Search

Human-wildlife conflict, in particular crop-foraging, challenges conservationists worldwide. Endangered golden monkeys (Cercopithecus mitis kandti) are frequent crop-foragers around Volcanoes National Park (VNP), Rwanda. To evaluate the impact of crop-foraging behaviour on monkeys and farmers, we interviewed 45 farmers near VNP using a structured questionnaire and organised a workshop for local and regional actors to discuss mitigation measures. To investigate differences in monkey behaviour when foraging inside versus outside VNP, and to inform mitigation strategies, we collected ad libitum behavioural data from one habituated golden monkey group for 11 weeks. We tested the feasibility of a taste aversion technique to deter monkeys, by placing chilli-laced potatoes in harvested potato fields adjacent to the study group's home range but found that experimental aversion techniques were logistically challenging. Of 38 farmers, 95% experienced potato loss to monkeys and 36% of 44 farmers threw objects at/chased monkeys in the previous farming season. Farmers and workshop participants judged the most effective way to mitigate crop-foraging to be through improvement of existing crop-guarding. Behavioural observations indicated increased vigilance behaviour and decreased social behaviour when in farmland. Monkeys (N = 9) that visited the experimental area avoided chilli-laced potatoes but continued to forage on nearby crops. In conclusion, our results indicate that crop-foraging can negatively impact farmers' livelihoods and attitudes and can increase vigilance behaviour of monkeys. Our multi-faceted approach enabled the involvement of a wide range of stakeholders, highlighted the urgent need to improve existing management measures and explored alternatives to facilitate positive coexistence between monkeys and farmers. [ABSTRACT FROM AUTHOR]

Objectives: Studying reproductive seasonality helps us understand changes in the energetically demanding periods of pregnancy and lactation. We investigated how diet variability and key food plant phenology relate to mating and birth seasonality in both remaining populations of endangered golden monkeys in the Virunga massif and the Gishwati forest in Rwanda. Material and Methods: Using scan and ad libitum sampling, we recorded feeding, mating, and births in two social groups (K and M) living in Volcanoes National Park (VNP), in the Virunga massif, from 2004 to 2018, and in one group (G) in the Gishwati forest in 2017–2018. We also monitored bamboo shoot and fruit availability in the groups' home ranges in 2017–2018. Results: Mating was observed year‐round but peaked four to 6 months prior to each group's respective birth season. Despite the two VNP groups ranging only 16 km apart, they had different birth seasons. Females from group K gave birth during the late bamboo growing season, from September to December, while females from group M gave birth during the early bamboo shooting season, from February to April. This pattern was linked to differences in the availability and consumption of bamboo shoots between low‐elevation (group K) and high‐elevation (group M) habitat. In group G, births occurred from March to April, coinciding with the period of high fruit availability and consumption in the Gishwati forest. Discussion: Our findings suggest that food availability shapes golden monkey birth seasons, even at a small spatial scale. Current changes in key food plant regeneration, potentially driven by climate change, need to be closely monitored to inform golden monkey conservation management. [ABSTRACT FROM AUTHOR]

Habitat loss and fragmentation are major threats to primate populations globally. The Endangered golden monkey Cercopithecus mitis kandti is only found in two small forest fragments: the Virunga massif in Rwanda, Uganda and the Democratic Republic of the Congo, and the Gishwati Forest in Rwanda. Little is known about the abundance and distribution of this subspecies, or threats to its survival. During 2007–2018, we collected data along 893.7 km of line transects and 354.2 km of recce trails in Volcanoes National Park and in Gishwati–Mukura National Park to estimate golden monkey density and examine any threats. In Volcanoes National Park, golden monkeys were found almost exclusively in the bamboo zone, and in Gishwati–Mukura National Park they occurred only in the remnant tropical montane Gishwati Forest. In Volcanoes National Park, density was estimated to be 7.89 (95% CI: 3.85–16.19), 5.41 (2.64–11.08), and 5.47 (3.68–8.14) groups per km2 in 2007, 2011 and 2017–2018, respectively. This corresponds to a total of 4,331 individuals (95% CI: 2,723–5,938) in 2007, 4,487 (2,903–6,071) in 2011 and 4,626 (4,165–5,088) in 2017–2018. In Gishwati Forest, group density averaged 1.98 (95% CI: 1.27–3.16) per km2, corresponding to 172 (95% CI: 154–190) individuals in 2017–2018. Survey results from Volcanoes National Park suggest that the golden monkey population has been stable during 2007–2018. Limited habitat, illegal activities such as harvesting of bamboo and firewood, and the presence of feral dogs, threaten the golden monkey in Rwanda and require continued monitoring. The development of a conservation action plan is a priority to protect this species. [ABSTRACT FROM AUTHOR]

Land-use change is the main driver of habitat loss and fragmentation for primates, resulting in declines in species diversity and population size. The Gishwati-Mukura landscape in Rwanda, home to endemic and threatened primate species, is characterized by heavily degraded and fragmented forest fragments, including one remnant tropical montane forest, one restored forest, and several forests planted in the mid-1980s with exotic species. A landscape restoration project was launched in 2014 to restore and protect this landscape and improve human wellbeing. From June to August 2019, we assessed the use of remnant, restored, and exotic forest patches by primates in this landscape. Using 15 line transects and 7 reconnaissance surveys, we compared distribution and abundance of Endangered golden monkeys (Cercopithecus mitis kandti), Vulnerable L'Hoest's monkeys (Allochrocebus lhoesti), and Endangered eastern chimpanzees (Pan troglodytes schweinfurthi) between remnant tropical montane forest and restored forest and ascertained the presence of primates in planted forest patches in the Gishwati-Mukura landscape. We interviewed farmers (N = 97) to assess the frequency of human-primate conflicts associated with the remnant and restored forests. We found that all three primate species occupied the remnant tropical montane forest, chimpanzees and golden monkeys occurred in the restored forest, and only golden monkeys inhabited the exotic planted forest fragments. For all three species, encounter rates were higher in the remnant tropical montane forest than in the restored and planted forest fragments. The restored forest provided additional habitat for primates, and efforts to restore degraded forest appear to have reduced conflicts between communities and primates. [ABSTRACT FROM AUTHOR]

Many primates exhibit behavioral flexibility which allows them to adapt to environmental change and different habitat types. The golden monkey (Cercopithecus mitis kandti) is a little‐studied endangered primate subspecies endemic to the Virunga massif and the Gishwati forest in central Africa. In the Virunga massif, golden monkeys are mainly found in the bamboo forest, while in the Gishwati forest they live in mixed tropical montane forest. Here we describe and compare the diet of golden monkeys in both fragments. Over 24 consecutive months from January 2017 we used scan sampling to record feeding and ranging behavior of two Virunga groups and one Gishwati group totaling ca. 240 individuals. We also examined the phenology of bamboo and fruit trees, key seasonal food plant species for the monkeys. Golden monkeys fed on more than 100 plant species. The Virunga groups were mostly folivorous (between 72.8% and 87.16% of the diet) and fed mostly on young bamboo leaves and bamboo shoots, while 48.69% of the diet of the Gishwati group consisted of fruit from 22 different tree and shrub species. Bamboo shoots and fruit are seasonally available foods and were consumed regularly throughout the period when they were available. Despite being the smallest of the three study groups, the Gishwati group had a larger home range area (150.07 ha) compared to both Virunga groups (25.24 and 91.3 ha), likely driven by the differences in availability and distribution of fruit and bamboo in the habitats. Like other blue monkey subspecies, golden monkeys appear to have a flexible dietary strategy enabling them to adjust diet and ranging behavior to local habitats and available food resources. Additional studies and continuing conservation efforts are needed to better understand how variation in feeding and ranging ecology affects reproduction, population growth, and carrying capacity. Research highlights: Great dietary flexibility enabled golden monkeys to adapt to a folivorous diet dominated by bamboo leaves and shoots in the fruit‐scarce forest of Volcanoes National Park, and a frugivorous diet in Afromontane forest of Gishwati, in Rwanda.Golden monkey ranging strongly related to diet: the smaller, mainly frugivorous group in Gishwati forest had a larger home range size than both larger groups with folivorous diets in Volcanoes National Park.Conservation efforts for this Albertine Rift endemic and Endangered primate are essential to protect both populations in Rwanda, where habitat loss and illegal human activities persist, and a reduction of bamboo regeneration has been documented. [ABSTRACT FROM AUTHOR]

The future of primates depends on conservationists in primate range countries having the education and opportunities needed to facilitate conservation efforts. However, most primates are found in countries where conservation is underfunded. Rwanda is home to 14 primate species, with three being listed as endangered on the International Union for Conservation of Nature (IUCN) Red List. Their remaining native habitats are scarce, highly fragmented, and surrounded by high human densities. Lacking education opportunities and the loss of qualified individuals following decades of political instability created a need for well‐trained conservationists to tackle conservation challenges in Rwanda. The Memoirs Program, a science capacity‐building partnership between Dian Fossey Gorilla Fund (DFGF), University of Rwanda (UR), the Rwanda Development Board, and Cleveland Metroparks Zoo, aims to train the next generation of Rwandan conservationists. Annually, the Memoirs Program provides 10–12 top students from the UR Conservation Biology undergraduate program the opportunity to conduct senior research projects (Memoirs) at DFGF addressing conservation issues in and around Rwanda's protected areas. Students receive one‐on‐one supervision by DFGF scientists and affiliates to supplement UR mentorship, along with targeted teaching modules that reinforce and complement UR curricula. In continuation of the Memoirs Program, participants are offered professional development, employment opportunities, and support to publish their research in peer‐reviewed journals. Since inception of the Program in 2003, 123 students have participated with 83% being employed or pursuing higher education degrees in conservation‐related fields in Rwanda and the region. Pre‐ and post‐training comparison of oral presentation skills, one of the teaching modules, involving 22 students demonstrated increased post‐training performance. The Memoirs Program represents an effective partnership between the government, an international conservation non‐governmental organization, and a public higher‐learning institution in a developing country to support high‐performing students to become tomorrow's conservation leaders. This model could be replicated within Rwanda and in other regions of the world. Research Highlights: Science capacity‐building that leverages the strengths of academic, governmental, and non‐governmental institutions helps to develop Rwanda's new generation of conservation leaders and scientists.More than 80% of participants are today active in fields of conservation in Rwanda and the region. [ABSTRACT FROM AUTHOR]

Increasing population density can increase infectious disease risk and thus reduce population growth and size. Host-parasite interactions of threatened animals that remain in small protected forest fragments therefore need to be monitored carefully. Due to extreme conservation efforts, the mountain gorilla (Gorilla beringei beringei) population in the 450-km2 Virunga Massif has more than doubled since 1973, reaching 604 individuals in 2016. To better understand changes in the transmission risks of soil-borne and other enteric pathogens for mountain gorillas, we determined defecation outputs of different age-sex classes and the diurnal variation in feces deposition. We weighed 399 wet fecal samples deposited at nest sites and on trails between nest sites by gorillas of varying age and sex, determined by lobe diameter, from five social groups (n = 58 gorillas) that range in the Volcanoes National Park, Rwanda. We found increasing daily average defecation outputs with increasing age-sex class (infants, 435 g; juveniles, 1346 g; medium-sized gorillas, 2446 g; silverbacks, 3609 g). Gorillas deposited two– to threefold the amount of feces at nest sites compared to on trails, suggesting that nest sites may function as hotspots for enteric pathogen infections through direct contact or when gorillas ingest foods contaminated with infectious larvae during site revisits in intervals matching the maturation period of environmentally transmitted gastrointestinal parasites. In combination with ranging and demographic data, these findings will enable the modeling of spatiotemporal variation in soil contamination and infectious disease risk for Virunga gorillas as their population density continues to increase. [ABSTRACT FROM AUTHOR]

Premise: Paleontologists use tooth form to assess diets of fossil mammals. Plants would also be expected to adapt their morphology to respond to herbivory. Fossil nettle leaves with definitive stinging trichomes (tribe Urticeae, family Urticaceae) are described from the early Eocene upland lacustrine floras of the Okanogan Highlands, British Columbia, Canada. This is the first report of stinging trichomes in the fossil record. Their occurrence in western North America at a time of major large herbivorous mammal radiation suggests they acted, as they do today, as a deterrent for mammal herbivory. Methods: Fossil leaf compressions and extant leaves were photographed with standard methods. Focus‐shift stacking was used to layer photos of the fossil leaves. Results: Urticaceous fossil leaves from the Okanogan Highlands greatly resemble their modern relatives in leaf morphology and particularly in both stinging and nonstinging trichomes. Nettles are common components of the flora of the Volcanoes National Park in Rwanda. This region is used as a modern analogue for the Okanogan Highlands, based on comparable elevation, equable conditions that host both similar floras and large folivores. Conclusions: Nettles in tribe Urticeae (Urticaceae) producing leaves with stinging and nonstinging trichomes were already present in the early Eocene of western North America at a pivotal time during the early radiation of modern mammalian herbivore groups. They offer tantalizing evidence of a selective response that plants may have developed to protect themselves from the evolving mammalian herbivores of that time. [ABSTRACT FROM AUTHOR]

Monitoring population size and growth over time is vital for the conservation of endangered species. Mountain gorillas Gorilla beringei beringei remain in two small populations that span the borders of the Democratic Republic of Congo, Rwanda and Uganda. Each population contains two subpopulations that receive differing levels of protection: the monitored groups are visited daily by park staff and researchers and can be counted by sight, whereas the number and growth rate of unmonitored gorillas must be estimated indirectly. Here, we re‐analyze published data from a survey in 2010 combined with new results from a survey conducted during two sampling occasions in 2015 and 2016 to estimate mountain gorilla abundance and growth in the Virunga Massif between 2010 and 2016. Using genetic analysis of non‐invasively collected samples and two capture–mark–recapture estimates, we estimated that the 186 detected genotypes represented 221 (95% credible interval: 204–243) to 251 (205–340) unmonitored gorillas in 2016. Together with the 418 monitored gorillas, the overall population of the Virunga Massif thus reached 639 (622–661) to 669 (623–758) individuals. We estimated the growth of the entire Virunga Massif population at about 3% per year, but determined that the growth of the monitored gorillas (4.4%) mainly drove that increase. In contrast, the trend of the unmonitored subpopulation could not be determined with confidence because both models provided 95% CI that encompassed zero: 0.5% per year (−0.7% to +1.7%) and 1.1% (−2.7% to +4.4%). While the overall growth rate represents a rare success story for primate conservation, our results highlight the need for greater protection of unmonitored gorillas. [ABSTRACT FROM AUTHOR]

Humans were once considered unique in having a concept of death but a growing number of observations of animal responses to dying and dead conspecifics suggests otherwise. Complex arrays of behaviors have been described ranging from corpse removal and burial among social insects to quiet attendance and caregiving among elephants and primates. Less frequently described, however, are behavioral responses of individuals from different age/sex classes or social position toward the death of conspecifics. We describe behavioral responses of mountain gorillas (Gorilla beringei beringei) to the deaths of a dominant silverback and a dominant adult female from the same social group in Volcanoes National Park in Rwanda and the responses of Grauer's gorillas (Gorilla b. graueri) to the corpse of an extra-group silverback in Kahuzi-Biega National Park, Democratic Republic of Congo. In gorillas, interactions between groups or with a lone silverback often result in avoidance or aggression. We predicted that: (i) more individuals should interact with the corpses of same-group members than with the corpse of the extra-group silverback; (ii) adult females with infants should avoid the corpse of the extra-group silverback; and (iii) in the mountain gorilla cases, individuals that shared close social relationships with the dead individual should spend more time with the corpse than other individuals in the group. We used a combination of detailed qualitative reports, photos, and videos to describe all occurrences of affiliative/investigative and agonistic behaviors observed at the corpses. Weobserved similar responses toward the corpses of group and extra-group individuals. Animals in all three cases showed a variety of affiliative/investigative and agonistic behaviors directed to the corpses. Animals of all age/sex classes interacted with the corpses in affiliative/investigative ways but there was a notable absence of all adult females at the corpse of the extra-group silverback. In all three cases, we observed only silverbacks and blackbacks being agonistic around and/or toward the corpses. In the mountain gorilla cases, the individuals who spent the most time with the corpses were animals who shared close social relationships with the deceased. We emphasize the similarity in the behavioral responses around the corpses of group and extragroup individuals, and suggest that the behavioral responses were influenced in part by close social relationships between the deceased and certain group members and by a general curiosity about death. We further discuss the implications close interactions with corpses have for disease transmission within and between gorilla social groups. [ABSTRACT FROM AUTHOR]

The spatial distribution of species has long sparked interest among ecologists and biogeographers, increasingly so in studies of species responses to climate change. However, field studies on spatial patterns of distribution, useful to inform conservation actions at local scales, are still lacking for many regions, especially the tropics. We studied elevational trends and species‐area relationships among anurans in wetland habitats within Volcanoes National Park (VNP) in Rwanda, part of the biodiverse Albertine Rift region. In VNP, wetlands are key sites for anuran reproduction, and anurans are likely threatened by wetland desiccation which has occurred for the last few decades. Between 2012 and 2017, we sampled anuran communities in ten VNP wetlands located along an elevational gradient of c. 600 m (from 2,546 to 3,188 m a.s.l.) and found at least eight species, including at least two Albertine Rift Endemics. We show that species richness, diversity, and abundance likely decline with a decrease in wetland size and with an increase in elevation, though additional sampling (e.g., at night) might be needed to derive definite conclusions. Larger wetlands at lower elevations contained most species and individuals, which indicates the potential threat of wetland size reduction (through desiccation) for anuran conservation. However, we also found that wetlands differed in species composition and that some species (e.g., Sclerophrys kisoloensis) were likely restricted in distribution to only a few of the smaller wetlands—suggesting that the conservation of each individual wetland should be prioritized, regardless of size. We propose that all wetlands in VNP require additional conservation measures, which should be based on knowledge gathered through long‐term monitoring of anuran communities and research on drivers of wetland decline. Only such extended research will allow us to understand the response of anurans in VNP to threats such as climate change and wetland desiccation. [ABSTRACT FROM AUTHOR]

• We compare several immunoassay options for assessing hormones in wild mountain gorillas. • All assays for fecal androgen and glucocorticoid metabolites showed acceptable internal validity. • Correlations between assays for the same metabolites ranged between 0.42 and 0.88. • Assays for wildlife researchers, along with commercial options, captured natural hormonal increases. • Assay performance varies across species, manufacturers, and contexts. Wildlife researchers seeking to non-invasively examine endocrine function in their study species are presented with a dense and technical 'garden of forking paths' to navigate between collecting a biological sample and obtaining a final measurement. In particular, the choice of which enzyme immunoassay (EIA) to use with collected fecal samples, out of the many options offered by different manufacturers and research laboratories, may be one of the most consequential for final results. However, guidance for making this decision is still emerging. With this gap in mind, we performed a head-to-head comparison of results obtained from four different EIAs for fecal glucocorticoid metabolites (FGCMs), and three different EIAs for fecal androgen metabolites (FAMs), applied to the same set of fecal samples collected from the mountain gorillas (Gorilla beringei beringei) monitored by the Dian Fossey Gorilla Fund in Volcanoes National Park, Rwanda. We provide a) an analytical validation of the different EIAs via tests of parallelism and linearity; b) an estimate of inter-assay correlation between EIA kits designed for the same metabolites; and c) a test of the kits' ecological validity, in which we examine how well each captures endocrine changes following events that theory predicts should result in elevated FGCM and/or FAM concentrations. Our results show that kits differ to some degree in their performance; at the same time, nearly all assays exhibited at least moderate evidence of validity and covariance with others for the same analyte. Our findings, which differ somewhat from similar comparisons performed in other species, demonstrate the need to directly assess assay performance in a species- and context-specific manner as part of efforts to develop the burgeoning discipline of wildlife endocrinology. [ABSTRACT FROM AUTHOR]

The morphology of Prototapirella fosseyi n. sp., P. rwanda n. sp. and P. gorillae Imai, Ikeda, Collet, and Bonhomme, 1991 in the Entodiniomorphida were described from the mountain gorillas, Gorilla beringei beringei , in Rwanda. The ciliates have a retractable adoral ciliary zone, four non-retractable ciliary tufts in four caudalia, and one broad skeletal plate beneath the body surface. P. rwanda has a dorsal lobe and ventral lobes in two rows whereas P. fosseyi has no lobes. These two new species have an elongated body, a flat tail flap leaning to the ventral, a macronucleus with a tapering anterior end, a round posterior end and a shallow depression on the dorsal side, a micronucleus lying near the anterior end of macronucleus, a thin left region of the skeletal plate, a distinct skeletal rod plate, and four contractile vacuoles. P. gorillae has some variations in the nuclei and the skeletal plate. The infraciliary bands of three Prototapirella species were the same as some Triplumaria species; a C-shaped adoral polybrachykinety, a slender perivestibular polybrachykinety, and paralabial kineties in their retractable adoral ciliary zone and short lateral polybrachykineties in their four caudalia. The perivestibular polybrachykinety is joined only to the right end of adoral polybrachykinety. [ABSTRACT FROM AUTHOR]

Recently, a high number of Entodiniomorphida species was discovered in Virunga mountain gorillas (Gorilla beringei beringei) in Rwanda compared to other primates. Thirteen species of five genera (Troglocorys , Gorilloflasca , Prototapirella , Troglodytella , and Opisthotrichum) were identified with 10 species in Gorilloflasca , Prototapirella , and Troglodytella being host-specific, to our current knowledge. The remaining three species have been described for other herbivorous mammals; Prototapirella gorillae for western lowland gorillas; Troglocorys cava for western lowland gorillas, chimpanzees, and guinea baboons; Opisthotrichum janus in the family Ophryoscolecidae is regarded as specific to African antelopes. Here, we show the first indication that wild herbivorous hindgut fermenting mammals might have rumen ophryoscolecids in the intestine sympatric with their native intestinal ciliates. We also describe three new Prototapirella species, P. sabyinyo , P. sulcata , and P. curiosa. The somatic ciliary zones of the three new species are atypical of Prototapirella while their buccal infraciliature is not different from that of other Prototapirella species. [ABSTRACT FROM AUTHOR]