Gorilla Reintroduction Programme, Republic of Congo

By: Tony King

Published in: Gorilla Gazette Vol. 18 (2005), pp. 28-31.

 [view pdf version

As far as I know, the last update in the Gorilla Gazette concerning the Projet Protection des Gorilles (PPG) in Congo was by Mark Attwater in 1994. At that time, preparations were still being made to transfer some of the older gorillas at the Brazzaville Gorilla Orphanage to the Lesio-Louna Reserve, an area of undulating grasslands and gallery forest 140 km north of Brazzaville. The transfer of the first group finally occurred in December 1994, and by December 1998 all the gorillas in the care of the project were located in the Lesio-Louna Reserve, the Brazzaville orphanage having been evacuated during the civil war of 1997. During those ten years since the first transfer to Lesio-Louna, the project has evolved greatly; so much so that since September 2004 there are no longer any gorillas living in complete freedom in the Lesio-Louna Reserve. Four young orphans are still in the Lesio-Louna, spending the nights in small wooden dormitories while learning the necessary skills to survive in the forest during the days. Four adult males also remain in the Lesio-Louna, but now in captivity. The remaining fourteen gorillas that were living free in the Lesio-Louna have now been transferred to the adjacent Lefini Reserve, five in January 2003 and nine in September 2004, in what we believe is the final stage in their full re-introduction to the area.

Before considering the Lefini re-introduction program, we should first look at our experiences in the Lesio-Louna Reserve. The two rivers in the reserve, the Lesio and the Louna, and the escarpments along the eastern boundary of the reserve, were considered to be natural barriers to the movements of the released gorillas. This was the case initially, but as the gorillas grew older and more independent, they were able to use overhanging or fallen trees to cross the smaller of the two rivers, the Lesio. They even learnt to use our ferry to cross the river, operated by pulling on the ropes attached to each bank. This meant that the camp was no longer separate from the free-ranging gorillas, and had to be protected with an electric fence. Even this fence proved unreliable, the gorillas learning to test the fence with grass stems to see if it was working, and even if it was, they broke branches to form bridges across it. The first fence was replaced with a higher fence, but still, the more persistent gorillas improvised ways to enter the camp, by jumping from the water tower, or by ambushing staff as they opened the gates.

These raids on the camp, to find easy food, were annoying and disrupted the project work, and also frightened visitors not used to nearly-full-grown gorillas challenging them for their dinner. However, more serious problems arose when adult males were pushed out of the groups as they matured, and began to range further in the reserve in search of other groups. Of course they didn’t find them, but they did prove capable of following the forests up the steep escarpments bordering the reserve, finding themselves in the banana and manioc bonanza of the surrounding villages. Adult male gorillas gorging themselves on the local harvest was obviously going to end in trouble, one way or the other. The local population showed surprising restraint, and the gorillas were returned to the reserve, sometimes being led by project staff using bribes, sometimes being anaesthetised. Inevitably, though, the males that persisted in arriving in the villages had to be caged to prevent serious accidents. In reality, that was each and every one of the males that reached adulthood while in the Lesio-Louna.

After the first two males had been caged, it was clear that the Lesio-Louna was not suitable for the long-term re-introduction of gorillas. The lack of true natural barriers between the released gorillas and human activity, at both the project camp and the surrounding villages, could not be overcome. While the forests of the Lesio-Louna could still be used during the rehabilitation of younger gorilla orphans, the project had to look elsewhere for the final re-introduction site. The south-west sector of the adjacent Lefini Reserve appeared to fulfil the requirements of major natural barriers to gorilla movement, with large rivers on three sides, and an expanse of savannah on the fourth. The rivers on the east and west sides of the area could conceivably be crossed if the gorillas followed them for a considerable distance south, but it was envisaged that the large forest block along the Lefini river forming the northern boundary would keep the gorillas in that area. Even if they did eventually cross the river on the western edge, there were no permanent settlements on the other side.

Following several years of prospecting missions and communication with the Congolese authorities, the first group was finally released in the north-east corner of the south-west Lefini on 18 January 2003. Made up of two black-back males and three adult females, the group thrived in their new territory, remaining together throughout 2003 and ranging in a similar manner to wild gorillas. During the dry season they moved very little, remaining in a small forest patch of 1.34 km² to feed on the abundant low herbaceous vegetation that provides their staple diet while fruit sources are scarce. During the wet season, though, they expanded their range to include nearly 4 km² of forest, moving regularly between forest blocks to profit from the abundant but widely-spread fruit sources.

During 2004 the group continued to expand its range, but the big event of the year was the birth on April 13th of the first baby to a re-introduced gorilla. The birth came as an unexpected surprise to the project staff, as his mother, at 17 years-old, was the oldest female in the project, and had been associated with four different dominant males during her years in the Lesio-Louna without previously becoming pregnant. After the birth, one of the two males in the group became increasingly aggressive to the females, and gradually became independent of the others. The frequency of meetings between the male and the group decreased from May, until at the end of October the solitary male suddenly increased his ranging, exploring the area rapidly in a manner similar to the solitary males in the Lesio-Louna. During November, he explored an area over double the size of the range used by the group during the previous year and a half. By the 25th November, the solitary male had crossed a patch of savannah to reach the northern tip of a forest block known as Abio. If he followed this forest, it would lead him south along the Louna river, on the eastern border of the south-west Lefini. If then he continued to follow the Louna south, he would eventually find the opportunity to cross the Louna river, and arrive back in the Lesio-Louna Reserve. The problems of solitary males appeared to be returning.

However, on the 8th September 2004 we had transferred a group of nine sub-adults and juveniles to the Abio forest, several of whom had spent a considerable amount of time with the solitary male when they had been in the same area in the Lesio-Louna. So when the male followed the Abio southwards, within five days he had met the group, and immediately his travels were over. Upon his arrival, four of the younger members of the group must have fled, as they were not found for several days. The remaining members of the group and the adult male stayed together, with no apparent problems. That was last week, so we await news of the evolution of the situation on a daily basis.

So that has brought you up to date with the gorilla re-introduction programme over the past ten years. We are very pleased with the progress of the gorillas so far released into the south-west Lefini, this year’s birth was arguably the highlight of the project so far. But as I sit here at our simple camp on the opposite side of the Louna river to the gorillas, looking out over the Lefini river, the associated gallery forest, and the impressive red sandstone cliffs topped with green savannah grass behind, I feel that what we are doing here is more than a gorilla re-introduction programme. And I don’t just mean the other programmes that make up the Projet Protection des Gorilles in Congo, primarily the orphan gorilla confiscation and rehabilitation programme and the education and awareness programme. What I’m thinking about is the Lefini ecosystem. When Mark Attwater and others were preparing the transfer of the first group of gorillas from the Brazzaville orphanage to the Lesio-Louna Reserve, they chose the Lesio-Louna partly because there were no wild gorillas or chimpanzees remaining in the region. They were wrong about the efficacy of the Lesio river and the escarpments to act as barriers to gorilla movements, but they were right that the area was beautiful but degraded, basically an ecosystem in need of restoration. The same goes for the Lefini Reserve. A beautiful ecosystem in need of restoration.

In the Lefini, the gorilla re-introduction programme can be considered the cornerstone of a larger Lefini ecosystem restoration programme. The large mammal densities have been reduced by years of over-hunting. If you look at the trends in the sizes of fish you can buy from fishermen as you travel the Lefini River, even the fish appear to be struggling. International conservation organisations have come to Congo and have taken responsibility for several of the reserves elsewhere in the country, those which still support wild populations of gorillas, chimps and elephants. They have come to Lefini, they have surveyed the fauna and the flora, they have studied the socio-economic aspects of the area, they have made proposals for management, they have been impressed by the unique scenery, but they have not secured long-term funding and they have not taken management responsibility. It is an ecosystem in need of restoration, not just protection. And that appears hard to justify to international donors.

Unless, perhaps, those donors have other ideas. The gorilla rehabilitation and re-introduction programmes here in Congo, and in Gabon, are based on the passion for gorillas of the late John Aspinall. Or at least the underlying ideas and the long-term funding are. But there are others who share similar passions. A growing number of gorilla and chimpanzee orphan rescue and rehabilitation projects across Africa are finding, and perhaps competing for, funding and support. They must all be facing similar problems and challenges, and must also be converging on similar solutions. Ecosystem restoration should be one of those solutions. Through exploring possibilities that have been ignored by the traditional conservation organisations, the needs of ape rehabilitation projects could be met while filling the gap in African ecosystem conservation projects, thereby bringing degraded ecosystems back to life. It’s an exciting prospect. And it’s not new (see Ancrenaz 2000). But is it realistic?

Here in the Lefini, what would be different if we considered our programme as ecosystem restoration? How could we restore the Lefini ecosystem? Possibly by a zonal management system which included protection of a certain area to allow large mammals and fish to reverse the decline in population numbers due to unsustainable hunting and fishing? And perhaps by reintroducing the gorilla, a key-stone species, important for the regeneration of the forest, that can not return itself because it has been completely exterminated? Outside of this core protected area, perhaps zones of varied rights of sustainable use by local users? And then working with local community leaders to manage the programme, employing local people, and encouraging tourism to boost the local economy? So yes, you’ve guessed it, that is what we’re doing (although of course the reality is not quite as rosy as the theory). But we’re calling it a gorilla re-introduction programme, not an ecosystem restoration programme. So it wouldn’t change our activities a great deal, but I believe it would change the attitudes of local people, Congolese authorities, and international conservationists (and, why not, donors?).

When people come, local fishermen or visiting diplomats, would a different name help them see what I see? The de Brazza monkeys feeding on the trees opposite the camp, the hippo stretching his jaw muscles in the Lefini river in front of me, the fishermen stopping at our camp to register their permit from the village committee, the fishermen returning to our camp to sell us fish that are bigger than last year (okay, I can’t prove that, but I’m sure it must be true), and an 8-month-old gorilla riding on his mother’s back. Two years ago it wasn’t like that here. Now it is. I believe that is the beginnings of restoration. And I hope the world can see that.


Ancrenaz, M. (2000) H.E.L.P. Habitat Ecologique et Liberté des Primates. Gorilla Gazette 14(1): 28-31.

Attwater, M. (1994) Congo project update. Gorilla Gazette 8(1): 4.