Kalema-Zikusoka, G. | Search bioRxiv

bioRxiv2026

Tourism impacts on fecal glucocorticoid metabolites of free-ranging mountain gorillas in Bwindi Impenetrable National Park, Uganda

Mountain gorilla tourism plays a vital role in their conservation; however, increasing tourism intensity may elevate gorilla stress levels. Despite this concern, knowledge regarding its physiological effects remains limited. This study non-invasively assessed the impact of tourism on gorilla stress by measuring fecal glucocorticoid metabolites (fGCMs). Fecal samples were collected from habituated gorilla groups in Bwindi Impenetrable National Park, Uganda, between 2017-2018. Concentrations of fGCMs were analyzed using a field-friendly extraction method and enzyme immunoassay. To assess the specific impacts of tourism, we focused on the Rushegura group, which is frequently visited by tourists, and used Bayesian linear mixed-effects models to examine associations between log-transformed fGCMs (log-fGCMs) and tourism intensity (daily tourist numbers and visit frequency). Additionally, we performed a inter-group comparison with the Mubare group, which was visited less frequently but underwent more dynamic social changes, to evaluate how log-fGCMs levels differed across different group contexts. In the Rushegura group, the number of tourists and visits frequently exceeded the maximum limits established by the tourism guidelines (i.e., one visit of eight people per day). In this group, log-fGCMs increased with the number of tourists and were higher during days with multiple visits. The model incorporating visit frequency demonstrated better predictive performance. On the other hand, Mubare gorillas showed higher log-fGCMs than Rushegura gorillas, likely reflecting the influence of social instability. These findings underscore the importance of adhering to the tourism guidelines--specifically regarding group size and visit frequency--to minimize physiological stress and associated risks, such as disease transmission. Although this pilot study lacks site-specific biological validation for this subspecies, the results provide preliminary insights into the physiological stress responses of Bwindi mountain gorillas to tourism. Further long-term, large-scale studies involving multiple gorilla groups are necessary to better understand how tourism and other factors (e.g., habituation status and social factors) influence their stress levels.

ecology↗

bioRxiv2021

Community health and human-animal contacts on the edges of Bwindi Impenetrable National Park, Uganda

Cross-species transmission of pathogens is intimately linked to human and environmental health. With limited healthcare and challenging living conditions, people living in poverty may be particularly susceptible to endemic and emerging diseases. Similarly, wildlife is impacted by human influences, including pathogen sharing, especially for species in close contact with people and domesticated animals. Here we investigate human and animal contacts and human health in a community living around the Bwindi Impenetrable National Park (BINP), Uganda. We used contact and health survey data to identify opportunities for cross-species pathogen transmission, focusing mostly on people and the endangered mountain gorilla. We conducted a survey with background questions and self-reported diaries to investigate 100 participants health, such as symptoms and behaviours, and contact patterns, including direct contacts and sightings over a week. Contacts were revealed through networks, including humans, domestic, peri-domestic, and wild animals for 1) network of contacts seen in the week of background questionnaire completion, 2) network of contacts seen during the diary week. Participants frequently felt unwell during the study, reporting from one to 10 disease symptoms at different intensity levels (maximum of seven symptoms in one day), with severe symptoms comprising 6.4% of the diary records and tiredness and headaches the most common symptoms. Besides human-human contacts, direct contacts with livestock and peri-domestic animals were the most common. Wildlife contacts were the rarest, including one direct contact with gorilla with a concerning timeline of reported symptoms. The contact networks were moderately connected and revealing a preference in contacts within the same species or taxon and within their groups. Despite sightings of wildlife being much more common than touching, one participant declared direct contact with a mountain gorilla during the week. Gorillas were seen very close to six animal taxa (including themselves) considering all interaction types, mostly seen closer to other gorillas, but also people and domestic animals. Our findings reveal a local human population with recurrent symptoms of illness in a location with intense exposure to factors that can increase pathogen transmission, such as direct contact with domestic and wild animals and proximity among animal species. Despite significant biases and study limitations, the information generated here can guide future studies, such as models for disease spread and One Health interventions.

ecology↗