Why is GAFI needed

Gorillas

Background:
The Inner Congo basin seperates the world's two species of gorilla. These are the Eastern Gorilla (Gorilla beringei) which is divided into the Eastern Lowland Gorilla (Gorilla beringei graueri) and the Mountain Gorilla (Gorilla beringei beringei) and the Western Gorilla which is also divided into two subspecies: the western lowland gorilla (Gorilla gorilla gorilla) and the Cross River gorillas (Gorilla gorilla diehli).

DNA research suggests that the two species diverged about 2 million years ago, but with many characteristics in common, they were considered only as subspecies until 2001. Both Eastern Gorillas and Western Gorillas share physical attributes, males weigh about 200kg and females about half their weight. Males are large with maturing males developing distinctive silvering of the hair across their backs and sagittal crests giving them the nick-name ‘Silverbacks’.

Gorillas are able to eat a slightly poorer diet than other great apes as their stomachs are simple and non-fermenting, discouraging them from choosing too many mature leaves to eat. Gorillas diet reflects seasonal changes with ‘specials’ like bamboo shoots featuring when in season.

Gorillas are considered infants until they are weaned at approximately 3 years old, juveniles when they are 6-8 yrs, young or adolescent males (black-backs) when 8-11 yrs. From 12 years onwards they are considered adult and the silvering process on the males will be complete at 16 years old. The oldest mountain gorilla known in the wild was 40 years old and in captivity 53 years. Females reach sexual maturity at 6-7 yrs but have a 2 year period of adolescent streility which allows for a certain amount of experimantation in selecting partners. The first born arrives when a female is 8-9 years old and she cannot have another offspring for 4 years.

Gorillas typically have a group comprising a dominant silverback male, 3 or 4 females and 4 or 5 of their offspring. This simple harem like structure will be the normal one for most groups however all male or multi male groups (where males stay in their natal groups sharing mating rights) also exist. Usually gorillas leave their natal group, taking females with them or remain solitary until they can attract females of their own. Females can also choose to swop groups, especially after the death of a partner, a course of action which can prove risky for infants who accompany them, as they are sometimes killed by the new dominant male. Females' choice of mate seems to be important among the mountain gorillas and is influenced by the males' behaviour, if she doesn’t like it she moves to another group.

Gorillas' social bonds, except those of mother and infants, do not appear to be particularly close. As they get older, infants and juveniles spend more time close to the dominant male until they reach adolescence. Interactions between adults is often limited to vocal exchanges, aggressive displays by males towards female, appeasement of males by females and intervention to end disputes.

Gorillas construct nests to sleep in at night and can learn to use human sign language, but don’t appear to use tools in the wild.. This is possibly due to the fact that gorillas, although living in a group, seldom interact with each other so the skill, even if acquired, may not be passed on. Another explanation offered is that gorillas' diet does not demand much tool use.

Conservation Status:

Eastern Gorillas:
Mountain gorillas have a very small but stable population in several parks. In the Virungas (approximately 380 gorillas in 400 km sq of forest) and in Bwindi (320 gorillas in 200 km sq of forest). Both parks are well supported by international non-government organisations, the scientific community, profitable gorilla-based tourism programmes and the government of the region. These populations are extremely vulnerable as the gene pool is so low, the gorillas are exposed to disease - especially human introduced disease, poaching is still a major threat reduced only by the vigilance of the conservationists. Nevertheless the remaining gorillas are being well cared for.

Eastern lowland gorillas causes much greater concern. In the mid 1990s the population was estimated at 17000 but war engulfed the whole range of the Eastern lowland gorilla. Armies, rebels, refugees and miners all came to live off the land and by 2004 it was reported that thousands of gorillas has been hunted. Bushmeat is still consumed in great quantities and the rebel and military occupation of Bukaru and the accompanying destruction of research equipment at the field station in Kahuzi Biega national Park shows that the situation is not yet stablised. It is unknown what numbers of gorillas remain in DRC or the actions that might realistically be able to be taken which could promote their survival in the wild.

Western Gorillas:
Cross River Gorillas has a estimated total population of 250-280 individuals fragmented across more than 10 highland areas. Despite conservation efforts in recent years the habitat of the Cross River Gorilla is still being lost and the animals are being hunted at low level. At the highest altitudes across the Cross River gorilla range, farming and burning and cattle grazing have produced a mosaic of forest and grassland. Cross River gorillas are shy a a result of hunting so most information comes from research on nest sites , feces and feeding trails. Nest sites suggest fewer than 6 weaned individuals are in a group.

Given their small and fragmented population and the continuing threats to their survival they have been designated as critically endangered on the IUCN Red list. However the prospects for the Cross River gorillas are promising IF they and ther habitat can be protected. Large areas of unoccupied potential gorilla habitat remain, these provide connectivity between the sub populations. To maintain these forest corridors, new protected areas need to be created and local law enforcement needs to be strengthened.

The Western Lowland Gorilla is more difficult to assess as censuses have not been done in these areas recently. The Western lowland gorilla faces an uncertain future due to the increasing scale and cumulative effect of the threats against them. These include forest clearance, logging, bushmeat and disease. Previously remote and therefore inaccessible areas are now open to hunters and loggers who can bring disease with them. Gabon, a former stronghold of the western lowland gorilla lost half its great ape population in 1983-2000 due to hunting and the ebola virus. Large numbers of western lowland gorilla may remain in the Congo basin which in 1983 reported populations in habitat previously considered unsuitable. Gabon is still thought to have the largest number if western lowland gorillas at present.

While additional knowledge will help guide conservation efforts the long term survival of the western lowland gorilla in an increasingly disturbed and human-dominated landscape must depend upon the attitudes of the local people and the partnerships they establish with government and conservationists. Modern approaches to conservation therefore focus on community engagement, education and empowerment as well as global monitoring. The basic concept is that conservation and sustainable development initiatives will be more successful where communities are stronger. Current conservation projects typically work ‘outwards’ from communities to the rest of society and ‘inwards’ from governments towards community level.

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