Everywhere in Africa human influence on gorillas and their habitats has become common. Interventions are severe everywhere, not only by deforestation, hunting, mining etc., but more recently also, for example, by the effects of climate change. The human population pressure in the distribution area of eastern gorillas has been extremely high for decades and is still increasing (Plumptre et al. 2003). Mountain gorillas are an extreme case; they live in two forest islands - the Bwindi/Sarambwe forest and the Virunga Conservation Area - separated by about 30 km. As their forest islands are surrounded by agriculture, they have lived close to humans for a long time.

When mountain gorillas initially were studied by researchers, it soon became obvious that the conservation of both the species and their habitats was urgent, therefore strategies were developed and discussed. And as soon as cute mountain gorilla photos were published in the media, it was clear that the gorillas could be used to ensure the conservation of the forests they need for survival. These photos made the apes very popular and many people wanted to meet them. Nowadays, we may get the impression that the protected areas are no longer wilderness. Are the mountain gorillas still wild animals or are they living in a huge safari park?

Habituation and the Consequences

The most serious intervention of researchers is to contact the gorillas closely. Dian Fossey became famous for her impressive photos with mountain gorillas. She started to habituate them in 1967 (Fossey 1983). Habituation means that animals are slowly accustomed to human presence. This practice became a standard procedure for gorilla researchers. However, it became obvious that the habituation process is not only very stressful for the gorillas (Klailova et al. 2020, Shutt et al. 2014) but after its completion it also bears risks for them: poachers can approach them more easily and the gorillas are less afraid of humans in general (which increases human-wildlife conflicts and the risk of disease transmission).

Having been habituated to humans, gorillas can not only be visited by researchers, but also by tourists. In Rwanda the Mountain Gorilla Project (now IGCP) started tourism in 1978, in the Virunga National Park a project of the Frankfurt Zoological Society and WWF started in 1984 and in Bwindi tourism started in 1993. The aim was to increase the income of the national parks and thereby to encourage the authorities to prevent further destruction of the forests in order to protect the gorillas. To keep disturbance as low as possible, the number of visitors, the time spent close to the gorillas etc. were regulated by strict rules. But this was not the first time that tourists could see gorillas; in Uganda, Walter Baumgärtel had already started mountain gorilla tourism in the late 1950s. The first one who habituated gorillas for tourists was Adrian Deschrijver in Kahuzi-Biega, where the first visitors saw the gorillas in 1972 (Butynski & Kalina 1998, Goldsmith 2014).

Among researchers and conservationists, the growing tourism caused many discussions. Like any contact, tourism may be dangerous for the gorillas (disease transmission, increased stress etc., especially if the rules are not observed - which unfortunately happens very often, see Butynski & Kalina 1998, for example). But even critical experts agree that tourism can increase government and public support for gorilla conservation. Mountain gorilla tourism has become an important source of income for the range countries, and they have tried to earn as much profit as possible from it. In the Virunga Conservation Area, the number of habituated gorillas increased dramatically since the start of gorilla tourism; in 2010, more than 70 % of the Virunga gorilla population were habituated (Gray et al. 2013). This is not considered sustainable, for example because an epidemic disease transmitted to the gorillas by humans could put the whole population at risk.

This leads to another intervention that requires habituation: veterinary care. At the request of Dian Fossey, the Mountain Gorilla Veterinary Project (today: Gorilla Doctors) was launched in 1986. Since then, the veterinarians have been caring for the habituated mountain gorillas in the Virunga Conservation Area, later also in other protected areas for eastern gorillas. With their work, a new kind of gorilla management started. Their aim was to intervene mainly when the gorillas suffered from diseases or other medical problems that were caused by humans, for example to remove poachers' snares, treat epidemics, prevent diseases by educating the population, tourists and employees, and to reduce contact of gorillas to humans and domestic animals. Moreover, they conduct research (MGVP/WCS 2008).

Managing Gorilla Populations

Before researchers, conservationists and employees of companies that exploit the forest entered the gorillas' habitat, the local population was the gorillas' contact to humans and also the main threat for them. Occasionally people, especially hunters, were attacked by gorillas and sometimes farmers killed gorillas when they destroyed crops. Thanks to intense conservation efforts, this has now become extremely rare in mountain gorillas.

Any intervention in the gorillas' habitat also has an effect on the gorilla population. Of course, humans originally did not have the intention to "manage" anything when they hunted gorillas or cut the forest for agriculture; this idea started when gorilla conservation became professionalised. Strategic planning meetings were held and action plans were published.

Gorillas usually do not leave their forest, but have done this increasingly since the forests have become more and more fragmented. Mountain gorillas sometimes leave the protected areas to forage in the fields surrounding their habitat. As they like some of the crops and are not afraid of humans when habituated, they do this again and again, which causes human-wildlife conflicts. Crop raiding gorillas are driven back to the protected areas, occasionally they are anesthetised and carried back; unfortunately, the farmers usually receive no or not sufficient refunds for the crops. In the Virunga National Park, Democratic Republic of the Congo, an electric fence was erected in 2020/21 to prevent animals leaving the park to forage in fields (Nakayima 2002).

Despite their very restricted habitat, mountain gorillas are the only ape subspecies with an increasing population size. This is the result of decades of hard work and has been celebrated as a big success. It was the result of various management measures. Conventional measures were law enforcement (including regular patrols by rangers) and community development projects, but additional measures were taken like veterinary care and close monitoring of the habituated gorilla groups. In the Virunga Conservation area, these efforts resulted in a marked increase of the number of habituated gorillas, while the unhabituated ones showed a slight decline (Robbins et al. 2011). Gorilla tourism is also an important factor that helped to save the mountain gorillas from extinction.

However, more recent data showed that the growth of the population in Rwanda has slowed down and stress and aggression have increased; it seems that the gorilla density is already too high there (Caillaud et al. 2020). The forest is becoming too small for the increasing Virunga gorilla population - as a consequence of the management by humans who want to save them from extinction. So further management strategies may be necessary if the population indeed is too large for the limited habitat. An extension of the Volcano National Park has been discussed (very controversially) for several years.

Translocation? As soon as it became clear that isolated small eastern gorilla populations may be threatened, the idea of translocation as a conservation tool came up. In 1975, John MacKinnon suggested transfering some males from Kahuzi-Biega to the Virunga National Park to prevent further inbreeding there - although he was aware that they lived in different habitats and might belong to different subspecies (MacKinnon 1976). Translocation was then discussed in two different scenarios: 1. for small threatened gorilla populations to transfer them completely to another place; 2. for the mountain gorillas to add gorilla groups from other areas to strengthen the population. This was only a theoretical discussion, although a translocation might possibly have saved the last Masisi gorillas (Yamagiwa 1996). There were also serious concerns: the translocated gorillas would have been in a strange environment with strange food plants that they were not adapted to; diseases could be transferred, etc. To transfer a population to a suitable safe area within the Grauer's gorilla distribution area would have been almost impossible. Nobody knows whether translocations of wild gorilla populations are feasible at all; apart from the enormous logistic and financial efforts, the survival of individuals or the whole population could be at risk (for a general discussion see Cowlishaw & Dunbar 2000). At the moment, it is not being considered. Attempts to re-introduce confiscated or orphaned Virunga gorillas to the wild, at least, were have not been successful so far.

Population and Habitat Viability Assessment: After the genocide in Rwanda and the following turmoil in eastern Congo in the 1990s, monitoring of the Virunga population was difficult or even impossible, and experts were very concerned that the gorillas there could become extinct. In 1997, a population and habitat viability assessment workshop for the mountain gorillas was held (Werikhe et al. 1998). The working groups discussed the status of various gorilla conservation aspects and developed recommendations. One question that was discussed during the PHVA was: Should mountain gorillas be expected to "pay" for their conservation? This question is based on the point of view that conservation can only be successful if it generates revenue. For the mountain gorillas (but not for other gorilla populations) the answer is: gorillas are able to "pay" for their conservation because the economic return of tourism is higher than that of other land use like agriculture.

The management of natural resources usually involves many stakeholders who have their own interests. Western conservationists have been accused of wanting to preserve wilderness in Africa, especially attractive wildlife, for presenting them to tourists, but ignoring the needs of the local population. However, community participation has been an important factor in gorilla conservation from the start. Projects for communities are supported to provide alternatives for entering and exploiting the protected areas. Moreover, they encourage the population to cooperate with the management of the protected area. There is a lot of space for improvement, however; each case has to be examined individually (opportunities and problems are discussed in Cowlishaw & Dunbar 2000).

Priority Populations

Among gorilla populations, the mountain gorillas are an exceptional case. Their successful conservation required the investment of enormous resources - and this cannot be simply copied to protect other gorilla populations. In other regions, especially in areas where the gorillas are not habituated, it is impossible to generate funds for the same conservation activities like in the Virungas and in Bwindi. Most protected areas for eastern gorillas are struggling to fund even the most urgent law enforcement measures. Moreover, many people have argued that the needs of wildlife should not be prioritised over that of humans; the growing human population should be given the right to use at least part of the protected areas for their purposes.

It is not easy to decide which gorilla population has the best chances to survive and to direct all available resources to their conservation. Apart from evolutionary uniqueness and extinction risk, the biodiversity of the area and the importance of the habitat are important factors in the discussion (Cowlishaw & Dunbar 2000). John Oates used these criteria to compile a priority list for conserving primate populations. The mountain gorilla populations are ranking very high on these lists (1985).

Mountain gorillas live in the Albertine Rift - a biodiversity hotspot and an extremely important region for several reasons. Within this area, the Virunga Conservation Area and Bwindi also are two of the most important sites for conservation (Plumptre et al. 2003). Moreover, it has become very obvious during the past decades how important it is to save as much of the remaining forests in the Albertine Rift for the climate and for humans. The gorillas as a flagship species may help us to convince more people to support this.

"Wild" gorillas

If we want the gorillas to become "wilder" again, we could reduce the activity of conservationists and tourists in their habitats; but this would mean that the forest and as a result the gorillas could be destroyed. This would have severe consequences. Forests are an extremely important watershed for the surrounding population and their agriculture, and this especially becomes obvious during drought periods. On the other hand, during the rainy season more landslides would destroy villages and fields. The regional climate that already suffers from the global climate change would be affected in a way we are not able to predict exactly.

Mountain gorillas are - at the moment - better protected than other gorillas, and their population is faring well. But they depend on us for their survival. To protect them, it is important to reduce all risks as much as possible, and everybody who comes close to them should be aware that she/he is responsible for their future. Gorillas who are in regular contact with humans, especially the mountain gorillas who are monitored during the whole day, tend to change their behaviour, so habituated gorillas are no longer truly wild gorillas(Butynski & Kalina 1998).

But what about the unhabituated mountain gorillas? Researchers only have indirect evidence of them such as genetic material and hormonal analyses. But they are happy that at least some wild mountain gorillas still range the forests. Tourists will never see them because they vanish as soon as humans approach - and it has to be like that because otherwise they would not stay wild.

Angela Meder

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