There are two species of gorilla, the western gorilla (Gorilla gorilla) and the eastern gorilla (Gorilla beringei). The western gorilla consists of two recognized subspecies: the Cross River gorilla (Gorilla gorilla diehli) and the western lowland gorilla (Gorilla gorilla gorilla). The Cross River gorilla is classified as Critically Endangered (A4cd) according to the IUCN (2008) Red List (Oates et al., 2008) meaning that it is considered to be facing an extremely high risk of extinction in the wild. It is also listed on Appendix I of CITES.

The range of the Cross River gorilla is restricted to the hilly rain-forest region along the Nigeria-Cameroon border (Oates et al., 2007). Separated from the nearest population of western lowland gorilla to the south by approximately 200 km, the subspecies is scattered across a surface area of approximately 12,000 km² (Oates et al., 2007). About one-third of Cross River gorilla landscape occurs in three areas of Cross River State, Nigeria (the Afi Mountain Wildlife Sanctuary, the Mbe Mountains, and the Okwangwo Division of Cross River National Park). In Cameroon, there are five key areas for Cross River gorillas, all located within Cameroon’s Southwest Region (Takamanda National Park and adjacent Mowambi Hills, Mone River Forest Reserve, the Mbulu-Oko forest, and Bechati-Fossimondi-Besali forest) except the Kagwene Gorilla Sanctuary which extends a few kilometers into the Northwest Region (Bergl et al., in press; Oates et al., 2007). To learn more about the distribution of this subspecies please activate the Gorilla gorilla diehli range layer in the interactive map.

The total population of Cross River gorillas is estimated at 250-300 individuals (Oates et al., 2008). Many of the sites where Cross River gorillas are found contain relatively small numbers of animals, commonly 20-30 individuals, and only two sites (Okwangwo and Takamanda) are estimated to contain larger groups up to a maximum of 50-65 individuals. Large areas of unoccupied potential Cross River gorilla habitat remain, and these provide connectivity between many of the subpopulations (Bergl et al, in press).

While all western gorillas are Critically Endangered, the Cross River gorilla is the most endangered of the African apes. The lack of strictly (and effectively) protected areas throughout much of its range (mainly in Cameroon) makes the future of their habitat uncertain. Little is known about past distribution and abundance but early reports indicate their numbers were higher in the past, and recent genetic analysis suggests that a marked reduction in total population size is relatively recent and attributable to hunting acerbated by increased availability and use of guns (Oates et al., 2007). The Cross River gorilla is a protected species but enforcement of wildlife laws is often poor. Gorilla meat is eaten, and body parts are used for traditional medicine (and on rare occasions live infants are sold for the pet trade). Recent conservation efforts have helped to reduce hunting but the threats remain, and the loss of even a few individuals poses a serious threat to population viability given the small numbers at each locality. This subspecies is at risk due to small numbers and potential for inbreeding, and loss of genetic diversity.

The greatest threat currently facing Cross River gorillas is habitat loss and fragmentation caused by the spread of agriculture, cattle grazing and road construction. Much of the montane forest that probably once harbored gorillas has been lost to agriculture, and at higher altitudes, converted to grassland. Many human settlements surround the margins of the subspecies range and their continuing expansion will likely lead to further fragmentation. Road improvement and development also contribute to habitat loss and fragmentation, as new areas for settlement and cultivation are opened up. Once habitat becomes fragmented it can make migration between different gorilla strongholds difficult if not impossible.

Whilst cases of epidemic disease such as Ebola and anthrax have not yet been recorded among apes in the Cross River region of Cameroon and Nigeria, the risk of disease transmission is high as humans, domesticated animals and apes live in close proximity and use the same habitat. The small size of subpopulations makes them extremely vulnerable as groups could be wiped out by virulent infections (Oates et al., 2007).

Despite being named as a new species in the early part of the twentieth century, the Cross River gorilla was largely neglected until the first systematic surveys began in 1987. Since then it has received increasing attention from scientists and conservationists. This attention revealed fewer than 300 Cross River gorillas in at least 11 discrete localities, approximately 10 km or more apart, spread across an area of 12,000 km² (Oates et al., 2007). Recent genetic studies suggest that gorillas at 10 of these localities constitute one population, divided into three subpopulations that occasionally migrate (Oates et al., 2007).

Three key workshops held to exchange information and to formulate strategies to improve the conservation prospects of the Cross River gorilla took place in 1999, 2001 and 2006. These meetings convened a broad range of experts, decision-makers and stakeholders that agreed a set of priority actions formulated into an IUCN Action Plan (Oates et al. 2007). The recommendations fall into two categories: actions that need to be taken throughout the Cross River gorilla range, and site-specific recommendations.

Substantial progress has been achieved on the various actions and strategies outlined in the 2007 Action Plan including: the development of a landscape approach (given the nature of their distribution) that includes cooperation between relevant decision-makers, practitioners and stakeholders across the Cameroon-Nigeria border; increased awareness-raising across society to the value of conservation generally but also to the uniqueness of Cross River gorillas; greater community participation which necessitates understanding and cooperation between government agencies, NGO’s and local communities; evaluation of gorilla habituation for tourism given the inherent risks; review of existing legislation and support for enforcement of laws; expansion of research including surveys of lesser known areas (particularly within potential corridors), population monitoring, ecology, behaviour and genetic sampling; continued capacity building for research and conservation in government departments, universities, and NGOs; and the development of a management committee for Cross River gorillas in Nigeria and Cameroon was also proposed, but has yet to be established (Oates et al., 2007).

These actions have focused on the 6 protected areas where Cross River gorillas are found: (in Nigeria) Afi Mountain Wildlife Sanctuary, Mbe Mountains Okwangwo Division of Cross River National Park, (in Cameroon) Takamanda National Park, Mone River Forest Reserve and Kagwene Gorilla Sanctuary. Increasingly, the intervening landscape where gorillas are also known to occur has become a strong focus. Efforts to conserve such areas in Cameroon are critical given that as much as 45% of the population there lies outside of established protected areas and local communities are being increasingly encouraged to assist with this process. Across its range, efforts to better understand and plan for maintaining connectivity are also a major current focus.

The survival prospects for Cross River gorillas are promising if they and their habitat can be effectively protected. Large areas of unoccupied potential Cross River gorilla habitat remain; these provide connectivity between many of the subpopulations, and allow for range expansion of various groups if hunting pressure can be reduced. They have managed to persist in places where their survival may have seemed unlikely. Knowledge of the gorillas and local awareness of their importance has increased and conservation efforts have been endorsed by Ministers in charge of wildlife in both range-state countries. There is now a need for Governments, partners and stakeholders to evaluate the progress achieved in implementing the 2007 Action Plan and to outline a renewed set of actions that will further improve the survival prospects of Africa’s most endangered great ape.

There are two species of gorilla, the eastern gorilla (Gorilla beringei) and western gorilla (Gorilla gorilla). The eastern species of gorilla consists of two subspecies, the mountain gorilla (Gorilla beringei beringei) and eastern lowland gorilla or Grauer’s gorilla (Gorilla beringei graueri). The mountain gorilla is classified as Critically Endangered (C1) on the IUCN Red List (Robbins et al., 2008), which means it faces an extremely high risk of extinction in the wild. It is also listed on Appendix I of CITES.

The mountain gorilla is found in two isolated subpopulations, Bwindi Impenetrable National Park, Uganda, and the Virunga Volcanoes region straddling the border between Rwanda (Volcanoes National Park), Uganda (Mgahinga Gorilla National Park), and the Democratic Republic of Congo (Virunga National Park) (Robbins & Williamson, 2008). To learn more about the distribution of this subspecies please activate the Gorilla beringei beringei range layer in the interactive map.

The Virunga mountain gorillas are the best known of all gorilla populations due to the legacy of primatologist Dian Fossey and having been studied since 1967. The most recent survey shows that the Virunga population is increasing, although still very small at 480 individuals and facing many threats (Gray et al. in prep). The Bwindi population appears to be stable at about 300 individuals (Guschanski et al., 2009).

Threats to mountain gorillas include habitat degradation and loss, poaching and disease transmission. Mountain gorillas live surrounded by some of the densest rural human populations in Africa, with a correspondingly high demand for land, food and fuel wood. As a result, these gorillas have been confined to two forest islands (Ferris et al., 2005).

Caught between the 1994 genocide in Rwanda and a civil war in Congo that started in 1996, the Virunga population suffered numerous impacts from more than a decade of conflict and political instability. Refugees and militia put significant pressure on gorillas and their habitats through uncontrolled harvesting of wood for fuel and habitat conversion for cultivation. Gorillas were also caught in the cross fire (Kalpers et al., 2003) or deliberately targeted (Williamson & Fawcett 2008). Groups may disintegrate in response to loss of the dominant silverback, and this can result in additional fatalities.

Whilst mountain gorillas are no longer hunted for meat, they may get caught in snares set for other mammals, which can result in gorilla injury or death (Plumptre & Williamson, 1999), infants are sometimes captured to be sold illegally. Since 2003, 16 eastern gorilla orphans (both Grauers and mountain) have been confiscated (pers., comm., T. Stoinski, DFGFI, May 2011) and many adults have been killed trying to protect their infants.

Threats to the Bwindi population include poaching (gorillas get caught in snares set for antelopes and other small animals), and illegal pit-sawing, collection of fuel wood, habitat destruction and loss, and fires (McNeilage et al. 2006).

On a daily basis approximately 75% of the individuals in the Virunga population are visited by people (tourists, researchers, guides, porters, and rangers) (Williamson & Butynski, in press). A threat common to both populations is the risk of disease. Transmission of infectious diseases has been proven among habituated wild gorillas, people, domestic animals and other wild animals (Williamson & Butyski, in press). Viral respiratory disease of human origin caused the death of two mountain gorillas habituated for tourism in Rwanda (Palacios et al, 2011). Given the use of tourism as a key strategy in gorilla conservation, strict guidelines have been developed to minimize disease risks (Macfie & Williamson, 2010).

Many national, regional and international organisations are working to protect the mountain gorilla and its habitat through conservation and research programmes. Monitoring of the Virunga population since the 1960s and research, on social structures, group dynamics, feeding behaviour, habitat use, and reproduction, not only increased our understanding of gorilla biology but directly contributed to conservation action, raising awareness of the public globally, facilitating political awareness and support, and raising funds (Ferriss et al., 2005). The Impenetrable Forest Conservation Project in Uganda led to the establishment of the Bwindi Impenetrable National Park in 1992 (IUCN, 1996). Research supported the preparation of a management plan for the park, updated in 2001, to guide tourism development, biological inventories, and other measures that are now in place (Ferriss et al., 2005). The presence of researchers and conservationists can have a protective influence on a study population although only if sustained over a long period of time (Campbell et al., 2011), as has been the case of the mountain gorillas.

Mountain gorilla habitat is surrounded by dense human populations with high levels of cultivation and natural resource extraction for fuel wood and shelter. Following the deforestation and cultivation of a large area in the Mikeno sector of Virunga National Park in 2004, one of the initiatives undertaken was to extend the dry stone walls that clearly demarcate the park boundaries. It is hoped the wall will limit cultivation and prevent buffalo from leaving the park and raiding crops in adjacent fields.

The park authorities from all three countries have signed a number of agreements to support transboundary natural resource management and regional collaboration for mountain gorilla conservation. Both Rwanda (2003) and DRC (2005) have developed National Great Ape Survival Plans (NGASPs) which highlight conservation strategies and priorities to safeguard ape populations in the respective countries.

There are enormous pressures on the gorillas and park authorities to meet tourism demand. Exposing gorillas to humans on a regular basis is a risky business and strict protocols are in place to minimize risk that includes maximum number of visitors, maximum time for visitors to spend with gorillas, and minimum distances. Tourism, does however provide an important mechanism to support and value gorillas and their habitat, and has contributed to their survival thus far, with demonstrated direct and indirect conservation benefits. It has led to increased surveillance of habituated groups, more anti-poaching patrols, and facilitates veterinary intervention when necessary, such as removal of snares. It also generates significant revenue (national and locally), increases public awareness, and has certainly been key in securing government commitments to the protection of gorillas and their habitats (Ferriss et al., 2005). The gorilla is a national symbol in Rwanda and DRC, and is depicted on bank notes and stamps. The Rwandese passport and visas for foreigners feature mountain gorillas. Gorillas are also depicted on money in Uganda.

A recent study has shown that habituated groups of Virunga gorillas under extreme conservation measures (e.g., where each group is continuously guarded by a separate team of field staff during daylight hours and receives veterinary treatment for snares, respiratory disease, and other life-threatening conditions) showed an increase in population numbers. This is in contrast to unhabituated groups that received only conventional conservation measures (e.g., law enforcement and community development projects) and whose numbers declined (Robbins et al., 2011). The results suggest that whilst conventional conservation measures can prevent severe declines, more extreme measures are required to allow growth. This finding can help guide conservation planning for this and other highly endangered species, but has serious implications for the enormous resources required for effective conservation.

There are two species of gorilla, the eastern gorilla (Gorilla beringei) and western gorilla (Gorilla gorilla). The eastern species of gorilla consists of two subspecies, Gorilla beringei graueri (Grauer’s gorilla or eastern lowland gorilla) and Gorilla beringei beringei (mountain gorilla). Grauer’s gorilla is classified as Endangered (A4abcd) on the IUCN Red List (2008) which means it faces a very high risk of extinction in the wild (Robbins et al., 2008). It is also listed on Appendix I of CITES.

Grauer’s gorilla occurs only in Eastern DRC and is found in the forests east of the Lualaba River and the Burundi-Rwanda-Uganda border. Grauer’s are thought to inhabit three major regions: The Maiko-Tayna Region, encompassing Maiko National Park, Tayna Nature Reserve and the Kisimba-Ikoba Nature Reserve (this area also encompasses “North Kivu”populations as described in Hall et al., 1998a); the Kahuzi Kasese region (encompassing Kahuzi Biega NP); and the Itombwe Massif. At present there are four large populations (Tayna, Maiko, Kasese‐Kahuzi‐Biega and Itombwe populations) and several small, isolated populations with between 18‐50 individuals remaining (Tshiaberimu, Masisi and Walikale) (Mehlman, 2008). To learn more about the distribution of this subspecies please activate the Gorilla beringei graueri range layer in the interactive map.

As with distribution, our knowledge of Grauer’s gorilla abundance is equally limited. Early surveys (Schaller, 1963) indicated up to 15,000 individuals distributed as several fragmented local populations. Surveys in the 1990’s estimated a range of abundance between 8,660 and 25,499 individuals (Hall et al., 1998b). Access to much of Grauer’s gorilla range is only just becoming possible again due to civil war that engulfed the area from the late 1990’s onwards. Whilst information is limited, field workers concur that the subspecies has suffered a decline in numbers (Ferris et al., 2005; Williamson & Butynski, in press). Local declines have been documented in Nzovu and Itebero (Hart et al., 2007) and local extinctions in the Maiko south region (Nixon, 2010). Assuming the accuracy of early surveys, coupled with more recent information, at least 24% of their occupancy range has disappeared during the last 36 years (Mehlman, 2008). It is possible to state with certainty that Grauer’s gorilla populations are highly fragmented and isolated in distribution. Overall densities are extremely low across their range with high densities only in highly localized subpopulations (pers. comm., S. Nixon, ZSL, May 2011).

Past civil conflict in the region negatively impacted Grauer’s gorillas and their habitat. Soon after the outbreak of fighting in Rwanda in the early 1990’s, about half of Rwanda’s civilian population was displaced and 332,000 refugees fled close to Kahuzi-Biega (Ferris et al., 2005). Soon thereafter, fighting broke out in DRC in 1996 and 1998. Activities of refugees, rebels and armies can place significant pressure on gorillas and their habitats through uncontrolled hunting, harvesting of wood for fuel, habitat conversion for farmland, timber extraction and mining. Over four years, the highland sector of Kahuzi-Biega lost about 50% of its gorilla population (Ferris et al., 2005). Insecurity however kept settlers and miners out of some areas and afforded some protection. The current relative resumption of security will be associated with demographic and economic expansion, and is currently the principal threat to the Grauer’s gorilla.

Habitat loss and fragmentation through agricultural and pastoral expansion is related to the westerly movement of people from high density areas in the east to the forests of the west (Mehlman, 2008). As land is overfarmed and becomes fatigued, and hunting resources depleted, settlers move farther (west) into the forest and sell their land for animal grazing. Growth in human density is also associated with higher levels of gorilla killing, the latter simply due to more people being out there with guns and snares. Traditionally gorillas were hunted for food throughout eastern DRC but today gorilla hunting is opportunistic, and much easier due to widespread availability of automatic weapons. Hunting is often commercially driven to feed mine workers and/or military personnel. Gorillas are also captured for the live trade. Since 2003, 16 orphans (Grauer's and mountain) have been confiscated (pers. comm., T. Stoinski, DFGFI, May 2011) and many adult gorillas have been killed trying to protect their infants.

Human settlement is accelerated in some areas by mining. High demand for coltan, a highly valued metal used in the manufacture of mobile telephones and computer equipment, and abundant in rivers around Kahuzi-Biega, lured people from agriculture into mining camps. A fall in coltan prices however caused many miners to turn to wildlife trafficking or to other mining activities (Mehlman, 2008). Mining for tin (cassiterite) and gold is present throughout Grauer's gorilla range, cassiterite especially in the area between Maiko and Kahuzi‐Biega National, and diamond mining is common in the north, specifically within Maiko National Park. Demand for each mineral fluctuates but there is a continuous demand for one or another. It is both direct (mining techniques) and indirect (human settlements) activities associated with mining that cumulatively have a large negative impact on gorilla populations.

Currently there is no commercial logging in G.b. graueri range, but low-level extractive activities (e.g., charcoal production and wood cutting) are a continuing threat and can be very intensive, even if artisanal in scale. Destruction of high altitude forest is a threat in the East although much of this was lost in the mid 1970’s with remnant populations hunted out alongside deforestation. Deforestation still remains a risk for the few isolated populations which still exist in North Kivu Highlands (Tshiaberimu, Masisi and Pinga). However, even in the lower and less fertile regions (west towards Lulaaba) where deforestation rates are very low, gorillas are massively threatened by hunting for bushmeat and in some cases crop raiding (pers. comm., S. Nixon, ZSL, May 2011). As the country emerges from civil war, new concessions for timber, minerals (mining concessions have already been granted in Itombwe region), and possibly petroleum will pose future conservation challenges (Caldecott & Miles, 2005).

Ebola is linked to the significant decline in numbers of western lowland gorillas (Walsh et al., 2003), but is not known to be present in Grauer’s gorillas. Human-origin viral respiratory disease however is proposed to explain the death of two mountain gorillas that died during a recent respiratory disease outbreak in Rwanda (Palacios et al, 2011). Increased exposure of gorillas to humans or their feces is occurring as more people live in or around the forests, and disease may be carried by park guards, researchers, tourists, tour guides, loggers, hunters, miners, or by local people using nearby roads. Given the use of tourism as a key strategy in gorilla conservation, strict guidelines have been developed to minimize disease risks (Macfie & Williamson, 2010).

Much less is known about Grauer’s gorilla in comparison to the mountain gorilla and is largely attributable to warfare throughout its range. Most subpopulations are found in protected areas, where international NGOs are working with government authorities to support rehabilitation and conservation programmes, e.g., in Kahuzi-Biega NP, Maïko NP, Tayna Nature Reserve and Kisimba-Ikobo Nature Reserve (Robbins et al., 2008). The military and political situation however remains highly unstable, and it is very difficult for conservationists to undertake fieldwork and to fully engage with local communities (Ferris et al., 2005).

In 2005 DRC developed a National Great Ape Survival Plan (NGASP) which highlights conservation strategies and priorities to safeguard apes populations. The majority of strategies are ape generic but specific priority actions for Grauer’s gorilla include: the creation and maintenance of reserves (including Walikale, Tayna, Sarambwe); the creation of a corridor between Kahuzi-Biega NP and Maïko NP; and general strengthening of and additional support for existing programmes in Kahuzi-Biega NP.

Prior to the large influx of miners, conservation recommendations focused on the lowland sector of the Kahuzi-Biega NP and adjacent Kasese region. Maintaining the forest corridor between lowland and montane populations was considered essential to ensure gene flow. This corridor however is now severed and settled by refugees and the recent focus has been on crisis management, damage assessment and limitation (Varty, 2005). With the continuing humanitarian crises the corridor may not be recoverable (pers. comm., S. Nixon, ZSL, May 2011).

Outside of Kahuzi-Biega, the Itombwe forest has been highlighted as an important area of conservation focus (Hall et al., 1998a). Government authorities (ICCN) created the Itombwe Nature Reserve to help protect the remaining yet highly endangered and fragmented Itombwe populations. The Maiko Tayna region has been previously overlooked yet it could support the most significant populations outside of the Kahuzi-Biega NP. Efforts have focused on developing community based reserves in the Tayna and Kisimba Ikoba regions and providing support for conservation activities in Maiko NP. Up-to-date information on the distribution and abundance of G. b. graueri across the range is urgently needed to establish new baselines for monitoring, identify key populations and to direct and prioritize conservation actions (Williamson & Butynski, in press; Robbins et al., 2008). In favour of Grauer’s gorilla, they appear to be highly attached to traditional home ranges which mean resources can be effectively focused (pers. comm., J. Hart, May 2011). Support is needed in areas where protection is already established, but at the same time conservation activities need to be initiated in the more remote and inaccessible sectors of Grauer’s gorilla range (Robbins et al., 2008; Williamson & Butynski, in press).

There are two species of gorilla, the western gorilla (Gorilla gorilla) and the eastern gorilla (Gorilla beringei). The western gorilla consists of two recognized subspecies: the western lowland gorilla (Gorilla gorilla gorilla) and the Cross River gorilla (Gorilla gorilla diehli). The western lowland gorilla is classified as Critically Endangered (A4cde) according to the IUCN (2008) Red List (Walsh et al., 2008) meaning that it is considered to be facing an extremely high risk of extinction in the wild. It is also listed on Appendix I of CITES.

Western lowland gorillas are found in Western Equatorial Africa. They are found throughout the forests of Gabon and the Republic of Congo, the forested southwestern part of the Central African Republic (CAR), southern Cameroon, mainland Equatorial Guinea and the Cabinda province of Angola (Ferriss, 2005). They appear to be most numerous in Marantaceae and swamp forests. To learn more about the distribution of this subspecies please activate the Gorilla gorilla gorilla range layer in the interactive map.

Current estimates of western lowland gorillas are about 150,000, with approximately 70% living in the Northern Republic of Congo and the remaining populations equally divided between Gabon and Cameroon with a tiny proportion in CAR (Wildlife Conservation Society). Their population continues to decline to the threats outlined below (Walsh et al., 2008).

Two main threats to western lowland gorillas are consistent across the western equatorial region: poaching and disease (particularly Ebola haemorrhagic fever). Poaching is hugely exacerbated by the creation of logging roads (which facilitate both entry of poachers and munitions into the forest and the export of bushmeat out of it) (Tutin et al., 2005). Up to the early 2000’s habitat loss had not been a major threat in the region but will soon pose an extremely serious challenge to their survival. However there is now a very recent and large scale push for conversion of forest habitat to oil palm in the Congo Basin, which will remove a large proportion of otherwise reasonable quality habitat.

The killing of gorillas has been reported across their range (Ferriss, 2005). Gorillas are hunted, and also fall victim to snares set in the forest for other mammals such as antelopes. The motives driving gorilla poaching are varied and include: culture, a source of protein, body parts for traditional medicine and trophies, and live infants for the pet trade. Although killing or capturing gorillas is illegal in every range state, laws are often poorly enforced. Hunting of wild animals for subsistence is widespread across Africa and although gorillas are not specifically targeted for meat, hunters will take them if they come across them (Tutin et al., 2005). The impact of this threat is on the rise with expanding human populations, improved access along logging roads mentioned above, and by easy access to modern weaponry.

Logging is one of the greatest indirect threats to apes in the region, especially in concessions surrounding protected areas (Tutin et al., 2005). Bushmeat, including apes, is sold not only to local villagers but also to logging camp workers (and dependants), and transported by logging vehicles to regional towns and major cities. Even low levels of hunting are believed unsustainable for slow-breeding mammals like gorillas. It should be stressed that gorilla meat is not a food security issue; it is extremely rare for any individual villager to eat gorilla meat, as they are so rare, and in addition, large animals are most favoured by the urban markets. Villagers eat the small antelopes and duikers that they catch, and sell the large species. The massive decline in over half of Gabon’s ape population between 1983 and 2000 was attributed partly to hunting, facilitated by the rapid expansion of industrialized logging (Walsh et al., 2003) and partly to Ebola (see below).

The risk of disease transmission between humans and gorillas is also increasing as formerly remote forests are opened up for resource extraction and settlement (Ferriss, 2005; Tutin et al., 2005). A study in Gabon found that none of the human population that shared habitat with apes was vaccinated against contagious diseases that can spread through ape populations with high mortality rates (Tutin et al., 2005). Ebola caused several massive western gorilla die-offs in some of the most remote parts of the species’ range, which are hugely important sites for their conservation (Williamson & Butynski, in press). While the transmission dynamics of Ebola are not well understood, some predict that Ebola epidemics will reach most of the western gorilla’s current range within the next decade (Williamson & Butynski, in press). As the majority of the worlds’ western gorilla population lies just to the east of current Ebola-stricken areas, this would be a complete catastrophe for the species.

Many national, regional and international organisations are working to protect the western lowland gorilla through conservation and research programmes. Although the largest single population of western lowland gorillas lies in four logging concessions in northern Congo (and not in a park) they are all under Forest Stewardship Council (FSC) management. The majority of the rest of the world’s western lowland gorillas are in the National Parks of Congo, Gabon and Cameroon, and protected areas are still being created. Since 2010, two new National Parks have been created specifically for gorillas; the Ntokou-Pikounda NP in Congo, and the Deng Deng NP in Cameroon, and a new one is soon to be gazetted at the edge of the Bateke Plateau forest zone in Congo.

Several western gorilla sites straddle international borders which require cooperation between two or more countries for effective conservation. One such cross border initiative is the Sangha Tri National Landscape that includes southern CAR, northern Congo, and southeast Cameroon. This conservation initiative covers the contiguous Dzanga-Ndoki, Noubalé-Ndoki and Lobéké National Parks, and divides the area into regions in which human activity is managed or restricted, and allows for joint patrols by armed rangers from the three countries (Ferriss, 2005).

Research programmes are natural partners to local conservation initiatives. Long-term studies of western lowland gorillas began at Lopé in Gabon in 1983, and expanded to Mbeli in the Republic of Congo, Bai Hokou in CAR and Loango in Gabon. All have proved helpful in discouraging poaching. There are a few established tourism operations based around sightings of western gorillas in CAR, Congo and Gabon, including very low impact observations from platforms at the edges of the swampy clearings (bais) favoured by the apes and other animals.

In addition to these field efforts, sanctuaries housing orphaned gorillas have been established in Cameroon, Gabon and Congo. These confiscated apes are cared for and used to deliver conservation messages to local populations about the plight of this endangered species and their forest homes. Some success re-introducing a small number of rehabilitated gorillas in Gabon and the Republic of Congo has also been achieved.

The large geographic range of the western lowland gorilla, political will for conservation, and sparse human population in much of this range, means it has fared relatively well, even in non-protected areas (Ferriss, 2005; Tutin et al., 2005). Despite this, the long term survival of western lowland gorillas will require a synergistic approach that includes more effective conservation strategies and enforcement of government policies (Tutin et al., 2005). In 2005 over 70 experts were convened to develop a regional strategy and action plan for the conservation of western lowland gorillas and central chimpanzees Pan troglodytes troglodytes, which are sympatric over most of their range. The result was a regional action plan that identified seven exceptional and five important areas along with priority activities necessary for the ape’s survival (Tutin et al., 2005).

Based on the best available data and knowledge, the experts identified priority areas in western lowland gorilla conservation, based on the size and extent of ape populations: Odzala/Lossi/Pikounda/Ngombe/ Ntokou complex, Republic of Congo; Lac Télé/Likouala complex, Republic of Congo; Sangha Trinational complex, Republic of Congo, Cameroon and CAR; Loango/Moukalaba-Doudou/Gamba complex, Gabon; Dja Conservation complex, Cameroon; Boumba-Bek/Nki complex, Cameroon; and Lopé/Waka complex, Gabon. Protection of these ape populations would guarantee the survival of the majority of apes remaining in the region, and represent a highly effective investment given the protection that would be afforded to other native fauna and flora (Tutin et al., 2005).

Priority actions for specific sites were identified along with overarching knowledge gaps. Priority actions attached to particular sites include: a disease surveillance programme and rapid response structure; bio-monitoring and baseline surveys where appropriate (Ebo/Ndokbou conservation complex, Cameroon; and Maiombe Forest Transboundary Initiative, Republic of Congo and Democratic Republic of Congo were identified as priorities for surveys); capacity building for research skills generally and standardised protocols for bio-monitoring training and implementation; improvement of judicial and law enforcement structures; development and promotion of national and transboundary structures; development and promotion of responsible great ape tourism; establishment and maintenance of basic management infrastructure at a site level; reactivation and maintenance of permanent great ape research areas; establishment of community-based biodiversity enterprises; and public education and awareness programmes (Tutin et al., 2005).

In addition to prioritizing areas and activities, the action plan also identified overarching gaps in knowledge needed to effectively conserve western lowland gorillas. Some of these knowledge gaps have been successfully bridged. Best practice guidelines have been developed for survey and monitoring of great ape populations to improve estimates of ape abundance (Kuhl et al., 2008). The A.P.E.S site has improved accessibility to data by providing a centralized database with geo-referenced ape survey data. Ongoing activities are focused on: large-scale survey and monitoring (establishment of a regional monitoring programme to coordinate surveys and ensure consistency of monitoring methods); capacity building opportunities in ape research, monitoring methods and technical support for national researchers; and more research on Ebola (transmission dynamics and potential control measures, and evaluation of alternative vaccine delivery methods for wild ape populations (Tutin et al., 2005).

Experts believe that implementation of the plan, if successful, would guarantee the survival of the majority of apes remaining in the region. Many other species would benefit along with the endangered Western lowland gorilla. In addition to site-specific and general knowledge gaps, the plan provides a series of immediate response needs and longer-term mitigation strategies for the three main threats consistent across the region (poaching, disease and logging). Crucially anti-poaching, it is argued, should be the foundation upon which all other ape conservation activities rest, as it is the most effective means of protecting apes in western equatorial Africa (Tutin et al., 2005).