- Client
- Compagnie des Bauxites de Guinée (CBG), via The Biodiversity Consultancy
- Sector
- Mining
- Location
- Guinea
- Year
- 2025
Estimating chimpanzee numbers for a bauxite mine in Guinea
When the planned survey method could not be used, we adapted the analysis and still delivered a defensible chimpanzee population estimate.
Wetlands and forest in Guinea. © iStock
7,566
camera-trap days analysed
2
seasons compared
92
camera deployments
The challenge
Chimpanzees are a priority species for mining projects that must meet IFC Performance Standard 6. The Biodiversity Consultancy needed a defensible density and population estimate for CBG's project area from existing camera-trap data. However, the planned camera-trap distance sampling method could not be used because too few reference videos were available.
What we did
We analysed dry- and wet-season camera-trap data from 2024: 92 camera deployments and 7,566 camera-trap days in total. We switched to the Random Encounter and Staying Time (REST) model, which does not need reference videos, and modelled occupancy using forest cover, elevation, terrain ruggedness and distance to rivers. We're used to working within the HSE management systems of international mining companies, so analysis like this can be extended into on-site fieldwork without disrupting operations.
The outcome
The Biodiversity Consultancy and CBG received defensible density and population estimates for the project area, with confidence intervals and separate dry- and wet-season figures, all built on a method suited to the data available. Every camera-trap record and verified identification is held in NatureCube, so the estimates can be traced back to the original evidence during lender review.
