Primates最新文献

To inform regional conservation planning, we assessed mammalian and avian biodiversity in the Djéké Triangle, which is an intact forest with long-term research and tourism focused on western lowland gorillas (Gorilla gorilla gorilla). This critical region serves as a conservation conduit between the Nouabalé-Ndoki National Park (NNNP) in the Republic of Congo and the Dzanga-Ndoki National Park in Central African Republic. Wildlife inventories were conducted to determine if biodiversity in the Djéké Triangle (initially part of a logging concession) was equivalent to the NNNP. Camera traps (CTs) were deployed to estimate species richness, relative abundance, naïve occupancy, and activity patterns of medium-to-large species in mixed species and monodominant Gilbertiodendron forests that comprise the majority of regional terra firma. Species inventories were collected from CTs positioned on a grid and at termite nests throughout the Djéké Triangle and compared to CTs placed in the Goualougo Triangle located within the NNNP. From 10,534 camera days at 65 locations, we identified 34 mammal and 16 bird species. Allaying concerns of wildlife depletion, metrics of species richness in the Djéké Triangle surpassed those of the Goualougo Triangle. Many species were observed to occur across habitats, while others showed habitat specificity, with termite mounds indicated as an important microhabitat feature. Our comparisons of animal activity budgets in different habitat types provide important reference information for other populations and contexts. In conclusion, this study provided empirical evidence of the high conservation value of this region that contributed to increasing the protected status of the Djéké Triangle.

Although western lowland gorillas (Gorilla gorilla gorilla) are the most numerous and widespread gorilla subspecies, they have remained relatively unstudied. International tourism has been initiated at several sites in the Congo Basin, which necessitates habituation of gorillas to human presence. However, habituation has proven difficult due to several obstacles, including relatively low population densities, small group sizes, and thick understory vegetation. In this article, we propose refinements to current approaches to habituating western lowland gorillas that maximize safety and emphasize adaptive responses based on empirical evidence. In addition to reviewing published reports, our approach is informed by the recent habituation of the Mététélé group in the Djéké Triangle, an area that was recently included in the Nouabalé-Ndoki National Park in Republic of Congo. We evaluate progress in habituation according to time spent in the presence of the gorillas and their reactions to humans. The Mététélé group is composed of 14 individuals and has a home range that overlaps with two habituated gorilla groups. Early in the habituation process, we discovered that three of Mététélé's group members were individuals who had previously been habituated as members of other groups. The presence of these individuals expedited the habituation process. Familiarity with humans may have also reduced aggressive responses during the habituation process. The overall result is a refined step-by-step approach to the habituation of western lowland gorillas that includes procedures and assessments to meet best-practice guidelines and ensure the wellbeing of both gorillas and humans.

Food supplementation by humans in peri-urban and urban landscapes can lead to excessive intake of energy and certain macronutrients, and affect animal health. In this study, we evaluated the influence of food supplementation on urinary health indicators in brown howler monkeys (Alouatta guariba) by comparing supplemented and non-supplemented free-ranging peri-urban groups. We also evaluated the effect of sex, day shift, and season of sampling. Between August 2021 and August 2022, we non-invasively collected 61 samples (43 from females and 18 from males) from adult individuals (N = 10) in three supplemented groups and 56 samples (25 from females and 31 from males) from adults (N = 7) in three non-supplemented groups. The supplements, mostly raw foods (e.g., fruits, vegetables, and tubers) and bread, represented 18% of the total fresh mass ingested by the supplemented groups. We assessed pH, density, and the presence of eight urine components (glucose, bilirubin, ketones, protein, urobilinogen, nitrite, blood, and leukocytes) using reagent urine strips. Season of sampling predicted urine density (mean = 1.022), while both season and day shift predicted pH (mean = 6.5). The occurrence of supplementation was a weak predictor of these parameters. Finally, we detected leukocytes in 21% of the 117 samples. We did not identify any visible signs of disease in any individual throughout the study and found no clinical changes in urine under the conditions studied. We urge validation of the results with urine strips to facilitate monitoring of the health of howler monkeys living in anthropogenic landscapes in the presence or absence of dietary supplementation.

Existing protected areas are anchors for conservation. Safeguarding flora and fauna within their peripheral areas is essential to maintaining their integrity and to potential increases to the area under effective conservation. With the decline in tropical forests, initiatives to increase the area of undisturbed forests under strict protection, particularly those neighboring protected areas, is of critical importance. Applied research has informed such land-management decisions for areas surrounding the Nouabalé-Ndoki National Park (NNNP) in Republic of Congo since the park's inception three decades ago. Here, we present results of the first systematic line transect survey of great ape nests conducted in the Djéké Triangle, a 100 km² unlogged continuous forest in the Kabo Forestry Management Unit adjacent to the NNNP. Distance sampling methods applied along 26 line transects on two different occasions (2016 and 2018, with total effort of 69.4 km) provided density estimates of 0.75 (95% confidence interval (CI) 0.52-1.09) and 0.61 (95% CI 0.40-0.92) chimpanzees/km² and 2.15 (95% CI 1.36-3.40) and 1.19 (95% CI 0.78-1.82) gorillas/km² for each of the two surveys, respectively. Estimated ape densities were compared to others across the landscape. The findings provide a unique baseline in an area that supports ongoing behavioral research and future gorilla tourism opportunities in the Djéké Triangle. More importantly, results provided empirical evidence of the environmental value and strategic conservation importance supporting inclusion of the Djéké Triangle into the NNNP in 2023. These long-term monitoring results inform best-practice standards and ape tourism certification.

While there is growing recognition of the importance of traditional knowledge in science, these perspectives remain underrepresented in research publications. However, the synthesis of these approaches has tremendous potential to improve our understanding of wildlife and ecosystems. Toward realizing this aim, we combined local traditional knowledge with molecular classification techniques to investigate "soil scratching" behavior in western lowland gorillas in two localities in Republic of Congo, the Goualougo Triangle and the Djéké Triangle. Daily observations of four gorilla groups for nearly a decade revealed that soil scratching is a foraging strategy to access a deer truffle species, identified here as Elaphomyces labyrinthinus. We also conducted group scans to calculate the time gorillas spent foraging for deer truffles and video focal observations to assess foraging efficiency. There was considerable variation in soil scratching across groups. It was most common in Buka's group, followed by Kingo's group and Mététélé's group. Truffle foraging was rarely observed in the Loya-Makassa group. While the overall distribution of deer truffles seemingly determines the occurrence of this behavior across populations, we found indications of social influences on soil scratching within populations. For example, an adult female transferred from a group in which the behavior was rare to another group where it is common and adjusted her frequencies of soil scratching to that of her new group. Finally, these findings were included in an ecological impact assessment of the Djéké Triangle that prompted conservation managers to shift the location of tourism-associated construction to safeguard this putative cultural behavior.

Fission-fusion social systems allow individuals to make flexible choices about where, with whom, and in what contexts to spend their time in response to competing social and ecological pressures. The ability for fission-fusion societies to support individual behavioral strategies that vary across contexts has been suggested, but the potential function of such context-specific social choices remains largely understudied. We adopted the concept of social niche construction to explore possible differences in social complexity at the individual and group level across feeding contexts. Specifically, we examined patterns of co-attendance across two common ecological contexts in wild Central African chimpanzees (Pan troglodytes troglodytes) in the Goualougo Triangle, Republic of Congo. From data compiled over 6 years, we used multidimensional social network analysis to study the patterns of co-attendance generated from 436 group scans at Ficus and 4527 visits to termite mounds. These two contexts were chosen, because they are both fixed spatial features across the landscape that serve as well-defined points to compare association patterns. We identified context-specific social niche construction in a fission-fusion chimpanzee society that produce different patterns of relationships and social complexity that are consistent in their expression over many years, and offer functional benefits. While enhancing our understanding of chimpanzee behavioral strategies, culture, and conservation, our investigation also indicates that the social niche construction framework aids in elucidating the evolutionary advantages of fission-fusion sociality by accounting for intra- and interindividual variability, cognition, and choice in newfound ways.

Infectious disease is hypothesized to be one of the most important causes of morbidity and mortality in wild great apes. Specific socioecological factors have been shown to influence incidences of respiratory illness and disease prevalence in some primate populations. In this study, we evaluated potential predictors (including age, sex, group size, fruit availability, and rainfall) of respiratory illness across three western lowland gorilla groups in the Republic of Congo. A total of 19,319 observational health assessments were conducted during daily follows of habituated gorillas in the Goualougo and Djéké Triangles over a 4-year study period. We detected 1146 incidences of clinical respiratory signs, which indicated the timing of probable disease outbreaks within and between groups. Overall, we found that males were more likely to exhibit signs than females, and increasing age resulted in a higher likelihood of respiratory signs. Silverback males showed the highest average monthly prevalence of coughs and sneezes (Goualougo: silverback Loya, 9.35 signs/month; Djéké: silverback Buka, 2.65 signs/month; silverback Kingo,1.88 signs/month) in each of their groups. Periods of low fruit availability were associated with an increased likelihood of respiratory signs. The global pandemic has increased awareness about the importance of continuous monitoring and preparedness for infectious disease outbreaks, which are also known to threaten wild ape populations. In addition to the strict implementation of disease prevention protocols at field sites focused on great apes, there is a need for heightened vigilance and systematic monitoring across sites to protect both wildlife and human populations.

The Nouabalé-Ndoki National Park (NNNP) in Republic of Congo has become a beacon for conservation in Central Africa. This manuscript documents the arrival of primatologists, the establishment of field stations and major discoveries in primate behavior and ecology. Field stations were strategically established to study primate behavior in a variety of different contexts from stationary platforms to forest follows of habituated groups. The implementation of new technologies and analyses have also been a hallmark of research at Ndoki. Scientists are shaping a new era in primatology at NNNP by building on past successes and promoting the next generation of Congolese conservationists to address environmental challenges. Results have proven crucial in discussions with government and industry and led to conservation gains such as the inclusion of the intact forests of the Goualougo and Djéké Triangles into the NNNP. The research stations have also become essential for developing a long-term certified sustainable international gorilla tourism program. Despite the many advancements for conservation such as increased protection of forests, development of internationally recognized protocols and large-scale capacity building initiatives, there are reasons for considerable concern in the near- and long-term for primates and their forest habitats in the Ndoki landscape. To address these concerns, we emphasize the long history of forming partnerships with local communities. We also discuss shared overlap featuring multicultural and environmental use of forest resources that is likely to be crucial in championing the conservation of the Ndoki forests for the next 25 years and beyond.