Due to its large size, the gorilla has only two major predators. Humans are by far the main predator of G. gorilla, killing animals for their meat, and body parts and in retaliation for damage to crops. Leopards are important predators at some sites, with G. gorilla accounting for 4–9% of biomass consumed.
Gorilla gorilla, like G.beringei, is prone to many pests and diseases.
Conservation IUCN Category is Critically Endangered.
The main threats are commercial game hunting (largely facilitated by logging activities) and disease (in particular the Ebola virus). Since the 1970s, vast tracts of remote forest with high densities of G. g.gorillas became accessible thanks to the implementation of a logging system roads and the availability of logging trucks and other vehicles. With this opening up of the range of G. g.gorilla, a large number of advertisements, hunters, loggers, and other people have entered the region, and logging camps and villages have been established.
Logging of primary forests is expected to continue over much of the G. g.gorilla habitat with the result that all large tracts of the forest will eventually be exposed to logging and commercial bushmeat hunting. It is estimated from 1983 to 2000, the number of western gorillas in Gabon declined by about 56%, mainly due to commercial hunting.
The last threat to G. g. gorilla is a disease, especially the Ebola virus. Since the early 1990s, Ebola has caused several massive G. g. gorilla die-offs in the most remote parts of the species’ range These include some of the most important places for the preservation of G. g. gorilla; Lopé NP, Minkébé NP, and Mwagné forest block in Gabon, and Odzala N. P. in NW Congo.
The Ebola epizootic wave is moving east approx. 45km/year. Therefore, Ebola is expected to affect most of the remaining range of G. g. gorilla within the next decade. Ebola causes ca. 95% mortality within populations of a western gorilla.
A conservative estimate is that 33% of the total population of the protected area of gorillas has been killed by Ebola over the past 13–14 years. In short, since the early 1980s, hunting the bushmeat trade and Ebola virus outbreaks have largely eliminated G.gorilla native to large areas of intact forest and has caused a rapid decline in numbers.
While it is hoped that the sites mentioned above that have been affected by commercial hunting and Ebola will eventually recover, there remain a few strongholds.
Among these is the Sangha Trinational Complex of Central African Republic, Cameroon, and Congo, the Lac Télé/Likouala complex in Congo, the Dja Conservation Complex and Boumba-Bek/Nki Complex in Cameroon, and the Loango/Moukalaba-Doudou/ Gamba Complex in Gabon Tourism based on Gorilla sighting increases in the range of G. gorilla, but this areas need to be closely monitored.
G. g. diehli is known as one of the most endangered primates. Most of the surviving 250–300 individuals of G. g. diehli are in 11 small subpopulations occasionally linked by immigration, and most are outside of protected areas and engulfed by a dense human population. Thus, this subspecies is at risk from inbreeding, and various human activities (e.g.hunting loss of habitats, and diseases).
In Nigeria, G. g.diehli is located in the Okwangwo of Cross River N.P. and Afi Mountains Wildlife Sanctuary, but fragmentation, degradation, and loss of habitat to agriculture continue at a rapid rate, even within the Cross River N. P. In Cameroon.
G. g. diehli occurs in the Kagwene Gorilla Sanctuary and in the ‘proposed’ Takamanda N. P. All four of these sites, additional sites and connecting lowland sites, need to be protected and effectively managed.