Raquel Costa, Valéria Romano, André S. Pereira, Jordan D. A. Hart, Andrew J.J. MacIntosh, Misato Hayashi

Gorilla tourism supports the protection of the gorilla ecosystem, benefiting humans and wildlife populations living therein. Assessing to what degree the presence and proximity of tourists affect wildlife aids long-term benefits. Because wild animals might see human activities as stressors, we hypothesised that the increased presence and proximity of tourists leads to an immediate increase in gorilla social cohesion. We constructed social networks from association rates before, during and after tourist visits, and when tourists were very close (≤ 3m) or close (> 3m). Our analysis focused on this small distance threshold (≤ 3m and > 3m) because the 7m rule enforced by the national park was violated 84% of the time. Our analysis showed that gorillas spent more time in closer association after tourists arrived and when they were in very close (< 3m away). Immediate changes were detected in the number of individuals close to each other, the time they spent together and the distance of an individual to all other individuals indicate that gorillas might increase social cohesion because they perceive tourists as a risk. These results highlight the need to enforce the tourism guidelines (maximum of 8 people per group, including park staff, and a minimum distance of 7m).