Mountain gorilla census involves counting and recording the overall mountain gorilla population. The most recent mountain gorilla census was conducted in 2018 as part of the Bwindi-Sarambwe population surveys under the transboundary framework of the Greater Virunga Transboundary Collaboration.
This effort involved protected area authorities in Uganda and the Democratic Republic of Congo, namely the Uganda Wildlife Authority (UWA) and l’Institut Congolais pour la Conservation de la Nature (ICCN).
The census was supported by several organizations, including:
- Rwanda Development Board
- Gorilla Conservation Programme
- Mammalian Ecology and Conservation Unit of the UC Davis Veterinary Genetics Laboratory
- Max Planck Institute for Evolutionary Anthropology
- The Dian Fossey Gorilla Fund
- Institute of Tropical Forest Conservation
- Wildlife Conservation Society Uganda Office
- Gorilla Doctors
- Conservation Through Public Health
- Fauna and Flora International
- Partners in Conservation at Columbus Zoo and Aquarium
- WWF
- Bwindi Mgahinga Conservation Trust
According to the 2018 survey documentation, a total of 459 mountain gorillas (Gorilla beringei beringei) were recorded, marking the largest mountain gorilla population ever documented in the transboundary Bwindi-Sarambwe ecosystem.
This included 50 groups and 13 solitary individuals. In comparison, the 2011 survey recorded an estimate of 400 individual gorillas in 36 groups and 16 solitary individuals.
This marked the 15th gorilla population census for the area and the first to include the Sarambwe Nature Reserve.
The recent census followed the methodology used in the previous census in the Virunga Massif. Teams walked predetermined paths, covering the entire forest areas in search of gorilla signs, other key mammals, and evidence of human activities.
Procedures for Detecting Fresh Gorilla Signs
If fresh gorilla signs were detected, the following steps were taken:
- Following the gorilla trail to locate recent nest sites.
- Collecting fecal samples from the nests.
- Conducting genetic analysis to determine individual genotypes.
The census was conducted in two phases. The first phase took place from March to May 2018, lasting 62 days. The second phase was carried out from October to December 2018, lasting 60 days. This two-phase approach ensured that any undetected gorillas from the first phase would be found and included in the second phase.
Other Findings
Other selected mammal species, such as elephants and chimpanzees, were also studied, along with evidence of human activities such as tree cutting. However, due to study limitations, no population declines were recorded for these species.
The mountain gorilla census revealed an increase in the number of mountain gorillas, demonstrating the success of conservation efforts to protect this endangered species.
