Long-term studies of population dynamics can provide insights into life history theory, populatio... more Long-term studies of population dynamics can provide insights into life history theory, population ecology, socioecology, conservation biology and wildlife management. Here we examine 25 years of population dynamics of western gorillas at Mbeli Bai, a swampy forest clearing in Nouabalé-Ndoki National Park, the Republic of Congo. The Mbeli population more than doubled from 101 to 226 gorillas during the study. After adjusting for a net influx of gorillas into the study population, the increase represents an inherent growth rate of 0.7% per year, with 95% confidence limits between -0.7% and 2.6%. The influx of gorillas mainly involved immigration of individuals into existing study groups (social dispersal), but it also included the appearance of a few previously unknown groups (locational dispersal). The average group size did not change significantly during the study, which is consistent with the possibility that western gorillas face socioecological constraints on group size, even w...
Understanding what are the proximate mechanisms shaping species’ space-use dynamics, and at which... more Understanding what are the proximate mechanisms shaping species’ space-use dynamics, and at which scale, can provide insights into species socio-ecology. This is crucial information for both applied (e.g., conservation) and theoretical questions (e.g. individuals’ coexistence/segregation). Yet, longitudinal views of the space-use dynamics of animal species are generally lacking. Taking advantage of an unprecedented long-term data set (up to 8 years) on ranging patterns of wild western gorillas (Gorilla gorilla), we investigated the dynamics of home ranges in relation to socio-ecological variables in five habituated groups in Central Africa. First, we looked at the scale at which their ranging movements are stationary. Second, we studied how space use is shaped by (i) foraging and intra-group constraints (e.g., diet, group size, presence of offspring) by focusing on group daily path lengths, and by (ii) inter-group competition (direct or indirect), by quantifying static and dynamic i...
Biodiversity loss and climate change are two of the most significant environmental problems of th... more Biodiversity loss and climate change are two of the most significant environmental problems of the 21st century (Cardinale et al. 2012, IPCC 2014). Major initiatives to conserve biodiversity include international
Carnivores are threatened across Sub-Saharan Africa mostly due to retaliatory killing by people, ... more Carnivores are threatened across Sub-Saharan Africa mostly due to retaliatory killing by people, the loss of prey species and their habitats. Due to their food and space requirements, they regularly come into conflict with humans. In many regions, information about carnivore occurrence and human-carnivore conflict remains poorly known particularly in parts of West-and Central Africa. Here, we assessed the local ecological knowledge on carnivores and associated conflicts in the forest-savannah transition zone in Cameroon. We conducted a semi-structured questionnaire survey with 649 local inhabitants from 23 villages around the Tchabal Mbabo Mountain Range, Yoko Council Forest and Mpem et Djim National Park. The majority of local people could easily identify the lions (73.8%, n=479) and correctly named (90.2%, n=432), whereas other species (e.g. leopards, cheetahs,
ObjectivesSeveral theories have been proposed to explain the impact of ecological conditions on d... more ObjectivesSeveral theories have been proposed to explain the impact of ecological conditions on differences in life history variables within and between species. Here we compare female life history parameters of one western lowland gorilla population (Gorilla gorilla gorilla) and two mountain gorilla populations (Gorilla beringei beringei).Materials and MethodsWe compared the age of natal dispersal, age of first birth, interbirth interval, and birth rates using long‐term demographic datasets from Mbeli Bai (western gorillas), Bwindi Impenetrable National Park and the Virunga Massif (mountain gorillas).ResultsThe Mbeli western gorillas had the latest age at first birth, longest interbirth interval, and slowest surviving birth rate compared to the Virunga mountain gorillas. Bwindi mountain gorillas were intermediate in their life history patterns.DiscussionThese patterns are consistent with differences in feeding ecology across sites. However, it is not possible to determine the evolu...
Ecology, Conservation and Management of Wild Pigs and Peccaries
Asia and seven in African institutions for a global population of 458 individuals (Reiter 2013; s... more Asia and seven in African institutions for a global population of 458 individuals (Reiter 2013; see also Chapter 37 for more details; www.species360.org).
The earliest stone tool types, sharp flakes knapped from stone cores, are assumed to have played ... more The earliest stone tool types, sharp flakes knapped from stone cores, are assumed to have played a crucial role in human cognitive evolution. Flaked stone tools have been observed to be accidentally produced when wild monkeys use handheld stones as tools. Holding a stone core in hand and hitting it with another in the absence of flaking,free hand hitting,has been considered a requirement for producing sharp stone flakes by hitting stone on stone,free hand percussion. We report on five observations offree hand hittingbehavior in two wild western gorillas, using stone-like objects (pieces of termite mound). Gorillas are therefore the second non-human lineage primate showing free-hand hitting behavior in the wild, and ours is the first report for free hand hitting behavior in wild apes. This study helps to shed light on the morphofunctional and cognitive requirements for the emergence of stone tool production as it shows that a prerequisite for free hand percussion (namely, free hand h...
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Studies of the evolutionary relationships among gorilla populations using autosomal and mitochond... more Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male‐mediated gene flow may have been important in the past, but data on the Y‐chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y‐linked microsatellite loci resulting in 102 unique Y‐haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorill...
Primate populations are declining throughout tropical Africa. Great apes are threatened from exti... more Primate populations are declining throughout tropical Africa. Great apes are threatened from extinction despite the existence of wildlife laws that fully protect them in their range states. But, due to a lack of knowledge and understanding of these laws, they remain largely ineffective. There is, therefore, a crucial need to improve awareness of wildlife laws in Congo. We conducted an education campaign and tested the effectiveness of two communication tools (wildlife law flyer and gorilla/pet‐trade comic book) in increasing school children's knowledge in rural and urban settings using evaluation questionnaires. We found extremely low precampaign knowledge of wildlife laws but detected a moderate increase of knowledge attributed to our communication tools. We discuss the usefulness of different communication tools and their relevance for knowledge increase with different audiences. Our study provides insights into the design of education campaigns, most notably the use of flyers...
1. Department of Archaeology, University of Cambridge, Downing Street, Cambridge, CB2 3DZ 2. Mbel... more 1. Department of Archaeology, University of Cambridge, Downing Street, Cambridge, CB2 3DZ 2. Mbeli Bai Study, Wildlife Conservation Society Congo Program, B.P. 14537 Brazzaville, Republic of Congo 3. World Wide Fund for Nature, Reinhardtstrasse 18, 10117 Berlin, Germany 4. Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany 5. Apes Incorporated, 5301 Westbard Circle, Bethesda, MD 20816
Is it possible to slow the rate of aging, or do biological constraints limit its plasticity? We t... more Is it possible to slow the rate of aging, or do biological constraints limit its plasticity? We test this ‘invariant rate of aging’ hypothesis with an unprecedented collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of aging within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality. Finally, we demonstrate that changes in the rate of aging, but not other mortality parameters, produce striking, species-atypical changes in mortality patterns. Our results support the invariant rate of aging hypothesis, implying biological constraints on how much the human rate of aging can be slowed.
Ape social trait phylogenies Ape mating system properties show both a high degree of plasticity w... more Ape social trait phylogenies Ape mating system properties show both a high degree of plasticity within species and a high level of diversity between species. However, if we focus only on the size of alliances of males cooperating to control access to females (the number of socially bonded males within a single, reproductive, social group), the pattern becomes much less plastic and diverse. These male alliance sizes also relate more generally to the origins of higher level human cooperative networks, which tend not to hinge on the pattern of mating between males and females. Single male reproductive groups are the dominant theme in gibbons (Hylobatidae), orang-utans (Pongo), gorillas (Gorilla), and in human hunter gather societies, with less than 10% of reproductive units involving cooperation between more than one (most often two) male (1-5). Thus, we scored all of these taxa as predominantly single male. Communities in both species of the genus Pan are composed of alliances of multiple cooperating males (6,7), and these were therefore scored as multi-male. Ancestral state reconstruction shows broad support for single males defending a female (or females) at all internal nodes prior to the Pan genus (Fig. S4). In order for early hominins to have had multi-male groups, three evolutionary transitions are required: transitions from single to multi-male in the mountain gorilla sub-species and the Pan/Homo common ancestor, and a reversal back to single-male groups suggested to have taken place at roughly 1myBP (8). In contrast, if the Pan/Homo common ancestor is reconstructed as single male, only two transitions are required: single male to multi-male in both mountain gorillas and Pan. Social interaction Simple ratio association values were calculated for interactions that took place in the bai when individuals were ≤100m apart. Association values based on same day visits were highly consistent with association values based on interactions within 100m (Mantel test:
Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We ... more Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We test the ‘invariant rate of ageing’ hypothesis, which posits that the rate of ageing is relatively fixed within species, with a collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of ageing within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality. Finally, we demonstrate that changes in the rate of ageing, but not other mortality parameters, produce striking, species-atypical changes in mortality patterns. Our results support the invariant rate of ageing hypothesis, implying biological constraints on how much the human rate of ageing can be slowed.
Proceedings of the Royal Society B: Biological Sciences, 2019
Modern human societies show hierarchical social modularity (HSM) in which lower-order social unit... more Modern human societies show hierarchical social modularity (HSM) in which lower-order social units like nuclear families are nested inside increasingly larger units. It has been argued that this HSM evolved independently and after the chimpanzee–human split due to greater recognition of, and bonding between, dispersed kin. We used network modularity analysis and hierarchical clustering to quantify community structure within two western lowland gorilla populations. In both communities, we detected two hierarchically nested tiers of social structure which have not been previously quantified. Both tiers map closely to human social tiers. Genetic data from one population suggested that, as in humans, social unit membership was kin structured. The sizes of gorilla social units also showed the kind of consistent scaling ratio between social tiers observed in humans, baboons, toothed whales, and elephants. These results indicate that the hierarchical social organization observed in humans ...
This article may be used for non-commercial purposes in accordance With Wiley Terms and Condition... more This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving. Adamescu et al.
We present a range-wide assessment of sympatric western lowland gorillas and central chimpanzees ... more We present a range-wide assessment of sympatric western lowland gorillas and central chimpanzees using the largest survey data set ever assembled for these taxa: 59 sites in five countries surveyed between 2003 and 2013, totaling 61,000 person-days of fieldwork. We used spatial modeling to investigate major drivers of great ape distribution and population trends. We predicted density across each taxon's geographic range, allowing us to estimate overall abundance: 361,900 gorillas and 128,700 chimpanzees in Western Equatorial Africa-substantially higher than previous estimates. These two subspecies represent close to 99% of all gorillas and one-third of all chimpanzees. Annual population decline of gorillas was estimated at 2.7%, maintaining them as Critically Endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List. We quantified the threats to each taxon, of which the three greatest were poaching, disease, and habitat degradation. G...
Overexploitation is one of the main pressures driving wildlife closer to extinction, yet broad‐sc... more Overexploitation is one of the main pressures driving wildlife closer to extinction, yet broad‐scale data to evaluate species’ declines are limited. Using African pangolins (Family: Pholidota) as a case study, we demonstrate that collating local‐scale data can provide crucial information on regional trends in exploitation of threatened species to inform conservation actions and policy. We estimate that 0.4‐2.7 million pangolins are hunted annually in Central African forests. The number of pangolins hunted has increased by ∼150% and the proportion of pangolins of all vertebrates hunted increased from 0.04% to 1.83% over the past four decades. However, there were no trends in pangolins observed at markets, suggesting use of alternative supply chains. The price of giant (Smutsia gigantea) and arboreal (Phataginus sp.) pangolins in urban markets has increased 5.8 and 2.3 times respectively, mirroring trends in Asian pangolins. Efforts and resources are needed to increase law enforcement...
Human–elephant conflict is a common conservation problem throughout Africa, but poorly studied wh... more 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 eleph...
Long-term studies of population dynamics can provide insights into life history theory, populatio... more Long-term studies of population dynamics can provide insights into life history theory, population ecology, socioecology, conservation biology and wildlife management. Here we examine 25 years of population dynamics of western gorillas at Mbeli Bai, a swampy forest clearing in Nouabalé-Ndoki National Park, the Republic of Congo. The Mbeli population more than doubled from 101 to 226 gorillas during the study. After adjusting for a net influx of gorillas into the study population, the increase represents an inherent growth rate of 0.7% per year, with 95% confidence limits between -0.7% and 2.6%. The influx of gorillas mainly involved immigration of individuals into existing study groups (social dispersal), but it also included the appearance of a few previously unknown groups (locational dispersal). The average group size did not change significantly during the study, which is consistent with the possibility that western gorillas face socioecological constraints on group size, even w...
Understanding what are the proximate mechanisms shaping species’ space-use dynamics, and at which... more Understanding what are the proximate mechanisms shaping species’ space-use dynamics, and at which scale, can provide insights into species socio-ecology. This is crucial information for both applied (e.g., conservation) and theoretical questions (e.g. individuals’ coexistence/segregation). Yet, longitudinal views of the space-use dynamics of animal species are generally lacking. Taking advantage of an unprecedented long-term data set (up to 8 years) on ranging patterns of wild western gorillas (Gorilla gorilla), we investigated the dynamics of home ranges in relation to socio-ecological variables in five habituated groups in Central Africa. First, we looked at the scale at which their ranging movements are stationary. Second, we studied how space use is shaped by (i) foraging and intra-group constraints (e.g., diet, group size, presence of offspring) by focusing on group daily path lengths, and by (ii) inter-group competition (direct or indirect), by quantifying static and dynamic i...
Biodiversity loss and climate change are two of the most significant environmental problems of th... more Biodiversity loss and climate change are two of the most significant environmental problems of the 21st century (Cardinale et al. 2012, IPCC 2014). Major initiatives to conserve biodiversity include international
Carnivores are threatened across Sub-Saharan Africa mostly due to retaliatory killing by people, ... more Carnivores are threatened across Sub-Saharan Africa mostly due to retaliatory killing by people, the loss of prey species and their habitats. Due to their food and space requirements, they regularly come into conflict with humans. In many regions, information about carnivore occurrence and human-carnivore conflict remains poorly known particularly in parts of West-and Central Africa. Here, we assessed the local ecological knowledge on carnivores and associated conflicts in the forest-savannah transition zone in Cameroon. We conducted a semi-structured questionnaire survey with 649 local inhabitants from 23 villages around the Tchabal Mbabo Mountain Range, Yoko Council Forest and Mpem et Djim National Park. The majority of local people could easily identify the lions (73.8%, n=479) and correctly named (90.2%, n=432), whereas other species (e.g. leopards, cheetahs,
ObjectivesSeveral theories have been proposed to explain the impact of ecological conditions on d... more ObjectivesSeveral theories have been proposed to explain the impact of ecological conditions on differences in life history variables within and between species. Here we compare female life history parameters of one western lowland gorilla population (Gorilla gorilla gorilla) and two mountain gorilla populations (Gorilla beringei beringei).Materials and MethodsWe compared the age of natal dispersal, age of first birth, interbirth interval, and birth rates using long‐term demographic datasets from Mbeli Bai (western gorillas), Bwindi Impenetrable National Park and the Virunga Massif (mountain gorillas).ResultsThe Mbeli western gorillas had the latest age at first birth, longest interbirth interval, and slowest surviving birth rate compared to the Virunga mountain gorillas. Bwindi mountain gorillas were intermediate in their life history patterns.DiscussionThese patterns are consistent with differences in feeding ecology across sites. However, it is not possible to determine the evolu...
Ecology, Conservation and Management of Wild Pigs and Peccaries
Asia and seven in African institutions for a global population of 458 individuals (Reiter 2013; s... more Asia and seven in African institutions for a global population of 458 individuals (Reiter 2013; see also Chapter 37 for more details; www.species360.org).
The earliest stone tool types, sharp flakes knapped from stone cores, are assumed to have played ... more The earliest stone tool types, sharp flakes knapped from stone cores, are assumed to have played a crucial role in human cognitive evolution. Flaked stone tools have been observed to be accidentally produced when wild monkeys use handheld stones as tools. Holding a stone core in hand and hitting it with another in the absence of flaking,free hand hitting,has been considered a requirement for producing sharp stone flakes by hitting stone on stone,free hand percussion. We report on five observations offree hand hittingbehavior in two wild western gorillas, using stone-like objects (pieces of termite mound). Gorillas are therefore the second non-human lineage primate showing free-hand hitting behavior in the wild, and ours is the first report for free hand hitting behavior in wild apes. This study helps to shed light on the morphofunctional and cognitive requirements for the emergence of stone tool production as it shows that a prerequisite for free hand percussion (namely, free hand h...
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Studies of the evolutionary relationships among gorilla populations using autosomal and mitochond... more Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male‐mediated gene flow may have been important in the past, but data on the Y‐chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y‐linked microsatellite loci resulting in 102 unique Y‐haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorill...
Primate populations are declining throughout tropical Africa. Great apes are threatened from exti... more Primate populations are declining throughout tropical Africa. Great apes are threatened from extinction despite the existence of wildlife laws that fully protect them in their range states. But, due to a lack of knowledge and understanding of these laws, they remain largely ineffective. There is, therefore, a crucial need to improve awareness of wildlife laws in Congo. We conducted an education campaign and tested the effectiveness of two communication tools (wildlife law flyer and gorilla/pet‐trade comic book) in increasing school children's knowledge in rural and urban settings using evaluation questionnaires. We found extremely low precampaign knowledge of wildlife laws but detected a moderate increase of knowledge attributed to our communication tools. We discuss the usefulness of different communication tools and their relevance for knowledge increase with different audiences. Our study provides insights into the design of education campaigns, most notably the use of flyers...
1. Department of Archaeology, University of Cambridge, Downing Street, Cambridge, CB2 3DZ 2. Mbel... more 1. Department of Archaeology, University of Cambridge, Downing Street, Cambridge, CB2 3DZ 2. Mbeli Bai Study, Wildlife Conservation Society Congo Program, B.P. 14537 Brazzaville, Republic of Congo 3. World Wide Fund for Nature, Reinhardtstrasse 18, 10117 Berlin, Germany 4. Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany 5. Apes Incorporated, 5301 Westbard Circle, Bethesda, MD 20816
Is it possible to slow the rate of aging, or do biological constraints limit its plasticity? We t... more Is it possible to slow the rate of aging, or do biological constraints limit its plasticity? We test this ‘invariant rate of aging’ hypothesis with an unprecedented collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of aging within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality. Finally, we demonstrate that changes in the rate of aging, but not other mortality parameters, produce striking, species-atypical changes in mortality patterns. Our results support the invariant rate of aging hypothesis, implying biological constraints on how much the human rate of aging can be slowed.
Ape social trait phylogenies Ape mating system properties show both a high degree of plasticity w... more Ape social trait phylogenies Ape mating system properties show both a high degree of plasticity within species and a high level of diversity between species. However, if we focus only on the size of alliances of males cooperating to control access to females (the number of socially bonded males within a single, reproductive, social group), the pattern becomes much less plastic and diverse. These male alliance sizes also relate more generally to the origins of higher level human cooperative networks, which tend not to hinge on the pattern of mating between males and females. Single male reproductive groups are the dominant theme in gibbons (Hylobatidae), orang-utans (Pongo), gorillas (Gorilla), and in human hunter gather societies, with less than 10% of reproductive units involving cooperation between more than one (most often two) male (1-5). Thus, we scored all of these taxa as predominantly single male. Communities in both species of the genus Pan are composed of alliances of multiple cooperating males (6,7), and these were therefore scored as multi-male. Ancestral state reconstruction shows broad support for single males defending a female (or females) at all internal nodes prior to the Pan genus (Fig. S4). In order for early hominins to have had multi-male groups, three evolutionary transitions are required: transitions from single to multi-male in the mountain gorilla sub-species and the Pan/Homo common ancestor, and a reversal back to single-male groups suggested to have taken place at roughly 1myBP (8). In contrast, if the Pan/Homo common ancestor is reconstructed as single male, only two transitions are required: single male to multi-male in both mountain gorillas and Pan. Social interaction Simple ratio association values were calculated for interactions that took place in the bai when individuals were ≤100m apart. Association values based on same day visits were highly consistent with association values based on interactions within 100m (Mantel test:
Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We ... more Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We test the ‘invariant rate of ageing’ hypothesis, which posits that the rate of ageing is relatively fixed within species, with a collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of ageing within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality. Finally, we demonstrate that changes in the rate of ageing, but not other mortality parameters, produce striking, species-atypical changes in mortality patterns. Our results support the invariant rate of ageing hypothesis, implying biological constraints on how much the human rate of ageing can be slowed.
Proceedings of the Royal Society B: Biological Sciences, 2019
Modern human societies show hierarchical social modularity (HSM) in which lower-order social unit... more Modern human societies show hierarchical social modularity (HSM) in which lower-order social units like nuclear families are nested inside increasingly larger units. It has been argued that this HSM evolved independently and after the chimpanzee–human split due to greater recognition of, and bonding between, dispersed kin. We used network modularity analysis and hierarchical clustering to quantify community structure within two western lowland gorilla populations. In both communities, we detected two hierarchically nested tiers of social structure which have not been previously quantified. Both tiers map closely to human social tiers. Genetic data from one population suggested that, as in humans, social unit membership was kin structured. The sizes of gorilla social units also showed the kind of consistent scaling ratio between social tiers observed in humans, baboons, toothed whales, and elephants. These results indicate that the hierarchical social organization observed in humans ...
This article may be used for non-commercial purposes in accordance With Wiley Terms and Condition... more This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving. Adamescu et al.
We present a range-wide assessment of sympatric western lowland gorillas and central chimpanzees ... more We present a range-wide assessment of sympatric western lowland gorillas and central chimpanzees using the largest survey data set ever assembled for these taxa: 59 sites in five countries surveyed between 2003 and 2013, totaling 61,000 person-days of fieldwork. We used spatial modeling to investigate major drivers of great ape distribution and population trends. We predicted density across each taxon's geographic range, allowing us to estimate overall abundance: 361,900 gorillas and 128,700 chimpanzees in Western Equatorial Africa-substantially higher than previous estimates. These two subspecies represent close to 99% of all gorillas and one-third of all chimpanzees. Annual population decline of gorillas was estimated at 2.7%, maintaining them as Critically Endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List. We quantified the threats to each taxon, of which the three greatest were poaching, disease, and habitat degradation. G...
Overexploitation is one of the main pressures driving wildlife closer to extinction, yet broad‐sc... more Overexploitation is one of the main pressures driving wildlife closer to extinction, yet broad‐scale data to evaluate species’ declines are limited. Using African pangolins (Family: Pholidota) as a case study, we demonstrate that collating local‐scale data can provide crucial information on regional trends in exploitation of threatened species to inform conservation actions and policy. We estimate that 0.4‐2.7 million pangolins are hunted annually in Central African forests. The number of pangolins hunted has increased by ∼150% and the proportion of pangolins of all vertebrates hunted increased from 0.04% to 1.83% over the past four decades. However, there were no trends in pangolins observed at markets, suggesting use of alternative supply chains. The price of giant (Smutsia gigantea) and arboreal (Phataginus sp.) pangolins in urban markets has increased 5.8 and 2.3 times respectively, mirroring trends in Asian pangolins. Efforts and resources are needed to increase law enforcement...
Human–elephant conflict is a common conservation problem throughout Africa, but poorly studied wh... more 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 eleph...
Buffalo showed high site fidelity to open areas, including forest clearings. Forest buffalo herds... more Buffalo showed high site fidelity to open areas, including forest clearings. Forest buffalo herds (mean 12 ind. ± SD; range 3-24) were much smaller than records of savanna buffalo herds (mean 350 ind. ± SD; range 12-1500>), but also showed frequently fission-fusion patterns. Data from Mbeli Bai collected from 2006 to 2015 confirm a stable presence of two buffalo herds (range 7-9 ind.) with occasional visits by lone individuals. Observations from Dzanga Bai over a period of 23 years (1993-2016) confirm the occurrence of only one buffalo herd (range 1-27 ind.). In Bai-Hokou site, a single buffalo herd increased from 16 to 24 individuals during a three-year period (2001-2004). Finally in Lopé National Park (a mosaic of savanna and forest fragments), the mean group size for 18 herds monitored from 2002 to 2004 was 12±2 ind. (range of means 3–24). We analysed if herd size and herd stability are affected by clearing size, clearing type (e.g. marshy or sandy) and grass coverage across different sites and through time.
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