobe National Park, Botswana. We enumerated all tree species occurring in 32 plots (0.06 ha) along the Chobe riverfront. Plots were stratified by soil type (nutrient-rich alluvium vs. nutrient-poor Kalahari sand covering alluvium) and elephant impact (high vs. low impact on both soil types). We tested four predictions: elephants reduce tree density, richness, and alpha diversity; beta diversity is greater in vegetation subjected to high elephant impact; elephant impact on tree-species composition is greater on nutrient-poor than on nutrient-rich soil; and the loss or decline of abundant tree species on heavily disturbed sites is offset by an increase in abundance of functionally similar species, ones that are minor on lightly disturbed sites. Elephant browsing substantially affected tree-species composition, reducing density, species richness, evenness, and alpha diversity but had no effect on beta diversity. The dominant species on relatively undisturbed areas were partly replaced by functionally similar species on heavily disturbed sites. Soil type influenced species composition on lightly disturbed sites but was less important at higher elephant densities. Our findings are important for areas with extreme dry-season densities of elephants but should not be extrapolated to infer purported effects of elephants on tree diversity at lower densities.