Mountain gorillas are back from the brink. But what happens if they run out of room?

Humans have helped save the great apes from extinction, but are now the biggest threat to their survival as they compete for land in east Africa’s Virunga mountains• Photographs by Badru Katumba for the GuardianIt is sunrise on mount Muhabura, an inactive volcano on the Ugandan-Rwandan border, and Dr Benard Ssebide is in a rush to find a family of mountain gorillas before the tourists arrive. A mass of ferns, vines and thistles encroaches on the path, and the guides hack through bramb