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Without data, fate of great apes unknown

Improving the evidence base for African great ape conservation: An interview with Sandra Tranquilli.

Silverback gorilla in Bwindi Impenetrable National Park, Uganda. Photo by: Rhett A. Butler.
Silverback gorilla in Bwindi Impenetrable National Park, Uganda. Photo by: Rhett A. Butler.

Our closest nonhuman relatives, the great apes, are in mortal danger. Every one of the six great ape species is endangered, and without more effective conservation measures, they may be extinct in the wild within a human generation.

The four African great ape species (bonobos, chimpanzees and two species of gorilla) inhabit a broad swath of land across the middle of Africa, and two species of orangutans live in rainforests on the islands of Borneo and Sumatra in Southeast Asia.

Chimpanzees, which once inhabited an area covering 25 countries, are still the most numerous of the African great apes, but they are now extinct or nearly extinct in many countries and local areas. Due to a lack of survey data, estimates of total remaining numbers of the four chimpanzee subspecies vary widely, from 173,000 to 300,000 individuals. Bonobos, which are considered humanity’s closest living relative, may be the rarest of the great apes. They are found only under the arc of the Congo River in one country, the Democratic Republic of Congo (DRC). Bonobo numbers are known to have declined precipitously over the last 30 years, but due to a lack of survey data, population estimates range from 60,000 to fewer than 5,000 individuals. Western and eastern gorillas occupy two regions separated by 900 kilometers of Congo Basin rainforest. The western species may number 100,000 individuals, mostly western lowland gorilla. Eastern gorilla numbers are unclear due to lack of data and impacts of the conflict in eastern DRC, but are definitely fewer than 17,000 individuals.

Sandra Tranquilli. Photo courtesy of Sandra Tranquilli.
Sandra Tranquilli. Photo courtesy of Sandra Tranquilli.

Threats to great apes are legion. Habitat degradation and destruction due to industrial and artisanal logging and commercial agriculture is a major threat, as is commercial bushmeat hunting around logging or mining camps, which may be deep in the forest. As growing human populations expand deeper into forests, habitat destruction from slash-and-burn agriculture as well as conflict with farmers, e.g., when apes raid crops, also threaten ape survival. Ebola virus, which kills both humans and apes, has decimated populations of western lowland gorillas in Gabon and Republic of Congo, and in general, apes are susceptible to many of the same diseases that afflict humans.

In some places, people living in ape habitat have traditional cultural or religious taboos that proscribe hunting or eating great apes. Unfortunately, this “folk conservation ethic” is rapidly waning, especially among younger people. However, some conservationists try to integrate such traditional belief systems with modern ecological science to promote a conservation ethic among local people. For example, because of the physical and behavioral similarities of bonobos with humans, the Bongando people in Wamba and Kokolopori, DRC, have traditional taboos against eating bonobos. The Bongando consider bonobos not as animals, but as “missed” or almost-humans. In Cameroon, in the Cross River gorilla habitat, some people don’t hunt or eat gorillas for fear of harming people who use the animals as their totems, but this practice is eroding as local societies modernize. In northern DRC, the Barisi people in the Uele region have a traditional taboo against eating chimpanzee meat because they consider themselves descended from a marriage between humans and chimpanzees, but this has not protected the apes from hunting by illegal gold miners, who are usually outsiders.

The Max Planck Institute of Evolutionary Anthropology ( in Leipzig, Germany, is a unique institution dedicated to studying primatology and human evolution using fossil, genetic, linguistic, cognitive, social and other evidence. Established in 1997, the Max Planck Institute has rapidly become one of the world’s top institutions for studying human origins.

Since 2005, the institute has hosted the IUCN/SSC A.P.E.S. (Ape Populations, Environment and Surveys) database, an online portal developed to centralize data on great ape abundance, distribution and conservation activities. Ape conservation strategies have in the past often not been scientifically tested or successful, as the continued decline of ape populations demonstrates. The purpose of the A.P.E.S. database is to make survey and conservation information universally available to researchers and conservationists in order to improve great ape conservation strategies, reveal sampling gaps, increase conservation cost-effectiveness, and raise awareness of the need for more funding for conservation programs.

Sandra Tranquilli is the senior author of a December 2011 Conservation Letters paper, “Lack of conservation effort rapidly increases African great ape extinction risk.” Tranquilli and her 41 coauthors collaborated to collect and analyze survey and conservation data on 109 resource management areas (RMAs) across Africa (see map) where great apes were present in 1990. By comparing ape presence/absence in 1990 and 2009, they could assess which conservation activities were most clearly associated with survival of great ape populations. Tranquilli is a PhD student in the Department of Primatology at the Max Planck Institute of Evolutionary Anthropology in Leipzig.


Baby gorilla in Loango National Park in Gabon. Photo by: Rhett A. Butler.
Baby gorilla in Loango National Park in Gabon. Photo by: Rhett A. Butler.

Mongabay: What inspired your work on great ape conservation?

Sandra Tranquilli: I have been interested in animal behavior and ecology since I was a small child. I was fascinated by observing insects, birds and small mammals that lived in my parents’ garden in Nespolo, a beautiful village in the mountains in Italy, and I constantly scared my family by bringing home animals or skulls or other treasures. When I was 11 or so, I brought home a bat with a broken wing and hid it in my bedroom so I could study it later. That night my mother was looking for me and when I didn’t answer the door, she went into my room—and the bat got scared and flew right into my mother’s hair! Both of them were terrified, and the more my mother shook her hair to get the bat out, the more entangled it became. After that I tried to bring home fewer flying animals!

When I finally travelled to tropical Africa for my undergraduate study, I was shocked to see first hand the bushmeat markets and the deforestation from logging and fires (to clear fields). I decided I wanted to do something to protect endangered species and preserve their natural habitat, and to call attention to these pressing issues. Great apes are one of the most endangered species in Africa and need urgent protection.

Mongabay: You and your colleagues collected and analyzed 20 years worth of data on presence/absence of chimpanzees, bonobos and gorillas in 109 resource management areas (RMAs) in 16 African countries in order to determine the impacts of conservation activities (specifically, law enforcement, research, tourism and NGO support) on great ape survival. Was this the first study of its kind, which assessed the effectiveness of conservation efforts across the entire African great ape range?

Guards on patrol in Kahuzi-Biéga National Park in the DRC. Photo by: A. Plumptre/Wildlife Conservation Society.
Guards on patrol in Kahuzi-Biéga National Park in the DRC. Photo by: A. Plumptre/Wildlife Conservation Society.

Sandra Tranquilli: Yes, the study, which looked at the benefits of great ape conservation on a continental scale, is the first of its kind. It is also a collaboration of all the players involved, both practical (on site) conservationists and scientists. I believe that together we can devise better conservation approaches. Our work is a first attempt at evidence-based conservation, by identifying which conservation approaches have failed or succeeded over a long period of time.

Mongabay: Your report states that RMAs across Africa are often “poorly managed and weakly protected.” Please define “resource management areas.” How are these different from protected areas?

Sandra Tranquilli: Resource management areas are areas established for the purpose of protecting and conserving natural resources including wildlife, timber and water resources. The term “protected area” is often used, but it is quite misleading because many are “paper parks”. They are protected on paper but are left alone with no protection on the ground. Establishment of a protected area is, by itself, not enough. Many factors account for the lack of protection: funding is one, and country political and socio-economic instability, corruption, poor environmental protection policies, or poor will to enforce existing laws. In our analysis, we included RMAs with different proportions of years with conservation activities (high, low and absent.)

Mongabay: Can you describe your findings in a nutshell? What are the most effective strategies for saving African great apes in the wild?

Sandra Tranquilli: The bottom line is that the most effective strategy is the long-term presence of conservation activities on site. The longer these are present, the higher are the chances for great apes to survive in the area. In particular, we considered four main conservation activities: first, law enforcement guards, considered primary activities on the ground, tourism and research as secondary activities whose actions are indirect but supportive, and local and international NGO support. We found that they are all extremely important for ape preservation, but when we evaluated their relative importance, we confirmed that the presence of guards is the most effective activity.

Mongabay: One of the strengths of the study is its objective evidence base. Are there other such studies about the effectiveness (or lack thereof) of biodiversity conservation strategies?

Training how to census gorilla nests. Photo by: A. Plumptre/Wildlife Conservation Society.
Training how to census gorilla nests. Photo by: A. Plumptre/Wildlife Conservation Society.

Sandra Tranquilli: An evidence-based approach has never been used to evaluate the effectiveness of great ape protection on a large scale. It has been used on a local scale and for other tropical wildlife species. For example, Genevieve Campbell and her colleagues showed that long-term research sites in Cote d’Ivoire functioned as wildlife refugia by reducing hunting and human activities. However, more studies using this approach are needed.

Mongabay: At the end of the article, you say that more evidence is needed to determine the best specific law enforcement and conservation factors. I gather that data were lacking for most of the RMAs to break law enforcement strategies down into factors like level of training, salary, numbers of guards, resources and equipment, etc. Is this something that could be analyzed on a subset of RMAs? After all, since great ape populations are declining so fast, we don’t have the luxury to wait 20 more years for answers.

Sandra Tranquilli: Indeed we don’t have this luxury, and we are currently looking at the issue. More precisely concerning law enforcement guards, we know from past studies that effectiveness depends on their numbers, equipment, salaries and other resources. One would guess, for instance that guards may be more effective if there are a large number of them patrolling an area. Unfortunately, we didn’t have enough data at the time of the study to look at this. Meanwhile, however, we managed to collect these data and hope to evaluate which factors are most important. We may be even able to perform this analysis on a large scale. So stay tuned!

Mongabay: What about NGO support for conservation? Can you speculate what makes NGO support most effective? Is it all about money, or what other factors are important?

Sandra Tranquilli: It is hard to say, because different NGOs work on different types of conservation programs. NGOs are often involved in several conservation projects at a time—some may focus more on ape conservation, some on other endangered species or natural resources, etc. Some NGO projects relate to conservation education, aid for law enforcement activities, support for the socioeconomic needs of local people, or research. Different programs may need different kinds of resources, including money, knowledge of the problems, international, national and local support, etc. We are not looking into this yet.

Mongabay: How do funding levels differ between international and national NGOs? I assume international NGOs are better funded than national ones?

Tranquilli with chimpanzee tools. Photo courtesy of Sandra Tranquilli.
Tranquilli with chimpanzee tools. Photo courtesy of Sandra Tranquilli.

Sandra Tranquilli: This is an interesting question, but we didn’t analyze this. It can be expected that international NGOs have more funding, more support from external donors, and better access to media. But in both cases, I would expect conservation effectiveness to depend mostly on how long and how constantly they have been active in the field. Other factors may be relevant but are difficult to assess rigorously.

Mongabay: You found that high human population densities and national economic development had negative effects on ape persistence, but that these were less important determinants of ape persistence than conservation effort. This seems to imply that if people care enough, great ape populations can in principle survive economic development.

Sandra Tranquilli: Apes are still surviving in developed areas, but are under very high threat. Both increases in human population density and GDP have negative impacts on ape survival. Development brings infrastructure, creating deforestation, roads, more access for hunters to the forest, and so forth. It is already difficult to make people care about conservation at the level of local communities, but it is even more difficult at a country level. So with more people and more development in great ape habitat, conservation efforts become that much more important.

Mongabay: Foreign conservationists have been accused by people in range states of caring more about animals than people. What are your thoughts on balancing ape conservation with human needs?

Sandra Tranquilli: It is extremely important to balance wildlife conservation and local population needs. We should abandon the idea that conservationists don’t care about the needs of local people. After all, unsustainable use of natural resources damages first and foremost the livelihoods and future of local communities.

Many studies have been published on the importance of balancing local needs and wildlife conservation, and in recent years, more and more NGOs are taking the needs of local people into account—as well as how local needs influence conservation success in an area. More efforts in this direction are needed. I think recognition of the interrelationship between conservation and local development needs should be mandatory for anyone who wants to work in conservation. In general, the key issue is to devise sustainable development strategies, where the very concept of sustainability includes conservation of both animal and other natural resources. Local involvement and local leadership in conservation are also important, as are conservation education programs focusing on the sustainable use of natural extractive resources.

In the specific case of great apes, they are so critically endangered that any hunting of individuals or destruction of habitats may lead to quick extinction. This is an example of unsustainable use of resources. Moreover, it must be said that in many cases ape hunting is not a human need at all, in fact, ape meat is just looked on as a food delicacy, and ape-based objects are attractive souvenirs for rich tourists and the local upper class.

Mongabay: How dependent are African governments on western donors for funding great ape conservation? Do you feel that current donor funding is adequate?

The distribution of the 109 RMAs that were
selected for this study and the 'potential' great ape geographical ranges..
The distribution of the 109 RMAs that were
selected for this study and the ‘potential’ great ape geographical ranges.

Sandra Tranquilli: We didn’t look in detail into these questions. Still, we believe that funding for conservation is not adequate. On the one hand, we need to invest more, and on the other hand, we need to maximize the effectiveness of available financial resources for conservation. For example, as shown in this paper, law enforcement would be the most effective activity in which to invest.

Mongabay: Great ape populations seem to be in crisis everywhere, and it has been said that they may be extinct in the wild within a generation. It would not speak well of humanity if we let our closest nonhuman relatives go extinct. Insofar as lack of international funding is an issue, are there any efforts underway to increase funding for great ape conservation?

Sandra Tranquilli: Both researchers and conservationists are trying to increase the awareness of governments, donors and the general public about the great apes’ critical situation, hoping this will lead to increased funding. Research work like our own will also help in highlighting more and less effective conservation strategies. We strongly encourage researchers and conservationists to contribute data to the A.P.E.S. database in order to identify sampling gaps, carry out further studies, and contribute to evidence-based approaches to conservation.

Mongabay: What can Mongabay’s readers do to help?

Sandra Tranquilli: They can help support great ape conservation and research through advocacy, funding or direct involvement. Great apes need our help now if they are to survive in the wild!

CITATION: Tranquilli, S., et al., Lack of conservation effort rapidly increases African great ape extinction risk. Conservation Letters, Volume 5, Issue 1, pages 48–55. January 2012.

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