The role of home range use of mountain gorillas in the spread of ebola in the Virunga National Park

Abstract

Gorillas are the closest living relatives of humans after chimpanzees, so ebola and other epidemics can pose the same threat to gorillas. Gorilla Doctors, the only gorilla healing organization in the world, has ordered ebola vaccines for mountain gorillas (Gorilla beringei beringei) in Virunga National Park, which they will want to give to the most vulnerable families, if needed. In order to optimize the vaccination process, we examined 1) the annual home range size of gorilla groups, 2) which groups obtain overlapping home ranges and to what extent, 3) how often gorillas visit outside the park area, where the risk of infection from human is higher. Our study was performed on the basis of data from six gorilla families living in the Virunga National Park, which are still under daily monitoring. Based on their GPS coordinates recorded daily by local rangers between 2014 and 2018, we performed a GIS analysis, during which we characterized the size and location of the annual home ranges using the Minimum Convex Polygon estimation method. The average size of home ranges used by the groups was between 1368 ha and 4150 ha. Although the males leading the groups protect their own families, the analysis revealed that the gorillas do not occupy territory. In many cases, the home ranges of the families overlapped with each other. Average overlaps ranged from 5% to 95%. Gorillas rarely appeared outside the park area, only 1-3 times a year per family. Taking into account our results, a more effective vaccination strategy can be developed, the diseases can be detected more easily in the described families, and the vaccines can be given purposefully in the vulnerable families.