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We synthesize information on parameters useful for managing the hunting of two common mammal species that are important for local people in the Neotropics and Africa: Cuniculus paca and Philantomba monticola , respectively. We highlight the scarcity of data available on the parameters needed to manage these two species sustainably. As most of the studies were conducted > 40 years ago, we stress the need to supplement the information available using methodological and technical innovations. In particular, we call for new assessments covering the possible variations in parameter values across the species' distribution ranges, and covering various anthropogenic contexts, to test density-dependent and compensatory processes that may explain the resilience of these species to hunting. [ABSTRACT FROM AUTHOR]

The main goal of this article is to present a flexible statistical modelling framework to deal with multivariate count data along with longitudinal and repeated measures structures. The covariance structure for each response variable is defined in terms of a covariance link function combined with a matrix linear predictor involving known matrices. In order to specify the joint covariance matrix for the multivariate response vector, the generalized Kronecker product is employed. We take into account the count nature of the data by means of the power dispersion function associated with the Poisson-Tweedie distribution. Furthermore, the score information criterion is extended for selecting the components of the matrix linear predictor. We analyse a data set consisting of prey animals (the main hunted species, the blue duiker Philantomba monticola and other taxa) shot or snared for bushmeat by 52 commercial hunters over a 33-month period in Pico Basilé, Bioko Island, Equatorial Guinea. By taking into account the severely unbalanced repeated measures and longitudinal structures induced by the hunters and a set of potential covariates (which in turn affect the mean and covariance structures), our method can be used to indicate whether there was statistical evidence of a decline in blue duikers and other species hunted during the study period. Determining whether observed drops in the number of animals hunted are indeed true is crucial to assess whether species depletion effects are taking place in exploited areas anywhere in the world. We suggest that our method can be used to more accurately understand the trajectories of animals hunted for commercial or subsistence purposes and establish clear policies to ensure sustainable hunting practices. Supplementary materials accompanying this paper appear online. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the role that Pleistocene refugia, rivers and local habitat conditions may have played in the evolutionary diversification of three central African duiker species (Cephalophus dorsalis, C. callipygus and Philantomba monticola). Genetic data from geo-referenced feces were collected from a wide range of sites across Central Africa. Historical patterns of population genetic structure were assessed using a ~ 650 bp fragment of the mitochondrial control region and contemporary patterns of genetic differentiation were evaluated using 12 polymorphic microsatellite loci. Results: Mitochondrial analyses revealed that populations of C. callipygus and P. monticola in the Gulf of Guinea refugium are distinct from other populations in west central Africa. All three species exhibit signatures of past population expansion across much of the study area consistent with a history of postglacial expansion. There was no strong evidence for a riverine barrier effect in any of the three species, suggesting that duikers can readily cross major rivers. Generalized dissimilarity models (GDM) showed that environmental variation explains most of the nuclear genetic differentiation in both C. callipygus and P. monticola. The forest-savanna transition across central Cameroon and the Plateaux Batéké region in southeastern Gabon show the highest environmentally-associated turnover in genetic variability. A pattern of genetic differentiation was also evident between the coast and forest interior that may reflect differences in precipitation and/or vegetation. Conclusions: Findings from this study highlight the historical impact of Pleistocene fragmentation and current influence of environmental variation on genetic structure in duikers. Conservation efforts should therefore target areas that harbor as much environmentally-associated genetic variation as possible in order to maximize species' capacity to adapt to environmental change. [ABSTRACT FROM AUTHOR]

Across the Congo Basin, human hunting pressure poses the biggest threat to small- and medium-bodied forest ungulates (genus Philantomba and Cephalophus, commonly known as duikers). The exploitation of these species has cascading effects on larger ecosystem processes, as well as on human subsistence practices. This study compares encounter rates and estimated population densities of duiker species, specifically Philantomba monticola (blue duiker) in the Dzanga-Sangha Protected Areas ( APDS), Central African Republic ( CAR). Data were collected using direct observations of individual animals during diurnal (135 km) and nocturnal (150 km) transects in the APDS, with abundance estimates produced using DISTANCE software. Transect data demonstrate that within hunted forests similar to APDS, nocturnal rather than diurnal transects yield more individual observations of ungulates. Despite hunting pressure in the region, estimates presented for APDS suggest some of the highest density estimates reported for blue duikers in western and central Africa (58.6 blue duikers per km2). This study directly contributes current regional data on the status of duiker populations at APDS and in the larger Sangha Trinational Landscape ( TNS, UNESCO). More broadly, we highlight the potential importance of nocturnal transect data to the development of adaptive management regimes in hunted forests. [ABSTRACT FROM AUTHOR]

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 ( CH), catch per hunting day ( CD) 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 CH 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. [ABSTRACT FROM AUTHOR]

Aders' duiker Cephalophus adersi is a critically endangered small antelope endemic to the coastal forests of east Africa. Threatened by habitat loss and hunting, the species was until recently known to persist only on Zanzibar, Tanzania, and in the Arabuko-Sokoke National Reserve, Kenya. However, more recent observations, have confirmed the occurrence of Aders' duiker in Kenyan coastal forests north of the Tana River. This paper reports systematic camera trapping results for three sites in the Boni-Dodori coastal forest system north of the Tana and the only other known mainland site for Aders' duiker, the Arabuko-Sokoke forest. From a total survey effort of 5,723 camera trap days, we demonstrated that the known area of occurrence for Aders' duiker has more than doubled with occupancy values at or close to 100 % for all three northern sites. An index of relative abundance for Aders' duiker was also one to two orders of magnitude greater at these sites compared to Arabuko-Sokoke. Application of a replicate count N-mixture model to camera trap data from Boni National Reserve resulted in an estimate of 7.3 Aders' duikers/km (95 % CI 4.5-10.1/km). The results also indicate higher densities of suni Nesotragus moschatus and Harvey's duiker Cephalophus harveyi in the northern forests relative to Arabuko-Sokoke. Blue duiker Philantomba monticola was recorded at low density in Arabuko-Sokoke forest but not detected at the northern sites. These findings significantly improve the conservation prospects for Aders' duiker and highlight the global importance of the northern coastal forests of Kenya. [ABSTRACT FROM AUTHOR]

Across West and Central Africa, duikers are important for trade and consumption; their populations are expected to become depleted. Reliable data on their status are scanty in Nigeria. We assessed duiker populations in the Oban Sector of Cross River National Park through diurnal and nocturnal surveys along 32 transects of 2 km each. After 508-km survey effort, only Ogilby's duiker ( Cephalophus ogilbyi) and blue duiker ( Philantomba monticola) were recorded. Using habitat as a covariate in modelling detection probability in DISTANCE 6.0, we estimated densities for the blue duiker ranging from 15.5 (95% CI: 7.8-30.9) in the core, 5.8 (CI: 2.6-12.9) in the buffer and 0.9 (CI: 0.09-10.1) km² in farm fallow to no duikers in the plantation. For Ogilby's duiker, densities ranged from 1.6 (95% CI: 0.7-3.7) km² in the core, 2.0 (CI: 0.8-5.1) in buffer to no duikers in farm fallow and plantation. The apparent absence of yellow-backed and Bay duikers may indicate local depletion. We call on all stakeholders to rise up to the challenge of rescuing this biological hotspot in Nigeria from further degradation and species loss through improved funding for well-equipped field staff and institutionalized community wildlife management. [ABSTRACT FROM AUTHOR]