Mapping suitable great ape habitat in and around the Lobéké National Park, South-East Cameroon

As a result of extensive data collection efforts over the last 20-30 years, there is quite a good understanding of the large-scale geographic distribution and range limits of African great apes. However, as human activities increasingly fragment great ape spatial distribution, a better understanding of what constitutes suitable great ape habitat is needed to inform conservation and resource extraction management. Chimpanzees (Pan troglodytes troglodytes) and gorillas (Gorilla gorilla gorilla) inhabit the Lobéké National Park and its surrounding forest management units (FMUs) in South-East Cameroon. Both park and neighboring forestry concessions require reliable evidence on key factors driving great ape distribution for their management plans, yet this information is largely missing and incomplete. This study aimed at mapping great ape habitat suitability in the area and at identifying the most influential predictors among three predictor categories, including landscape predictors (dense forest, swampy forest, distance to water bodies, and topography), human disturbance predictors (hunting, deforestation, distance to roads, and population density), and bioclimatic predictor (annual precipitation). We found that about 63% of highly to moderately suitable chimpanzee habitat occurred within the Lobéké National Park, while only 8.4% of similar habitat conditions occurred within FMUs. For gorillas, highly and moderately suitable habitats occurred within the Lobéké National Park and its surrounding FMUs (82.6% and 65.5%, respectively). Key determinants of suitable chimpanzee habitat were hunting pressure and dense forest, with species occurrence probability optimal at relatively lower hunting rates and at relatively high-dense forest areas. Key determinants of suitable gorilla habitat were hunting pressure, dense forests, swampy forests, and slope, with species occurrence probability optimal at relatively high-dense and swampy forest areas and at areas with mild slopes. Our findings show differential response of the two ape species to forestry activities in the study area, thus aligning with previous studies.

Effects of Land cover change on Great Apes distribution at the Lobéké National Park and its surrounding Forest Management Units, South-East Cameroon. A 13 year time series analysis

Understanding the effects of land cover change on wildlife distribution is very important for resource management and conservation planning. This paper aimed at detecting the effects of land cover change on great apes distribution at the Lobéké National Park and its bounded forest management units (FMUs). Data on great ape nests were collected in the field for the years 2001 and 2014 through distance sampling with line transects. Landsat TM images of South-East Cameroon for the years 2001 and 2014 were acquired from earth explorer and corrected atmospherically for proper visualization. An area of interest comprising the Lobéké National Park and its FMUs was extracted for classification and change detection. A comparison in great apes nest distribution and change per land cover change category was done for both years through point pattern analysis, whereas a time series analysis of the detected land cover change impacts on great apes nest distribution for a period of 13 years was modeled using logistic growth and regression equations in Vensim 7.2. The results could illustrate that, as land cover changes from one cover type in 2001 to another in 2014, increases or decreases in great apes nests were observed within each changed area.

Protected areas in tropical Africa: assessing threats and conservation activities

Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natural resources. However, significant threats from anthropogenic activities and decline of wildlife populations persist, while conservation efforts in most PAs are still minimal. We assessed the impact level of the most common threats to wildlife within PAs in tropical Africa and the relationship of conservation activities with threat impact level. We collated data on 98 PAs with tropical forest cover from 15 countries across West, Central and East Africa. For this, we assembled information about local threats as well as conservation activities from published and unpublished literature, and questionnaires sent to long-term field workers. We constructed general linear models to test the significance of specific conservation activities in relation to the threat impact level. Subsistence and commercial hunting were identified as the most common direct threats to wildlife and found to be most prevalent in West and Central Africa. Agriculture and logging represented the most common indirect threats, and were most prevalent in West Africa. We found that the long-term presence of conservation activities (such as law enforcement, research and tourism) was associated with lower threat impact levels. Our results highlight deficiencies in the management effectiveness of several PAs across tropical Africa, and conclude that PA management should invest more into conservation activities with long-term duration.

Hunting, law enforcement, and African primate conservation

Primates are regularly hunted for bushmeat in tropical forests, and systematic ecological monitoring can help determine the effect hunting has on these and other hunted species. Monitoring can also be used to inform law enforcement and managers of where hunting is concentrated. We evaluated the effects of law enforcement informed by monitoring data on density and spatial distribution of 8 monkey species in Taï National Park, Côte d'Ivoire. We conducted intensive surveys of monkeys and looked for signs of human activity throughout the park. We also gathered information on the activities of law-enforcement personnel related to hunting and evaluated the relative effects of hunting, forest cover and proximity to rivers, and conservation effort on primate distribution and density. The effects of hunting on monkeys varied among species. Red colobus monkeys (Procolobus badius) were most affected and Campbell's monkeys (Cercopithecus campbelli) were least affected by hunting. Density of monkeys irrespective of species was up to 100 times higher near a research station and tourism site in the southwestern section of the park, where there is little hunting, than in the southeastern part of the park. The results of our monitoring guided law-enforcement patrols toward zones with the most hunting activity. Such systematic coordination of ecological monitoring and law enforcement may be applicable at other sites.

Long-term research sites as refugia for threatened and over-harvested species

The presence of researchers, ecotourists or rangers inside protected areas is generally assumed to provide a protective effect for wildlife populations, mainly by reducing poaching pressure. However, this assumption has rarely been empirically tested. Here, we evaluate and quantify the conservation benefits of the presence of a long-term research area in Taï National Park, Côte d'Ivoire. A wildlife survey following 225 km of line transects revealed considerably higher primate and duiker encounter rates within the research area when compared with adjacent areas. This positive effect was particularly pronounced for threatened and over-harvested species, such as the endangered red colobus monkey (Procolobus badius). This pattern was clearly mirrored by a reversed gradient in signs of poaching, which decreased towards and inside the research area, a trend that was also supported with park-wide data. This study demonstrates that even relatively simple evidence-based analytical approaches can bridge the gap between conservation theory and practice. In addition, it emphasizes the value of establishing long-term research sites as an integral part of protected area management.

Pandemic human viruses cause decline of endangered great apes

Commercial hunting and habitat loss are major drivers of the rapid decline of great apes [1]. Ecotourism and research have been widely promoted as a means of providing alternative value for apes and their habitats [2]. However, close contact between humans and habituated apes during ape tourism and research has raised concerns that disease transmission risks might outweigh benefits [3-7]. To date only bacterial and parasitic infections of typically low virulence have been shown to move from humans to wild apes [8, 9]. Here, we present the first direct evidence of virus transmission from humans to wild apes. Tissue samples from habituated chimpanzees that died during three respiratory-disease outbreaks at our research site, Côte d'Ivoire, contained two common human paramyxoviruses. Viral strains sampled from chimpanzees were closely related to strains circulating in contemporaneous, worldwide human epidemics. Twenty-four years of mortality data from observed chimpanzees reveal that such respiratory outbreaks could have a long history. In contrast, survey data show that research presence has had a strong positive effect in suppressing poaching around the research site. These observations illustrate the challenge of maximizing the benefit of research and tourism to great apes while minimizing the negative side effects.