Forest Elephants Research Articles

African forest elephant social networks: fission-fusion dynamics, but fewer associations

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 25:165-173 (2014) - DOI: https://doi.org/10.3354/esr00618 African forest elephant social networks: fission-fusion dynamics, but fewer associations Stephanie G. Schuttler1,*, Alden Whittaker2, Kathryn J. Jeffery3,4,5, Lori S. Eggert1 1Division of Biological Sciences, 226 Tucker Hall, University of Missouri, Columbia, MO 65211, USA 2Zakouma National Park, African Parks Network, PO Box 510, N’Djaména, Republic of Chad 3Agence Nationale des Parcs Nationaux, BP20379, Libreville, Gabon 4School of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK 5Institut de Recherche en Ecologie Tropicale, BP13354, Libreville, Gabon *Corresponding author: stephanie.schuttler@gmail.com ABSTRACT: For animal species with dynamic interactions, understanding social patterns can be difficult. Social network analysis quantifies associations and their intensity between individuals within a population, revealing the overall patterns of the society. We used networks to test the hypothesis that the elusive African forest elephant Loxodonta cyclotis exhibits fission-fusion social dynamics, similar to other elephant species. We observed associations between individuals in savanna clearings in Lopé National Park, Gabon, in 2006, 2008, and 2010. When possible, dung was collected from individuals for genetic analyses using 10 microsatellite loci and the mitochondrial DNA control region. Using simple ratio association indices, networks were created for each year, wet and dry seasons, individuals detected at least twice, and for all females. We identified 118 unique adult females, for 40 of which we obtained genetic information. Networks had low densities, many disconnected components, short average path lengths, and high clustering coefficients. Within components, average relatedness was 0.093 ± 0.071 (SD) and females appeared to share mitochondrial haplotypes. We detected 1 large component consisting of 22 adult females, but there were few preferred associations (8 of 65, 12.3%). No seasonal or yearly differences were observed. Our results substantiate fission-fusion dynamics in forest elephants; however, the networks are more disconnected than those for other elephant species, possibly due to poaching and ecological constraints in the forest environment. KEY WORDS: Social networks · Social structure · Loxodonta cyclotis · Fission-fusion · Elephants Full text in pdf format Supplementary material PreviousNextCite this article as: Schuttler SG, Whittaker A, Jeffery KJ, Eggert LS (2014) African forest elephant social networks: fission-fusion dynamics, but fewer associations. Endang Species Res 25:165-173. https://doi.org/10.3354/esr00618 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 25, No. 2. Online publication date: September 19, 2014 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2014 Inter-Research.

Illegal killing for ivory drives global decline in African elephants.

Illegal wildlife trade has reached alarming levels globally, extirpating populations of commercially valuable species. As a driver of biodiversity loss, quantifying illegal harvest is essential for conservation and sociopolitical affairs but notoriously difficult. Here we combine field-based carcass monitoring with fine-scale demographic data from an intensively studied wild African elephant population in Samburu, Kenya, to partition mortality into natural and illegal causes. We then expand our analytical framework to model illegal killing rates and population trends of elephants at regional and continental scales using carcass data collected by a Convention on International Trade in Endangered Species program. At the intensively monitored site, illegal killing increased markedly after 2008 and was correlated strongly with the local black market ivory price and increased seizures of ivory destined for China. More broadly, results from application to continental data indicated illegal killing levels were unsustainable for the species between 2010 and 2012, peaking to ∼ 8% in 2011 which extrapolates to ∼ 40,000 elephants illegally killed and a probable species reduction of ∼ 3% that year. Preliminary data from 2013 indicate overharvesting continued. In contrast to the rest of Africa, our analysis corroborates that Central African forest elephants experienced decline throughout the last decade. These results provide the most comprehensive assessment of illegal ivory harvest to date and confirm that current ivory consumption is not sustainable. Further, our approach provides a powerful basis to determine cryptic mortality and gain understanding of the demography of at-risk species.

Foraging site recursion by forest elephants Elephas maximus borneensis

Abstract Recursion by herbivores is the repeated use of the same site or plants. Recursion by wild animals is rarely investigated but may be ubiquitous. Optimal foraging theory predicts site recursion as a function of the quality of the site, extent of its last use, and time since its last use because these influence site resource status and recovery. We used GPS collars, behaviour and site sampling to investigate recursion to foraging sites for two elephant Elephas maximus borneensis herds in the Lower Kinabatangan Wildlife Sanctuary, Borneo, over a 12 month period. Recursion occurred to 48 out of 87 foraging sites and was most common within 48 hours or between 151–250 days, indicating two different types of recursion. Recursion was more likely to occur if the site had previously been occupied for longer. Moreover, the time spent at a site at recursion was the same as the time spent at the site on the first occasion. The number of days that had passed between the first visit and recursion was also positively correlated with how much time was spent at the site at recursion. Habitat type also influenced the intensity of site-use, with more time spent at recursion within riverine/open grass areas along forest margins compared to other habitat types. Recursion is a common behaviour used by the elephants and its pattern suggests it may be a foraging strategy for revisiting areas of greater value. The qualities of recursion sites might usefully be incorporated into landscape management strategies for elephant conservation in the area [Current Zoology 60 (4): 551–559, 2014].

Using Cultural Resources in Host Communities and the Environs to Enhance the Natural Resources Attractiveness of Ecotourism Development in Omo Biosphere Reserve (OBR), Nigeria

The study was undertaken to evaluate the cultural resources in Omo Biosphere Reserve (OBR) host communities and its environs that can enhance the attractiveness of ecotourism development which can ultimately lead to the sustainable development of the area. OBR is in waterside area of Ogun State, Nigeria. It is a UNESCO designated Man and Biosphere (MAB) site. OBR natural resources has been under threat of overexploitation in the last few decades and hence the need to sustainably conserve and protect these resources using ecotourism. Fauna direct sighting particularly the large mammals like the forest elephants (Loxodonta africana cyclotis), forest buffalo (Syncerus caffer nanus) and others have been rare although their presence have been established. Interview and direct observation methods were used to collect primary data. Data collected were analysed and presented in tables. The result showed that there were significant festivals in OBR environs that can attract visitors to OBR. The study identified the incorporation of festivals in the OBR as added attractiveness for the natural resources in OBR in its ecotourism development. Development of ecotourism will not only conserve the endangered fauna and flora species of Omo Biosphere Reserve but will also provide additional income and job opportunities for the communities and will equally ensure peaceful co-existence of the people.

Low coverage sequencing of two Asian elephant (Elephas maximus) genomes.

BackgroundThere are three species of elephant that exist, the Asian elephant (Elephas maximus) and two species of African elephant (Loxodonta africana and Loxodonta cyclotis). The populations of all three species are dwindling, and are under threat due to factors, such as habitat destruction and ivory hunting. The species differ in many respects, including in their morphology and response to disease. The availability of elephant genome sequence data from all three elephant species will complement studies of behaviour, genetic diversity, evolution and disease resistance.FindingsWe present low-coverage Illumina sequence data from two Asian elephants, representing approximately 5X and 2.5X coverage respectively. Both raw and aligned data are available, using the African elephant (L. africana) genome as a reference.ConclusionsThe data presented here are an important addition to the available genetic and genomic information on Asian and African elephants.

Large-scale automatic acoustic monitoring of African forest elephants' calls in the terrestrial acoustic recordings

African forest elephants live in the rain forests of western and central Africa. The dense habitat prevents them from communicating visually within the family group. Automatic detection of African Forest Elephants' calls intercepts signals in their communication channel and enables fast processing of large scale acoustic data. In this work, first, an automatic detection system targeting at African forest elephants' rumble calls is proposed. De-noising pre-processing, design of acoustic feature vectors, and choice of classifiers are discussed respectively. Second, the detector's performance is evaluated by the cross-validation of a 432-h of acoustic recording from eight locations in Gabon, Africa. It shows that the detector achieve 79.19% true positive rate when the false positive number is the low 5.70 per hour. The F1-score (geometric mean of precision and recall) is around 0.77 when relatively high score threshold (over 0.8) is selected. Finally, a case study demonstrates the results of applying our automatic detection system to a large-scale data set, which amounts to 420 days of acoustic recording over 3 years from the Ivindo National Park, Gabon. Visualization of the call activities reveal the seasonal and daily patterns as well as the temporal variation over the 3 years.

An Assessment of the Takamanda-Mone Landscape as a Potential Forest Habitat for the African Forest Elephant (Loxodonta africana cyclotis) in the South West Region of Cameroon

The Humid Forest Zones (HFZ) of Central Africa, have relatively been understudied in the area of their potentials as large mammals habitats. This is particularly true for forest elephants which are predominantly migratory across large ecological landscapes. This migratory phenomenon makes it difficult to state with certainty their status and habitat need in time and space that can help conservationist and policy makers to designate /classify a landscape as a large mammal (elephant) habitat. It was from this backdrop of uncertainty that this study on the Assessment of the Takamanda-Mone landscape as a potential forest habitat for the African forest elephant (Loxodonta africana cyclotis) in the South West Region of Cameroon was consecrated. The study in order to achieve set objectives, made use of Socio-economic surveys that involved the use of questionnaire, some selected Participatory Rural Appraisal (PRA) tools. Biological assessment techniques such as transects, poacher guided survey as well as the use of the Geographic Information System (GIS), techniques were employed for data collection and analysis. Results revealed that the Takamanda-Mone landscape is a potential forest habitat for the African forest elephant (Loxodonta africana cyclotis). Their presence and migration in and out of the study area is known to be affected by the two seasons (dry and wet) that prevail in the areas. Their presence was found to be more marked in the wet and low in the dry season. Results further revealed that evidences of the African forest elephants (Loxodonta africana cyclotis) presence in the study area ranged from physical encounters and observation of the animals, left over of crops destroyed, recorded vocalisations of the animals far-off villages, forest fruits devastation, fresh and old forest tracks, footprints, feeding signs, debarking and felling of trees to dung droppings. The evidence of direct encounter and observing the animals was strongly associated with the older population (40 years and above). Result also showed that during some of the direct encounters with the population, the African forest elephants were known to have killed about 10 persons and injured about 17persons over the past 25 years in the study area. Conclusively, the study area is a habitat for the African Forest elephant (Loxodonta africana cyclotis) and is being recommended to be designated as a habitat for the protection of species and other wildlife species.

Fine-Scale Genetic Structure and Cryptic Associations Reveal Evidence of Kin-Based Sociality in the African Forest Elephant

Spatial patterns of relatedness within animal populations are important in the evolution of mating and social systems, and have the potential to reveal information on species that are difficult to observe in the wild. This study examines the fine-scale genetic structure and connectivity of groups within African forest elephants, Loxodonta cyclotis, which are often difficult to observe due to forest habitat. We tested the hypothesis that genetic similarity will decline with increasing geographic distance, as we expect kin to be in closer proximity, using spatial autocorrelation analyses and Tau Kr tests. Associations between individuals were investigated through a non-invasive genetic capture-recapture approach using network models, and were predicted to be more extensive than the small groups found in observational studies, similar to fission-fusion sociality found in African savanna (Loxodonta africana) and Asian (Elephas maximus) species. Dung samples were collected in Lopé National Park, Gabon in 2008 and 2010 and genotyped at 10 microsatellite loci, genetically sexed, and sequenced at the mitochondrial DNA control region. We conducted analyses on samples collected at three different temporal scales: a day, within six-day sampling sessions, and within each year. Spatial autocorrelation and Tau Kr tests revealed genetic structure, but results were weak and inconsistent between sampling sessions. Positive spatial autocorrelation was found in distance classes of 0–5 km, and was strongest for the single day session. Despite weak genetic structure, individuals within groups were significantly more related to each other than to individuals between groups. Social networks revealed some components to have large, extensive groups of up to 22 individuals, and most groups were composed of individuals of the same matriline. Although fine-scale population genetic structure was weak, forest elephants are typically found in groups consisting of kin and based on matrilines, with some individuals having more associates than observed from group sizes alone.

Unexpected palaeoecological features of the Middle and Late Pleistocene large herbivores in southwestern Germany revealed by stable isotopic abundances in tooth enamel

Species flexibility in diet and habitat and their ability to tolerate a range of unfavourable ecological conditions and survive in unusual habitats accompanied by unexpected faunal components has been determined from various research fields. We present the dietary and environmental reconstructions of interglacial and glacial large mammals from central Germany (Bockstein and Vogelherd caves, Steinheim and Mauer) during the Middle and Late Pleistocene, using carbon and oxygen stable isotope relative abundances in the carbonate fraction of tooth enamel. The same species existed in central Europe during different temperature and ecosystem regimes. It appeared that the species during the glacial periods demonstrated much narrower ranges δ13C and δ18O than during the interglacial periods and at the dawn of the species origination. Intriguingly, the early woolly mammoth Mammuthus primigenius fraasi apparently lived in much milder conditions than the late woolly mammoth Mammuthus primigenius primigenius, and shared similar diet and habitat with the straight-tusked forest elephant Palaeoloxodon antiquus. Bovids existed in extremely open habitat at Steinheim, probably during the Saalian glacial, compared to other glacial species. Woolly rhinoceros Coelodonta antiquitatis and the early woolly mammoth came to occupy similar environments only later, during the Weichselian glacial period in Bockstein and Vogelherd caves. A so-called “steppe rhinoceros” Stephanorhinus hemitoechus occurred in the forested habitat, along with the Merck's rhino Stephanorhinus kirchbergensis. The horses appear to have preferred warmer and denser habitat than the woolly rhinoceros during the Pleistocene. The Pleistocene donkeys shared the ecological niches between bovids and horses. These new results demonstrate that stable isotope analyses can be extremely helpful to determine more detailed paleodiet and paleohabitat of extinct species. It appears that the deviation of the inferred palaeoecological patterns from the patterns deduced from modern survivors' ecology increases with increasing age, and species appeared more flexible at their origin.

Carthage and the Indian Elephant

Several scholars have asserted that Carthage deployed at least one Indian elephant in the Punic Wars, even though it is generally recognized that African forest elephants constituted the mainstay of the Carthaginian elephant corps. This article looks at the literary, numismatic and contextual evidence for Indian elephants in Carthaginian service, together with the various arguments advanced by a variety of scholars to support this view. Overall, it appears to be highly unlikely that Indian elephants were deployed in Punic service, with their provenance being particularly problematic given Carthage’s relationship with potential suppliers.

Long-Term Monitoring of Dzanga Bai Forest Elephants: Forest Clearing Use Patterns

Individual identification of the relatively cryptic forest elephant (Loxodonta cyclotis) at forest clearings currently provides the highest quality monitoring data on this ecologically important but increasingly threatened species. Here we present baseline data from the first 20 years of an individually based study of this species, conducted at the Dzanga Clearing, Central African Republic. A total of 3,128 elephants were identified over the 20-year study (1,244 adults; 675 females, 569 males). It took approximately four years for the majority of elephants visiting the clearing to be identified, but new elephants entered the clearing every year of the study. The study population was relatively stable, varying from 1,668 to 1,864 individuals (including juveniles and infants), with increasingly fewer males than females over time. The age-class distribution for females remained qualitatively unchanged between 1995 and 2010, while the proportion of adult males decreased from 20% to 10%, likely reflecting increased mortality. Visitation patterns by individuals were highly variable, with some elephants visiting monthly while others were ephemeral users with visits separated by multiple years. The number of individuals in the clearing at any time varied between 40 and 100 individuals, and there was little evidence of a seasonal pattern in this variation. The number of elephants entering the clearing together (defined here as a social group) averaged 1.49 (range 1–12) for males and 2.67 (range 1–14) for females. This collation of 20 years of intensive forest elephant monitoring provides the first detailed, long term look at the ecology of bai visitation for this species, offering insight to the ecological significance and motivation for bai use, social behavior, and threats to forest elephants. We discuss likely drivers (rainfall, compression, illegal killing, etc.) influencing bai visitation rates. This study provides the baseline for future demographic and behavioral studies of this population.

The most interesting finds of Late Pleistocene megafauna, Vologda Region (Russia)

The paleontological collections of museums of northern European Russia include unpredictable finds, such as the tooth of the forest elephant Elephas (Palaeoloxodon) antiquus (Falconer) in the collection of the Cherepovets Museum of Nature. The aim of the research is to define more precisely its systematic reference, age, and individual characteristics. The find indicates that the forest zone extended to 59–60°N during the Mikulin (Eemian) interglacial.The paleontological collections of Vologda regional museums include exhibits referred to the Late Pleistocene, namely Mammuthus primigenius, Equus sp., Rangifer tarandus, Bison priscus, and Ovibos pallantis. The majority of the finds conform to the transitional periods of warm and cold spells of the middle Valdai. Some Holocene finds of the region indicate the existence of favorable conditions for large-mammal species to inhabit the areas near 60°N.

Differentiation in mineral constituents in elephant selected versus unselected water and soil resources at Central African bais (forest clearings)

Natural forest clearings (bais) in the Central African rain forest attract large numbers of mammals. Little is known about the factors influencing bai use by forest species, though geophagy and hydro-mineral resources are assumed to be im- portant attractants. In the present study, clay and mineral con- centrations in water and soil were examined at 15 bais. Water samples from elephant excavated pits showed significantly higher concentrations of most minerals sampled relative to surface waters. But mineral portfolios varied markedly between bais. Geophagy sites were less differentiated from control soil samples, leading to the interpretation that geophagy may not structure bai visitation. Monthly samplingof pit water atone bai suggested higherdry season mineralconcentrations, which may relate to seasonal wildlife visitation patterns. The complexity and variability in bai-specific mineral resources suggest there is not a single determining factor (or mineral) driving bai use. The protection of bai mosaics should be a conservation priority in order to ensure access to the portfolio of minerals likely re- quired by endangered species such as the African forest ele- phant Loxodonta africana cyclotis.

Using Genetic Profiles of African Forest Elephants to Infer Population Structure, Movements, and Habitat Use in a Conservation and Development Landscape in Gabon

Conservation of wide-ranging species, such as the African forest elephant (Loxodonta cyclotis), depends on fully protected areas and multiple-use areas (MUA) that provide habitat connectivity. In the Gamba Complex of Protected Areas in Gabon, which includes 2 national parks separated by a MUA containing energy and forestry concessions, we studied forest elephants to evaluate the importance of the MUA to wide-ranging species. We extracted DNA from elephant dung samples and used genetic information to identify over 500 individuals in the MUA and the parks. We then examined patterns of nuclear microsatellites and mitochondrial control-region sequences to infer population structure, movement patterns, and habitat use by age and sex. Population structure was weak but significant, and differentiation was more pronounced during the wet season. Within the MUA, males were more strongly associated with open habitats, such as wetlands and savannas, than females during the dry season. Many of the movements detected within and between seasons involved the wetlands and bordering lagoons. Our results suggest that the MUA provides year-round habitat for some elephants and additional habitat for others whose primary range is in the parks. With the continuing loss of roadless wilderness areas in Central Africa, well-managed MUAs will likely be important to the conservation of wide-ranging species.

Response to ‘How far did dinosaurs really migrate, and how hot do elephants really get?’

The results of our study ([Rowe et al., 2013][1]) demonstrated a functionally significant relationship between heat storage and submaximal exercise in Asian elephants ( Elephas maximus ), which was sensitive to seasonal variations in radiant environmental heat. In addition, we modeled behavioral

How far did dinosaurs really migrate, and how hot do elephants really get?

Some points presented in the paper by Rowe et al. (Rowe et al., 2013) require discussion.Rowe and colleagues presume that multitonne Late Cretaceous high latitude hadrosaurs migrated thousands of straightline kilometers each year to avoid severe arctic winter conditions. However, movements over such extreme distances are limited to marine and aerial creatures in the contemporary world, with many traveling many degrees of latitude to experience warm weather year round. This is practical for fliers and especially swimmers because their transport costs per unit distance traveled are modest. In contrast the longest ranged living land migrators, such as gnu and even caribou, do not move a straightline distance of more than a few hundred kilometers (Fancy et al., 1989), seasonal movements are always subregional efforts to find optimal conditions at a given time and place in the general area, and no modern land walker migrates north–south far enough to evade winter climates. This is probably because animal land locomotion is so energy inefficient that continent-spanning movements are too arduous and cost too much to be worth any gain, are excessively dangerous, would involve problems with feeding, and are hindered by geographic obstacles (Paul, 1988; Paul, 1994; Paul, 2012).Specific to arctic hadrosaurs, most of the high latitude remains are those of juveniles too small to keep up with adults on long trips (Fiorillo, 2004). The taphonomic evidence indicates that most of the fossils were formed as the result of late winter/early spring riverine floods from mountain snowmelts (Fiorillo et al., 2010). If so, then the herds were already near or on the Alaskan North Slope as the winter ended, and lacked the time to have moved up far from the south. This is verified by Alaskan hadrosaur bone histology showing they were perennial residents that tolerated the winters, and were a distinct population from more southerly hadrosaurs whose bone microstructure is markedly different (Chinsamy et al., 2012). It is therefore well established that polar hadrosaurs were year-round residents (Paul, 1998; Paul, 1994; Paul, 2012; Fiorillo, 2004; Fiorillo et al., 2010; Chinsamy et al., 2012). It is similarly known that some giant polar southern hemisphere dinosaurs had to tolerate winter and cold and dark because there was no land to the north to migrate on (Bell and Snively, 2008; Paul, 2012). The possibility that polar hadrosaurs, or any other land animals, migrated thousands of kilometers must be ranked as very low and probably impossible, so such fictional creatures should no longer be modeled as plausible unless supporting fossil evidence is produced.Presuming the polar hadrosaurs were permanent residents, then they rarely or never experienced warm conditions even in the summers, which were cool and cloudy (Spicer and Herman, 2010). However, giant hadrosaurs lived at all latitudes during a global warm period, so modeling their thermoregulation under high heat loads is valid. Rowe and colleagues (Rowe et al., 2013) logically used the largest, low latitude land animals available, elephants, to help understand the thermal performance of similar-sized and probably tachyenergetic dinosaurs that experienced high ambient temperatures. What is not clear is whether the captive Elephas maximus they utilized experienced the extreme heat loads that may be tolerated by Loxodonta africana living in their most hyperthermally acute habitats. Elephant herds of the coastal Namib Desert have been documented crossing expansive, shade-barren flats in daytime when air temperatures were probably above their body temperatures; their daily range can exceed 100 km and they can go without water for days (Viljoen, 1992; Bartlett and Bartlett, 1992) (D. Bartlett, personal communication). It is possible that these elephants of the arid Skeleton Coast are adapted to remain active under higher daytime heat loads than data on captive forest elephants and modeling may suggest is feasible. But they have never been sufficiently studied to determine exactly what they experience, and how they cope with intense heat. To fully understand the thermoregulation of gigantic, tachyenergetic animals will require detailed field observation of the biggest living land animals residing in the hottest habitats to discover how they do it. That, of course, will be a difficult and expensive experiment to conduct.

People and wildlife: Conflicts arising around the Bia Conservation Area in Ghana

Human–wildlife conflicts have drastically increased around conservation areas in Africa over the last decades. Underlying causes are similar across regions and can most often be attributed to land-use changes and increasing human populations. However, wildlife species composition involved in conflicts can vary tremendously across sites. Conflict assessment often focuses on prominent species such as elephants or other large mammals, and information on smaller wildlife species involved in conflicts is often lacking. We conducted 100 interviews in 10 communities around the Bia Conservation Area (BCA), Ghana, to address the type and extent of damage as well as possible factors influencing the risk of crop-raids. We assessed wildlife presence and relative densities through indirect observations on transects and spoor-plots in the transition zone between BCA and agricultural land. Crop-raiding was present across all communities interviewed but was more than twice as high in the north compared to the south. Squirrels (Sciuridae spp.) were the most frequent crop-raiding species (92% of farmers experienced damage), but elephants (Loxodonta africana cyclotis [Matschie, 1900]) were nevertheless the major conflict generating species (84% of farmers experienced damage). Squirrel signs were 75 times as frequent as any other species recorded in the farmland. Cocoa (Theobroma cacao) was most frequently raided (99%), followed by cassava (Manihot esculenta) and yam (Dioscorea spp.). Raiding might have been promoted through inappropriate agricultural practices while only few current mitigation strategies have been successful so far. Promising strategies include chili fences and buffer zones, in which less susceptible crops such as chili pepper are planted. Further education of farmers on mitigation measures is needed, including training on improved farming practices.

Effective sociodemographic population assessment of elusive species in ecology and conservation management.

Wildlife managers are urgently searching for improved sociodemographic population assessment methods to evaluate the effectiveness of implemented conservation activities. These need to be inexpensive, appropriate for a wide spectrum of species and straightforward to apply by local staff members with minimal training. Furthermore, conservation management would benefit from single approaches which cover many aspects of population assessment beyond only density estimates, to include for instance social and demographic structure, movement patterns, or species interactions. Remote camera traps have traditionally been used to measure species richness. Currently, there is a rapid move toward using remote camera trapping in density estimation, community ecology, and conservation management. Here, we demonstrate such comprehensive population assessment by linking remote video trapping, spatially explicit capture–recapture (SECR) techniques, and other methods. We apply it to three species: chimpanzees Pan troglodytes troglodytes, gorillas Gorilla gorilla gorilla, and forest elephants Loxodonta cyclotis in Loango National Park, Gabon. All three species exhibited considerable heterogeneity in capture probability at the sex or group level and density was estimated at 1.72, 1.2, and 1.37 individuals per km2 and male to female sex ratios were 1:2.1, 1:3.2, and 1:2 for chimpanzees, gorillas, and elephants, respectively. Association patterns revealed four, eight, and 18 independent social groups of chimpanzees, gorillas, and elephants, respectively: key information for both conservation management and studies on the species' ecology. Additionally, there was evidence of resident and nonresident elephants within the study area and intersexual variation in home range size among elephants but not chimpanzees. Our study highlights the potential of combining camera trapping and SECR methods in conducting detailed population assessments that go far beyond documenting species diversity patterns or estimating single species population size. Our study design is widely applicable to other species and spatial scales, and moderately trained staff members can collect and process the required data. Furthermore, assessments using the same method can be extended to include several other ecological, behavioral, and demographic aspects: fission and fusion dynamics and intergroup transfers, birth and mortality rates, species interactions, and ranging patterns.

Modeling harvest rates and numbers from age and sex ratios: A demonstration for elephant populations

Illegal harvest rates of wildlife populations are often unknown or difficult to estimate from field data due to under-reporting or incomplete detection of carcasses. This is especially true for elephants that are killed for ivory or in conflicts with people. We describe a method to infer harvest rates from coarse field data of three population parameters, namely, adult female to male ratio, male old-adult to young-adult ratio, and proportion of adult males in the population using Jensen’s (2000) 2-sex, density-dependent Leslie matrix model. The specific combination of male and female harvest rates and numbers can be determined from the history of harvest and estimate of population size. We applied this technique to two populations of elephants for which data on age structure and records of mortality were available—a forest-dwelling population of the Asian elephant (at Nagarahole, India) and an African savannah elephant population (at Samburu, Kenya) that had experienced male-biased harvest regimes over 2–3decades. For the Nagarahole population, the recorded numbers of male and female elephants killed illegally during 1981–2000 were 64% and 88% of the values predicted by the model, respectively, implying some non-detection or incomplete reporting while for the Samburu population the recorded and modeled numbers of harvest during 1990–1999 closely matched. This technique, applicable to any animal population following logistic growth model, can be especially useful for inferring illegal harvest numbers of forest elephants in Africa and Asia.

Assessing species occurrence and species‐specific use patterns of bais (forest clearings) in Central Africa with camera traps

AbstractThe impacts of increasing resource extraction on biodiversity in the Central African rainforest are largely unknown, in part due to the lack of baseline data on species occurrence across the basin. Natural forest clearings (bais) in this region are key habitats for a variety of vertebrates and offer opportunities for monitoring species distribution. Information on species composition, however, is lacking from the majority of areas (except for long‐term study sites). Approaches and protocols for short‐term bai assessments can greatly advance such baseline knowledge. This study demonstrates that camera traps provide an effective method for species inventories (species occurrence and temporal activity patterns) and monitoring at bais across the broader region. In comparison with direct observational studies, they performed especially well regarding rare and nocturnal species. Camera traps during sampling sessions of 4 weeks or less recorded previously undocumented, and 65–94% of the mammals known to use each of seven Central African bais. Results indicate that many mammal species, in particular African forest elephants (Loxodonta africana cyclotis), visit bais preferentially at night. This underlines the urgent need for monitoring tools providing both diurnal and nocturnal data to provide baseline data that address conservation and management objectives.