Modification of natural areas by human activities mostly has a negative impact on wildlife by increasing the geographical and ecological overlap between people and animals. This can result in escalating levels of competition and conflict between humans and wildlife, for example over crops. However, data on specific crops and crop parts that are unattractive to wildlife yet important for human livelihoods are surprisingly scarce, especially considering their potential application to reducing crop damage by wildlife. Here we examine the co-utilization of a nationally important and spatially abundant cash crop, cashew Anacardium occidentalis, by people and chimpanzees Pan troglodytes verus inhabiting a forested–agricultural matrix in Cantanhez National Park in Guinea-Bissau. In this Park people predominantly harvest the marketable cashew nut and discard the unprofitable fruit whereas chimpanzees only consume the fruit. Local farmers generally perceive a benefit of raiding by chimpanzees as they reportedly pile the nuts, making harvesting easier. By ensuring that conflict levels over crops, especially those with high economic importance, remain low, the costs of living in proximity to wildlife can potentially be reduced. Despite high levels of deforestation associated with cashew farming, these findings point to the importance of cashew as a low-conflict crop in this area.

This survey was part of a situational analysis of bushmeat hunting and trade in Sapo National Park in south-east Liberia. Increased private-sector investment in natural resource extraction and industrial-scale agribusiness outside the Park is anticipated to increase hunting pressure and lead to further declines in biodiversity unless informed, assertive actions are taken to protect it more effectively. Two commercial hunting camps on the Park's southern boundary were surveyed for 1 month each. Information on the catch of all professional hunters in these camps was documented. The results revealed a high diversity of species but significant and probably unsustainable bushmeat extraction rates. Eighty-two chimpanzees Pan troglodytes verus, including eight live infants, were recorded in the survey. Most of the bushmeat harvested was destined for Monrovia and other major towns. A concerted effort needs to be made to shut down these commercial camps but the potentially significant contribution that commercial trade makes to urban areas suggests that this can only be achieved if Liberia develops alternative sectors in domestic meat production to feed the growing urban population.

Pan troglodytes vellerosus, the Nigerian-Cameroon chimpanzee, is the most recently recognized chimpanzee subspecies and is categorized as Endangered on the IUCN Red List. Current estimates, based on a range of sources, suggest the total number of individuals to be between 5,000–8,000. This study used a transect survey to estimate the population of P. t. vellerosus within the Nigerian submontane forest of Ngel Nyaki Forest Reserve, in Taraba State. The forest is an isolated fragment of c. 7.5 km2. Total nest building population size (n = 12.5) and population density (1.67 weaned chimpanzees km-2) were estimated from the number of nests observed along line transects. The maximum nest-group size (n = 11) suggests that this population comprises a single community. The low estimated population numbers within Ngel Nyaki forest, compounded by the forest's isolated location, highlight the urgent need for conservation action.

The effectiveness of protected area management is a major concern. In Taï National Park, Côte d'Ivoire, recurrent human pressure challenges the ability of law enforcement authorities to protect wildlife. During 2010–2015 we studied the implementation of law enforcement in the Park to determine (1) the potential for improvement of the protection of large mammals and (2) the minimum patrolling effort needed to obtain increases in their populations. We recorded presence of large mammals and illegal activities in two areas within the Park, the research area (210 km2) and the rest of the Park (5,150 km2), and compiled data about patrolling efforts from the Park authorities. Using a generalized linear mixed model we identified a relationship between increased patrolling effort and the relative abundance of large mammals, especially for monkey groups, pygmy hippopotamuses Choeropsis liberiensis and duikers. At low patrolling efforts duiker encounter rates remained stable, whereas rates of encounter with monkey groups and pygmy hippopotamuses decreased. Chimpanzee Pan troglodytes verus encounter rates were slower to respond and remained stable at higher patrolling effort, but decreased at low patrolling effort. Our findings suggest that a minimum of 1.32 patrol days per km2 over 2 years is required for chimpanzee and monkey populations to increase, whereas a patrolling effort of 0.48 days per km2 over 2 years would lead to an increase in duiker and pygmy hippopotamus populations. We maintain that the patrolling effort required to ensure an increase in wildlife can be estimated relatively precisely from multi-year biomonitoring programmes.

Taraba State, Nigeria, is an important conservation site for the Endangered Nigeria–Cameroon chimpanzee Pan troglodytes ellioti. Gashaka Gumti National Park, Nigeria's largest national park and home to potentially the largest contiguous population of the Nigeria–Cameroon chimpanzee, spans a significant portion of the eastern sector of Taraba and the adjoining Adamawa State. South of the Park, Ngel Nyaki Forest Reserve comprises two forest fragments and holds a small population of chimpanzees. We investigated the existence of patterns in population structure and dispersal within this region, using microsatellite loci extracted from non-invasive sources of DNA. Our results indicate that dispersal and thus gene flow between the groups of chimpanzees at the Park and Reserve is limited, at least more so than it is within the Park, and we identified a biased sex ratio at the Reserve, forewarning of potential conservation concerns in relation to demographic and genetic stochasticity. We discuss conservation actions that may be applicable to sustaining the population within Ngel Nyaki Forest Reserve.

A main concern of farmers worldwide is how to reduce crop losses to wildlife. Some potentially lethal crop protection methods are non-selective. It is important to understand the impact of such methods on species of conservation concern. Uganda has important populations of Endangered eastern chimpanzees Pan troglodytes schweinfurthii. Farmers sometimes use large metal mantraps to guard their fields against crop-raiding wildlife, particularly baboons Papio anubis and wild pigs Potamochoerus sp.. Chimpanzees that range onto farmland also step in these illegal devices and without rapid veterinary invention face severe injury or eventual death. Unlike inadvertent snaring of great apes in African forests, the problem of mantraps in forest–farm ecotones has received little attention. We report 10 cases of entrapped chimpanzees in the cultivated landscape surrounding Uganda's Budongo Forest during 2007–2011, undoubtedly only a portion of the actual number of cases. Mantraps currently present a substantial threat to ape populations in this important conservation landscape. Our data underscore the need for conservation programmes to consider the techniques used by rural farmers to protect their livelihoods from wild animals.

Liberia has the largest blocks of continuous forest in West Africa, providing habitat for numerous wildlife species. However, there is a lack of empirical data about the status of Liberia's wildlife populations. During 2010–2012 we conducted the first nationwide survey in Liberia along c. 320 km of systematically located transect lines to estimate the abundance of chimpanzees Pan troglodytes verus, the diversity of large mammals and the nature and degree of anthropogenic threats. With > 7,000 chimpanzees, Liberia is home to the second largest population of West African chimpanzees and is therefore a priority for conservation of the species. Compared to the fragmented populations in other range countries the Liberian population is potentially one of the most viable. Our study revealed that the majority of chimpanzees and some of the most species-diverse mammal communities in Liberia exist outside protected areas. High hunting rates and plans for large-scale exploitation of natural resources necessitate rapid implementation of effective strategies to ensure the protection of one of West Africa's last strongholds for chimpanzees and other rare and threatened mammal species. We provide a country-wide baseline dataset that may serve as a platform for Liberian wildlife authorities, policy-makers and international conservation agencies to make informed decisions about the location and delineation of proposed protected areas, to identify conservation gaps and to devise a conservation action plan to conserve Liberia's wildlife resources.

The 2009–2010 Sierra Leone National Chimpanzee Census Project estimated there was a population of 5,580 chimpanzees Pan troglodytes verus distributed across the country, with > 50% occurring outside protected areas. The census also highlighted the significance of competition between people and chimpanzees for resources in areas dominated by farming activities where wild chimpanzees forage on crops. We selected four study areas in two districts in Sierra Leone with high chimpanzee density in habitats dominated by agriculture, far from any protected areas. Our objectives were to assess farmers’ perceptions of the main challenges to their agricultural yields, and the wildlife involved in crop foraging, and their perceptions of chimpanzees in particular, as well as the main crop protection measures used. We conducted 257 semi-structured interviews with local farmers across the four study areas. We found that (1) farmers reported wild animals as the main challenge to their agricultural practices; (2) most complaints concerned cane rats Thryonomys swinderianus, which targeted almost all crop types, especially rice and cassava; (3) chimpanzees reportedly targeted 21 of the 23 crop types cultivated, but did so less often than cane rats, focusing particularly on oil palm, cassava and domestic fruits; (4) overall, chimpanzees were not among the top three most destructive animals reported; (5) chimpanzees were generally perceived as being more destructive than dangerous and as having declined since before the civil war; and (6) the main crop protection measure employed was fencing interspersed with traps. Our findings show the importance of investigating farmers’ perceptions to inform the development of appropriate conservation strategies aimed at promoting coexistence of people and wildlife in degraded landscapes.

Habitat loss and fragmentation, hunting pressure, and human–wildlife conflict threaten the survival of primates across Africa. Particularly dramatic forest losses have occurred outside protected areas in the Guinean forest–savannah transition zone. Using the Boé region, Guinea-Bissau, as a case study, we investigated whether and how this rapidly humanized mosaic of wooded savannah, gallery forests and cropland could sustain viable primate populations. We conducted line transect surveys and reconnaissance (recce) walks to assess populations of one Critically Endangered (chimpanzee Pan troglodytes verus), one Endangered (Temminck's red colobus Piliocolobus badius temminckii), one Vulnerable (king colobus Colobus polykomos), and one Near Threatened (sooty mangabey Cercocebus atys) arboreal primates across a 104 km2 section of Boé in the dry season of 2016. Using the standing crop nest count method we estimated a relatively high chimpanzee density (0.77 individuals per km2, 95% CI 0.45–1.34). An assessment of habitat selection showed that chimpanzees prefer semi-dense forest and fallow fields with remnant old trees for nesting, and locations close to rivers. The other primates studied occurred in extremely low densities and were largely restricted to gallery forests. Our results indicate a need for immediate action to ensure the long-term survival of the primate community in the human-dominated landscape of Boé. Our recommendations include action to maintain hunting pressure at a low level, restoring and protecting gallery forests, introducing incentives for farmers for forest protection and primate-friendly practices, and extending the conservation programme to all arboreal primates in the region.