Kampala - The population of Uganda's mountain gorillas has grown to 400, up from 302 in 2006, according to a census conducted in 2011, bringing the total number of mountain gorillas in Africa to 880 and giving hope to conservationists trying to save the critically endangered species.Uganda is now home to nearly half of the world's mountain gorillas remaining in the wild, a source of confidence for a country that has come to depend heavily on the popular apes for substantial tourism revenue. The rest of the surviving mountain gorillas - the species Gorilla beringei beringei - are in Congo and Rwanda."The increase in the population of mountain gorillas in Bwindi Impenetrable National Park is testimony to the sound natural resource management policies that are being implemented in the protected areas," Uganda's Ministry of Tourism said in a statement received on Friday. "This result confirms beyond reasonable doubt that Uganda's conservation efforts are paying off."Bwindi Impenetrable National Park, a network of forested jungle deep in the country's south-western frontier, is recognised by Unesco as a heritage site of world value. A permit to track gorillas there costs at least $500 and the World Wide Fund for Nature estimates that each gorilla brings in up to $1m in revenue each year for the East African country.PoachingThe census shows a stunning recovery for a species that once faced a real threat of extinction. Mountain gorillas in the wild still face threats ranging from habitat loss to poaching, especially in Congo, where lawlessness in the country's vast eastern territory has allowed illegal hunters to prosper. Mountain gorillas are hunted for their meat in Congo, according to the WWF.Even a common cold can kill a mountain gorilla, as species is particularly vulnerable to respiratory diseases usually associated with humans.The conservation group Gorilla Doctors said the population growth was partly due to "extreme conservation" methods such as daily ranger monitoring in the forest. Ugandan wildlife officials have been able to build successful partnerships with local communities in part by pouring some of the revenue into local projects, converting previously hostile groups into friendly advocates for the gorillas' survival."The mountain gorilla is the only non-human great ape that is actually growing in number," said Mike Cranfield of Gorilla Doctors. "The growth of the mountain gorilla population can be attributed to the intensive conservation and collaboration between multiple conservation groups and government authorities."