Differential response of seven duiker species to human activities in Taï National Park,Côte d'Ivoire

African rainforest is severely impacted by human activities, ranging from resource collection, selective logging to fragmentation and scale deforestation. Consequently, large mammal communities occurring therein are strongly modified. Here, we present a study conducted in Taï National Park (TNP), which characterises the spatial distribution and differential response of seven duiker species to human activities. Based on extensive survey data recorded between 2005 and 2015, we used a maximum entropy modelling approach for predicting duiker species distribution and a hierarchical clustering approach to identify potential subgroups in the duiker community. The seven duiker species clearly differed in their spatial distribution, with Cephalophus dorsalis and Philantomba maxwellii being the most common and widely distributed with no clear response towards gradients of impact from human activities. In contrast, Cephalophus ogilbyi, Cephalophus jentinki, Cephalophus sylvicultor and Cephalophus zebra showed increasing responses towards anthropogenic impact gradients, with the latter two being particularly sensitive. These duikers are not found in areas of illegal human activities. The restricted distribution of Cephalophus niger seems artificial and may indicate species misidentification. The strong spatial signature of human activities in the duiker community of TNP is of concern. Effective park management, including extensive ranger patrols, is vital for ensuring the persistence of this unique duiker community in West Africa.     

Bushmeat Consumption and Preferences of Two Ethnic Groups in Bioko Island, West Africa

We studied consumption and preference of meats of wild species (bushmeat) by inhabitants of Bioko Island, Equatorial Guinea. The aim of the study was to quantify frequency of consumption and stated preferences of the two main ethnic groups (Bubi and Fang) in the island. Although members of both ethnic groups lived on the island, the Fang originated from the continent and maintained strong links with this area. Thus, preference and consumption of the Fang reflected exposure to animals found in the continent as well as on Bioko. A sample of 196 subjects (115 Bubi and 81 Fang) was interviewed using semistructured questionnaires. A total of 55 different bushmeat species was identified as preferred or consumed by interviewees. Principal component analyses of stated consumption and preference indicated differences between ethnic groups in their general responses. Further analyses of the effects of preference and other factors on consumption of the three main species mentioned (blue duiker (Cephalophus monticola), Emin's rat (Cricetomys emini), and brush-tailed porcupine (Atherurus africanus) were undertaken. Proportional odds logistic regression models for ordered categorical response data were employed. Results indicated that age and sex of the respondent did not affect consumption, but ethnic group was statistically significant for the three-study species. Consumption and preference of the different meats (N = 11 species) in relation to their availability in the market and price was studied using multiple linear regressions. Consumption is driven predominantly by availability but there is some influence of preference; price of the meat did not have a significant influence.     

Chimpanzees and their mammalian sympatriates in the Issa Valley,Tanzania

Chimpanzees have been studied for nearly 300 combined years across Africa, but aside from their roles as predators or prey, remarkably little is known about the diverse species with whom they share habitats. We calculated likely chimpanzee encounter rates with sympatric mammals in the Issa Valley, Tanzania, through modelling actual researcher encounter rates with all medium and large mammals. Compared to other long‐term chimpanzee study sites, Issa had a relatively high diversity in medium and large mammal species present, with 36 species documented. We encountered common duiker (Sylvicapra grimmia) most frequently, followed by yellow baboons (Papio cynocephalus) and bushbuck. Chimpanzees ranked fifth overall. Chimpanzees, on the other hand, were predicted to most frequently encounter bushbuck, klipspringer and hartebeest—all woodland species. We compare these results to published literature and contextualise them in light of reconstructing diverse mammalian communities in which hominins lived during the Plio‐Pleistocene and the use of chimpanzees as flagship species for conservation policy.     

Intrasite variation in the ability to detect tropical forest mammals

Monitoring programs are essential for an adequate management of large mammal populations. Within Central Africa data on abundance of important bushmeat species, such as duikers and primates are often lacking. Relative densities [(encounter rates (ERs)] are often the only available data, but there is little knowledge on the factors affecting ERs and detection of these animals. Here we investigate how different environmental factors and observers influence large mammal ERs in a pristine rainforest in the Nouabalé‐Ndoki National Park, Republic of Congo. Our results show large daily and monthly variation in ERs of duikers and primates. ERs varied between habitat types, seasons and observers′ ability to detect animals. Season and rainfall had a strong effect on understory visibility and duiker detection, respectively. Detection of duikers often happened by sound instead of visual observations. Our study shows that the use of ER is a poor monitoring approach and more robust methods need to be used to evaluate rates of population change reliably.     

Pattern and sustainability of the bushmeat trade in the Haut Niger National Park,Republic of Guinea

To document the bushmeat trade in the buffer zone of the Haut Niger National Park (HNNP), Republic of Guinea, we monitored the number of carcasses offered for sale in 16 villages over a one year period in 2001. Overall, we counted a total of 9134 carcasses from 27 species. This represents a biomass harvest of about 170,000 kg, a figure that could reach 335,100 kg when game consumed by hunters (i.e. not sold) and markets not sampled are taken into account. Ungulates (eleven species) and rodents (four species) accounted for 53.5% and 24.8% of the carcasses counted respectively (80.8% and 11.4% of the total biomass, respectively). The number of carcasses counted in villages bordering a heavily trafficked road was significantly higher than in more rural villages, thus highlighting the stimulating effect of roads on the bushmeat trade. Compared with existing data collected in 1995, the proportion of ungulates counted in the Mansira Moribaya village in 2001 increased significantly while that of rodents decreased significantly. The harvest of duiker species at Mansira Moribaya was in excess of the maximum sustainable harvest. These results of this study were used to establish a sustainable wildlife management scheme in the HNNP.     

Identifying Conservation Opportunities among Malinké Bushmeat Hunters of Guinea,West Africa

Bushmeat hunting plays an important role in many rural African households; however, hunting pressures are growing, threatening the survival of many bushmeat species. Wildlife resources are rapidly dwindling; yet effective conservation strategies have been difficult to develop and implement. Many dimensions of bushmeat resource use have not been sufficiently explored and are consequently ignored in conservation interventions. To improve understanding of hunting practice, we conducted semistructured interviews with 74 hunters in three Malinké villages in Guinea, West Africa regarding motivations to hunt and hunting processes. In addition, we investigated the local bushmeat trade in a nearby city. Using data from previous studies, and Robinson and Redford’s (1991) model, we find that Red-flanked duiker, bushbuck and buffalo are unsustainably harvested. Malinké hunters’ perspectives offer both opportunities and obstacles for conservation which will be valuable for the development of conservation strategies in this area.     

Chimpanzee predation in the Mahale mountains from August 1979 to May 1982

Fifty-four episodes of predatory behavior of wild chimpanzees were recorded in Mahale, western Tanzania, from August 1979 to May 1982. The chimpanzees most frequently hunt in two seasons, during May, and from August to December. Longer-term fecal analysis indicates that predation frequency is significantly higher in the dry than in the rainy season. The seasonality of predation might be the result of the sum of various ecological factors, at least one of which is the birth season of the prey species. Most of the prey are juvenile blue duiker, bushbuck, bushpig, red colobus, and red-tailed monkeys. Sex difference is recognized in the prey selection and in the hunting method employed. Apparent local difference in the predatory behavior between Mahale and Combe chimpanzees (in Mahale,females hunt more frequently, and blue duiker is the most frequent prey) can be understood in terms of the difference either in the observation methods or in the faunal diversity and density. Other aspects of predatory behavior also are reported.     

A camera trap assessment of terrestrial vertebrates in Bwindi Impenetrable National Park,Uganda

We placed camera traps for a month at sixty locations in Bwindi Impenetrable National Park to determine the species composition and distribution of medium‐to‐large terrestrial vertebrates. A total of 15912 images were recorded from 1800 camera trap days. These provided a total of 625 and 338 camera events when filtered by hour and day, respectively. Twenty mammal species were recorded from 594 and 314 camera events by hour and day, respectively. Four bird species were recorded from 31 and 24 camera events by hour and day, respectively. The African golden cat Profelis aurata Temminck was recorded from 27 and nineteen camera events by hour and day, respectively. The black‐fronted duiker Cephalophus nigrifrons Gray was most frequently photographed with 179 and 65 camera events by hour and day, respectively. Analyses reveal two species possessed a significantly interior‐biased distribution. One species showed an edge‐biased pattern. Five species were detected to have significantly biased altitudinal distributions with higher elevations. Distance to park edge and elevation can significantly influence species distribution. The selective use of the park limits the area that each species utilizes, with implications for maximum population sizes and viability. Our observations provide a baseline for long‐term terrestrial vertebrate monitoring in Bwindi.     

Small ruminants: Digestive capacity differences among four species weighing less than 20 kg

Small ruminants are generally classified as either browsers or frugivores. We compared intake and digestion in one browsing species, the pudu (Pudu pudu), body weight 9 kg, and three frugivorous species, the red brocket (Mazama americana), 20 kg, the bay duiker (Cephalophus dorsalis), 12 kg, and Maxwell's duiker (C. maxwellii), 9 kg. Rations comprised: a commercial grain and alfalfa pellet, a small amount of vegetables, and mixed hay. Across species, neutral-detergent fiber (insoluble fiber) consumed averaged 34.2 ± 2.6% of dry matter (DM) while the crude protein consumed averaged 16.1 ± 0.5% DM. Apparent DM digestion was similar in pudu (75.2 ± 4.7%), brocket (73.2 ± 1.1%), and Maxwell's duikers (73.0 ± 2.8%), and significantly lower (P = 0.0167) in bay duikers (67.1 ± 4.3%). There were significant differences among species in digestibilities of neutral-detergent fiber, hemicellulose, and cellulose, but they did not follow body size differences, since larger species were expected to show higher digestion coefficients for fiber compared to smaller species. The type of fiber fed may have influenced these results. Frugivores may be adapted to a diet of soluble fibers, as might be found in wild fruits, instead of the insoluble fibers in the diet fed. Passage trials were conducted on the two smallest species. The mean transit time for pudu was 29.9 ± 0.8 hr, and for the Maxwell's duiker was 42.2 ± 6.4 hr. © 1996 Wiley-Liss, Inc.     

Primates are an important food resource for leopards (Panthera pardus) in Mahale,Tanzania

Leopard diets in the Kasoje area of the Mahale Mountains National Park, Tanzania, were analysed by inspecting prey remains in 256 scats. This area is unique as leopard density is high despite a relatively low density of medium-sized ungulates, regarded as the most preferred prey of leopards. At least eleven prey mammal species were confirmed in the scats. Small prey mammals up to 10 kg comprised 91.4% of the relative biomass consumed; the mean prey biomass in each scat was 7.6 kg. Blue duiker (31.2%) was the most dominant prey species, followed by the red colobus (29.2%), semi-terrestrial Cercopithecinae (the vervet monkey and yellow baboon combined) (10.5%) and the red-tailed monkey (9.9%). At the order level, the most consumed prey taxon was Primates (53.8%), followed by Cetartiodactyla (39.6%) and Rodentia (5.8%). Among primates, the blue monkey was the most preferred prey species, followed by the red colobus and semi-terrestrial Cercopithecinae. High consumption of primates is a unique characteristic of the leopards in Mahale. This trend exemplifies the flexibility of leopards in their choices of prey, and such flexibility may be one of the underlying reasons for leopards exhibiting the broadest global distribution among all wild felid species.     

A bioeconomic analysis of bushmeat hunting

Unsustainable bushmeat hunting is a major threat to mammal species, particularly in West/Central Africa. We developed a multispecies dynamic simulation model of hunter behaviour, parameterized using data from the Ashanti region, Ghana. The model distinguishes between two hunting techniques, snaring and gun hunting. We analyse the impact of key economic parameters on off-takes. Economic incentives determine the effort devoted to hunting, the choice of hunting technique, and the species that are consumed domestically or traded in markets. These factors, together with the growth rates and catchabilities of hunted species, determine the ecological impact of hunting. The results suggest that increased bushmeat prices are likely to lead to a switch from snaring, which is cheaper but less efficient, to gun hunting, with a consequent impact on vulnerable species. Increases in agricultural prices have an ambiguous effect on hunter behaviour, depending on the balance between incentives to invest in agriculture and increased consumption as incomes improve. Penalties are more effective if they target bushmeat sales, rather than the act of hunting. This model represents a step forward because it explicitly considers bushmeat as a component of the household economy. This has important implications as regards the development of policies to conserve species hunted for bushmeat.     

Barcoding bushmeat: molecular identification of Central African and South American harvested vertebrates

The creation and use of a globally available database of DNA sequences from a standardized gene region has been proposed as a tool for species identification, assessing genetic diversity and monitoring the legal and illegal trade in wildlife species. Here, we contribute to the Barcode of Life Data System and test whether a short region of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene would reliably distinguish among a suite of commonly hunted African and South American mammal and reptile species. We used universal primers to generate reference barcode sequences of 645 bp for 23 species from five vertebrate families (Crocodilidae, Alligatoridae, Bovidae, Suidae and Cercopithecidae). Primer cocktails yielded high quality barcode sequences for 179 out of 204 samples (87.7%) from all species included in the study. For most taxa, we sequenced multiple individuals to estimate intraspecific sequence variability and document fixed diagnostic characters for species identification. Polymorphism in the COX1 fragment was generally low (mean = 0.24%), while differences between congeneric species averaged 9.77%. Both fixed character differences and tree-based maximum likelihood distance methods unambiguously identified unknown and misidentified samples with a high degree of certainty. Barcode sequences also differentiated among newly identified lineages of African crocodiles and identified unusually high levels of genetic diversity in one species of African duiker. DNA barcoding offers promise as an effective tool for monitoring poaching and commercial trade in endangered species, especially when investigating semi-processed or morphologically indistinguishable wildlife products. We discuss additional benefits of barcoding to ecology and conservation.     

Targeted detection of mammalian species using carrion fly‐derived DNA

DNA analysis from carrion flies (iDNA analysis) has recently been promoted as a powerful tool for cost‐ and time‐efficient monitoring of wildlife. While originally applied to identify any mammalian species present in an area, it should also allow for targeted detection of species and individuals. Using carrion flies captured in the Taï National Park, Côte d'Ivoire, we assessed this possibility by (i) screening carrion fly DNA extracts with nonspecific and species‐specific PCR systems, respectively, targeting mitochondrial DNA (mtDNA) fragments of any mammal or of Jentink's duiker (Cephalophus jentinki), three colobine monkeys (subfamily Colobinae) and sooty mangabey (Cercocebus atys); and (ii) genotyping carrion fly extracts containing sooty mangabey mtDNA. In comparison with the nonspecific PCR assay, the use of specific PCRs increased the frequency of detection of target species up to threefold. Detection rates partially reflected relative abundances of target species in the area. Amplification of seven microsatellite loci from carrion flies positive for sooty mangabey mtDNA yielded an average PCR success of 46%, showing that the identification of individuals is, to some extent, possible. Regression analysis of microsatellite PCR success and mtDNA concentration revealed that, among all carrion flies analysed for this study, 1% contained amounts of mammal mtDNA sufficient to attempt genotyping with potentially high success. We conclude that carrion fly‐derived DNA analysis represents a promising tool for targeted monitoring of mammals in their natural habitat.     

Market Hunting in the Taï Region,Côte d’Ivoire and Implications for Monkey Populations

We studied the effect of market hunting on primate species in the Taï National Park and adjacent forests in Côte d’Ivoire. We assessed the impact of hunting by comparing the calculated maximal reproduction rate with the current off-take rate. We assessed the average bushmeat consumption per capita/per year from weekly investigations on bushmeat available in 88 bushmeat restaurants and markets over a 12-mo period in 1999. We derived data on preferences for particular game species from interviews of 162 bushmeat consumers, 25 subsistence hunters and 3 groups of professional hunters. Hunting pressure was highest on the larger primate species such red colobus (Procolobus badius), black- and- white colobus (Colobus polykomos) and sooty mangabeys (Cercocebus atys). The amount of primate bushmeat extracted from the Taï National Park and surrounding forests was 249,229 kg in 1999. We estimated population densities using line transect surveys. By referring to current population densities we calculated the maximum production of each species using the Robinson Redford model (2001) and assuming unhunted conditions. A comparison of current harvest levels with maximum production suggests that harvest of Procolobus badius is sustainable, whereas current off-take of Colobus polykomos, Cercocebus atys, Cercopithecus diana (diana monkey) and C. campbelli (Campbell’s monkeys) exceeds sustainability by ≤3 times. We recommend that wildlife managers promote programs that encourage the production of domestic animals as a substitute for wild meat.     

Mammalian Diet and Broad Hunting Strategy of the Dingo (Canis familiaris dingo) in the Wet Tropical Rain Forests of Northeastern Australia1

The diet of dingoes (Canis familiaris dingo) in the Australian Wet Tropics was examined by analyzing 383 dingo scats collected throughout the region for the presence of mammal prey remains. The scats yielded 29 native and 4 introduced mammal prey species from 14 families. The most important species in terms of percentage occurrence in the scats were Melomys cervinipes (22.2%), hoodon macrourus (17.0%), Perameles nasuta (12.5%), and Thylogale stigmatica (12.5%). The most important families were Muridae (37.1%), Peramelidae (29.5%), and Macropodidae (25.8%). Examination of small‐scale habitat preferences revealed species that preferentially use the forest edge ranked significantly higher in the diet than those that do not, and species that are terrestrial ranked higher in the diet than those that are arboreal. Relative abundance was also a significant factor in the ranked dietary occurrence of each species, with abundant species ranked significantly higher than those that are less abundant. These results suggest that dingoes in the Australian Wet Tropics are opportunistic predators of a wide variety of mammal species, with abundant terrestrial and forest edge‐dwelling taxa the most susceptible to predation.     

The influence of body-size and diet on road-kill trends in mammals

Roads negatively impact animals in a variety of ways. One of the most obvious impacts is vehicle-induced mortality. We have little understanding of the patterns and rates of road mortality for mammals. The aims of this study were to determine representative road-kill rates for local mammal species, compare road-kill rates between mammals of different sizes and diets, and compare patterns of road mortality between seasons. We hypothesized that carnivores would be killed less often than herbivores or omnivores and that medium sized mammals (1.0–10.0 kg) would be killed more often than expected based on their frequency in the area. At least 50% of the mammal species in the study area were impacted by road mortality, representing 21 species from 5 mammalian orders. Carnivores were found less often and medium-sized mammals more often than predicted. Porcupines (Erithizon dorsatum), raccoons (Procyon lotor), cottontails (Sylvilagus floridanus) and striped skunks (Mephitis mephitis) were the most frequent species to be killed. On average, 3.8 mammals were killed per 100 km of road. The road-kill rate varied between seasons and species and peaked in mid June. We also looked across studies to determine general rates of vehicle-induced mortality for mammals and found that an average of 8.8 mammals are killed per 100 km. Given the rapid decline of many mammal species and the consistent increase in vehicle miles traveled, efforts to preserve roadless areas and develop strategies to mitigate the effects of roads on mammals are warranted.     

Decline in hunter offtake of blue duikers in Bioko Island,Equatorial Guinea

The blue duiker (Philantomba monticola) is an abundant and widely distributed ungulate in continental sub‐Saharan Africa. High hunting pressure throughout its range may be particularly threatening to the persistence of island populations of the species. In this study, we assessed offtake of blue duikers in Pico Basilé, Bioko Island, Equatorial Guinea. We recorded the number of animals shot or snared by 46 commercial hunters over a 33‐month period, and the location (elevation) of each animal hunted. From this, we estimated catch per hunter (C_H), catch per hunting day (C_D) and catch per unit effort (CPUE). The number of duikers shot or snared across the study period, significantly declined within the mid‐altitude range (901–1500 m). There were no significant drops in C_H or CPUE at low or high altitudes for snared animals. The ratio of immature‐to‐adult animals hunted increased significantly over time within the mid‐altitude range. We suggest that these trends in offtake, especially in the more heavily hunted mid‐altitudes of the study area, indicate a decline in the population within this range. If this situation is widespread throughout the island, it is likely that unregulated bushmeat hunting will have devastating consequences to the biodiversity of Bioko Island, particularly for heavily hunted species that are naturally less abundant.     

Environmental relationships of the brush-tailed rabbit-rat, Conilurus penicillatus, and other small mammals on the Tiwi Islands, northern Australia

Aim To describe the habitat characteristics and status of the brush‐tailed rabbit‐rat, Conilurus penicillatus Gould, 1842, on the Tiwi Islands, northern Australia, as part of a broader programme aimed at the conservation management of this species. In addition, comparable environmental modelling is undertaken for other co‐occurring small native mammals, including the black‐footed tree‐rat, Mesembriomys gouldii Gray, 1843, a taxonomically and ecologically related species. These objectives relate to the significance for mammal conservation of islands generally in Australia, and the recent intensification of plantation forestry on these previously little‐disturbed islands. Location Melville and Bathurst islands (Tiwi Islands), respectively, Australia's second and fifth largest islands. Methods A systematic survey was conducted for mammals across Bathurst (115 sampled quadrats) and Melville Island (236 quadrats). A broad range of environmental variables was recorded for every quadrat. All quadrats were classified by their woody plant species composition. The relative occurrence of individual mammal species across the resulting vegetation groups was examined using Kruskal–Wallis anova . The habitat relationships of C. penicillatus and the most commonly recorded mammal species were described by generalized linear modelling, with separate models for each island, for both islands combined, for all habitats and for only those sites dominated by eucalypts. Results Twelve small mammal species (excluding bats, macropods and feral animals) were recorded in this study. The most notable feature of this survey was the lack of records of M. gouldii from Bathurst Island. In contrast, the proportion of quadrats with C. penicillatus was not significantly different between the two islands. There was no significant tendency for these two species to co‐occur in quadrats on Melville Island more or less commonly than by chance. Conilurus penicillatus was most abundant in eucalypt forest while M. gouldii showed a weak association with eucalypt forests and woodlands and shrub land. The five most commonly recorded species showed highly idiosyncratic relationships with environmental variables, with this relationship showing some variation between the two islands. None showed any significant association with floristic variation within the extensive eucalypt forests, but most showed significant associations with tree height, basal area (especially of large trees), landscape position (distance to watercourse) and fire history. Main conclusions Conilurus penicillatus was most likely to occur in tall eucalypt forest away from watercourses. This habitat is now being targeted for clearance for the development of plantations of the exotic Acacia mangium. Seven of the 12 mammal species examined in this study (C. penicillatus, M. gouldii, Rattus tunneyi Thomas, 1904, Melomys burtoni Ramsay, 1887, Sminthopsis butleri Archer, 1979, Phascogale tapoatafa Meyer, 1793 and Petaurus breviceps Gould, 1842) were not recorded at all in plantations, and these (and other) species are likely to be severely disadvantaged by plantation development. The study also demonstrated that the two medium to large arboreal rodent species (C. penicillatus and M. gouldii) vary in environmental associations and found no evidence that C. penicillatus increased in areas unoccupied by M. gouldii.