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This case reports the successful management of a traumatic diaphyseal femoral fracture in an infant Western chimpanzee (Pan troglodytes verus) from a rescue centre in Sierra Leone using a 2.4-mm intramedullary pin and two 2.7-mm String of Pearls™ locking plates. Locking plate use has not been previously described in chimpanzees.

Species distributions are influenced by processes occurring at multiple spatial scales. It is therefore insufficient to model species distribution at a single geographic scale, as this does not provide the necessary understanding of determining factors. Instead, multiple approaches are needed, each differing in spatial extent, grain, and research objective. Here, we present the first attempt to model continent-wide great ape density distribution. We used site-level estimates of African great ape abundance to (1) identify socioeconomic and environmental factors that drive densities at the continental scale, and (2) predict range-wide great ape density. We collated great ape abundance estimates from 156 sites and defined 134 pseudo-absence sites to represent additional absence locations. The latter were based on locations of unsuitable environmental conditions for great apes, and on existing literature. We compiled seven socioeconomic and environmental covariate layers and fitted a generalized linear model to investigate their influence on great ape abundance. We used an Akaike-weighted average of full and subset models to predict the range-wide density distribution of African great apes for the year 2015. Great ape densities were lowest where there were high Human Footprint and Gross Domestic Product values; the highest predicted densities were in Central Africa, and the lowest in West Africa. Only 10.7% of the total predicted population was found in the International Union for Conservation of Nature Category I and II protected areas. For 16 out of 20 countries, our estimated abundances were largely in line with those from previous studies. For four countries, Central African Republic, Democratic Republic of the Congo, Liberia, and South Sudan, the estimated populations were excessively high. We propose further improvements to the model to overcome survey and predictor data limitations, which would enable a temporally dynamic approach for monitoring great apes across their range based on key indicators.

Aim: Modelling African great ape distribution has until now focused on current or past conditions, while future scenarios remain scarcely explored. Using an ensemble forecasting approach, we predicted changes in taxon-specific distribution under future scenarios of climate, land use and human populations for (1) areas outside protected areas (PAs) only (assuming complete management effectiveness of PAs), (2) the entire study region and (3) interspecies range overlap. Location: Tropical Africa. Methods: We compiled occurrence data (n = 5,203) on African apes from the IUCN A.P.E.S. database and extracted relevant climate-, habitat- and human-related predictors representing current and future (2050) conditions to predict taxon-specific range change under a best- and a worst-case scenario, using ensemble forecasting. Results: The predictive performance of the models varied across taxa. Synergistic interactions between predictors are shaping African ape distribution, particularly human-related variables. On average across taxa, a range decline of 50% is expected outside PAs under the best scenario if no dispersal occurs (61% in worst scenario). Otherwise, an 85% range reduction is predicted to occur across study regions (94% worst). However, range gains are predicted outside PAs if dispersal occurs (52% best, 21% worst), with a slight increase in gains expected across study regions (66% best, 24% worst). Moreover, more than half of range losses and gains are predicted to occur outside PAs where interspecific ranges overlap. Main Conclusions: Massive range decline is expected by 2050, but range gain is uncertain as African apes will not be able to occupy these new areas immediately due to their limited dispersal capacity, migration lag and ecological constraints. Given that most future range changes are predicted outside PAs, Africa's current PA network is likely to be insufficient for preserving suitable habitats and maintaining connected ape populations. Thus, conservation planners urgently need to integrate land use planning and climate change mitigation measures at all decision-making levels both in range countries and abroad.

Ensuring the welfare of captive chimpanzees (Pan troglodytes) is crucial, in part because they can act as a conservation resource in the case of wild populations becoming extinct. One strategy often adopted to ensure animal welfare is environmental enrichment. In this study, we investigated the impact of different nesting materials (leaves and branches, long grass, cotton sheets, and shredded newspaper) upon the welfare of chimpanzees housed at Tacugama Chimpanzee Sanctuary (Sierra Leone). Data was collected on 20 subjects (aged 4 to 15 years) between November 2019 and March 2020. Welfare was based on individuals’ relative frequency of affiliative, abnormal and agonistic behaviours, as well as their social and behavioural competence. We found that individuals’ welfare was higher when presented with nesting materials (compared to the control and post-treatment conditions), particularly when given shredded newspaper, regardless of whether the material was presented separately or in conjunction with another. In addition, welfare was highest: during the morning (vs evening), in groups of older individuals (vs younger), with females engaging in less agonistic behaviours compared to males, and males displaying relatively higher behavioural competence. Our results support previous research that captive chimpanzees be supplied with destructible nesting materials, and demonstrate that synthetic enrichments can indeed have a more positive impact upon welfare than their natural alternatives.

Sierra Leone constitutes the western boundary to the West Africa Upper Guinea Rainforest, one of 35 global biodiversity hotspots. The country is home to the third-largest western chimpanzee (Pan troglodytes verus) population, a subspecies upgraded to Critically Endangered on the 2016 IUCN Red List. The main threats facing chimpanzees in Sierra Leone are habitat loss and increasing interactions with humans. The Mobonda Community Conservation Project (MCCP) is a component of Tacugama Chimpanzee Sanctuary's Community Outreach Program and Kids Environmental Education Program. The aim of MCCP is to promote community-based forest management in combination with wildlife conservation through carefully designed programs that benefit communities, wildlife, and ecologically significant habitats. MCCP also aims to promote self-sustained and integrated community landscape conservation, to facilitate policy discussions to strengthen wildlife laws, and to build the capacity of the Government to implement community-based wildlife and forestry protection projects. Since Tacugama began collecting data in Moyamba District in June 2015, the project has evolved into an assembly of components. MCCP currently works with five communities, running programs including environmental education, ecological research, biomonitoring including wildlife law enforcement, habitat rehabilitation through reforestation of identified wildlife corridors, improved sustainable livelihoods, and ecotourism initiatives. These programs contributed to a reduction in the threats facing wildlife in the area; the project has seen stable chimpanzee numbers where decrements to chimpanzee populations continue to be experienced elsewhere. Other MCCP outcomes include boosted sustainable agricultural production and higher oyster yields while decreasing the negative impact on the mangrove ecosystem allowing it to recover and support an array of important fauna and flora.

AimModelling African great ape distribution has until now focused on current or past conditions, whilst future scenarios remain scarcely explored. Using an ensemble forecasting approach, we predicted changes in taxon-specific distribution under future scenarios of climate, land-use and human population changes.LocationSub-Saharan AfricaMethodsWe compiled occurrence data on African ape populations from the IUCN A.P.E.S. database and extracted relevant human-, climate- and habitat-related predictors representing current and future (2050) conditions to predict taxon-specific distribution under a best- and a worst-case scenario, using ensemble forecasting. Given the large effect on model predictions, we further tested algorithm sensitivity by considering default and non-default modelling options. The latter included interactions between predictors and polynomial terms in correlative algorithms.ResultsThe future distributions of gorilla and bonobo populations are likely to be directly determined by climate-related variables. In contrast, future chimpanzee distribution is influenced mostly by anthropogenic variables. Both our modelling approaches produced similar model accuracy, although a slight difference in the magnitude of range change was found for Gorilla beringei beringei, G. gorilla diehli, and Pan troglodytes schweinfurthii. On average, a decline of 50% of the geographic range (non-default; or 55% default) is expected under the best scenario if no dispersal occurs (57% non-default or 58% default in worst scenario). However, new areas of suitable habitat are predicted to become available for most taxa if dispersal occurs (81% or 103% best, 93% or 91% worst, non-default and default, respectively), except for G. b. beringei.Main ConclusionsDespite the uncertainty in predicting the precise proportion of suitable habitat by 2050, both modelling approaches predict large range losses for all African apes. Thus, conservation planners urgently need to integrate land-use planning and simultaneously support conservation and climate change mitigation measures at all decision-making levels both in range countries and abroad.

Even though information on global biodiversity trends becomes increasingly available, large taxonomic and spatial data gaps persist at the scale relevant to planning conservation interventions. This is because data collectors are hesitant to share data with global repositories due to workload, lack of incentives, and perceived risk of losing intellectual property rights. In contrast, due to greater conceptual and methodological proximity, taxon-specific database initiatives can provide more direct benefits to data collectors through research collaborations and shared authorship. The IUCN SSC Ape Populations, Environments and Surveys (A.P.E.S.) database was created in 2005 as a repository for data on great apes and other primate taxa. It aims to acquire field survey data and make different types of data accessible, and provide up-to-date species status information. To support the current update of the conservation action plan for western chimpanzees (Pan troglodytes verus) we compiled field surveys for this taxon from IUCN SSC A.P.E.S., 75% of which were unpublished. We used spatial modeling to infer total population size, range-wide density distribution, population connectivity and landscape-scale metrics. We estimated a total abundance of 52 800 (95% CI 17 577–96 564) western chimpanzees, of which only 17% occurred in national parks. We also found that 10% of chimpanzees live within 25 km of four multi-national ‘development corridors’ currently planned for West Africa. These large infrastructure projects aim to promote economic integration and agriculture expansion, but are likely to cause further habitat loss and reduce population connectivity. We close by demonstrating the wealth of conservation-relevant information derivable from a taxon-specific database like IUCN SSC A.P.E.S. and propose that a network of many more such databases could be created to provide the essential information to conservation that can neither be supplied by one-off projects nor by global repositories, and thus are highly complementary to existing initiatives.

Human population growth and anthropogenic activities are exacerbating pressures on biodiversity globally. Land conversion is aggravating habitat fragmentation and non-human primates are increasingly compelled to live in forest-agricultural mosaics. In Sierra Leone, more than half of the wild chimpanzee population (Pan troglodytes verus) occurs outside protected areas and competes for resources with farmers. Our study area, in the Moyamba district in south-western Sierra Leone, is practically devoid of forest and is dominated by cultivated and fallow fields, swamps and mangroves. In this region, traditional slash-and-burn agriculture modifies annually the landscape, sparing swamps and mangroves and semi-domesticated oil palms (Elaeis guineensis). This study aimed to explore ecological and anthropogenic factors influencing chimpanzee relative abundance across this highly degraded and human-impacted landscape. Between 2015 and 2016, we deployed 24 camera traps systematically across 27 1.25x1.25 km grid cells. Cameras were operational over a period of 8 months. We used binomial iCAR models to examine to what extent anthropogenic (roads, settlements, abandoned settlements and human presence) and habitat variables (swamps, farmland and mangroves) shape chimpanzee relative abundance. The best model explained 43.16% of the variation with distance to roads and swamps emerging as the best predictors of chimpanzee relative abundance. Our results suggest that chimpanzees avoid roads and prefer to maintain proximity to swamps. There was no significant effect of settlements, abandoned settlements, mangroves or human presence. It appears that chimpanzees do not avoid areas frequented by people; although, our findings suggest temporal avoidance between the two species. We highlight the importance of studying chimpanzee populations living in anthropogenic habitats like agricultural-swamp matrixes to better understand factors influencing their distribution and inform conservation planning outside protected areas., This study was funded by a grant from the Arcus Foundation No. G-PGM-1508-1368 to TH; PA was supported by the MINECO and the Universidad de Castilla-La Mancha (UCLM) through a ‘Ramón y Cajal’ contract (RYC-2012-11970), and Tacugama Chimpanzee Sanctuary provided logistical support.

Like elsewhere in West Africa, the landscapes of Sierra Leone are strongly human-dominated with consequences for large mammal distribution and diversity. Sierra Leone is currently going through a phase of post-war recovery, with accelerating development of the mining, forestry, agricultural and infrastructure sectors. As environmental issues are increasingly considered, comprehensive biodiversity information is required. Here we evaluate spatial patterns of large mammal diversity throughout Sierra Leone to make inferences about species persistence. We used systematic line transect sampling for assessing large mammal distribution. GLMs and canonical correspondence analyses were used to evaluate the relative importance of human impact for every species while controlling for environmental gradients and to make countrywide spatial model predictions. We further developed an algorithm to identify core distributional ranges for the most common species. A total of 562 km of transects were surveyed and 35 large mammal species encountered. Species diversity was impoverished in the country’s south and center and strongly increased towards the north and east. Human impact did not determine the distribution of four species (brushed-tailed porcupine, bushbuck, giant rat, warthog), but was very influential on chimpanzee and yellow-backed duiker occurrence with U-shaped and negative responses, respectively. The remaining species showed mixed responses to human impact and environmental gradients. Predicting species persistence in West African human-dominated landscapes is complex. Pooling of species for land-use planning is therefore not recommended. Our study provides key information for land-use planning to separate areas with post-depletion species assemblages from more diverse regions with high conservation value.

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.

In April 2006, a group of chimpanzees escaped from the Tacugama Chimpanzee Sanctuary in Sierra Leone, resulting in the death of 1 local citizen and injury of another. The chimpanzees caused no further damage after the initial incident. Of the 31 escaped chimpanzees, 27 returned to the sanctuary by the end of 2006, 21 of them voluntarily. The sanctuary is in a forest reserve, a habitat of wild chimpanzees. Ironically, the tragic incident provided an opportunity to observe the behavior of the escaped chimpanzees and their adaptability in the forest. As a result of the incident, local communities could have come to fear the chimpanzees or develop negative feelings toward the sanctuary and its activities, which include keeping a colony of orphaned chimpanzees for rehabilitation and promoting the protection of wild populations. However, collaboration and understanding among the sanctuary, local communities, and government authorities resulted in peaceful handling of the situation and the humane retrieval of 27 of the escaped chimpanzees. As the number of chimpanzees in African sanctuaries increases, they are responsible more than ever for minimizing hazards to surrounding communities. It is important for sanctuaries to develop understanding and to raise support from local communities and government authorities to help them avoid crises and continue their activities.