Leaping between the trees of Sierra Leone’s Gola Rainforest National Park are 12 different species of primates. Studying their lives and the threats they face is no easy task in the depths of a tropical forest. To celebrate World Primate Day, we go behind the scenes to find out what this important work is really like for those undertaking it on the ground. Join Nick Williams, Flyway Conservation Outreach Officer at the RSPB, as he uncovers a story of new technologies blended with old school determination to research and protect Gola’s precious primates.
Getting to know Gola’s primates
“You have to wake up at 4am or 5am … You know it will be difficult to walk during night hours. Sometimes you fall down, sometimes the path gets lost”.
That is how Vandi Lansana, Research Technician at Gola Rainforest Conservation, describes the gruelling business of accessing primate research sites deep within Sierra Leone’s Gola Rainforest National Park. As for the primates themselves, their theme is certainly ‘variety’.
Among the 12 species found in the National Park there are the canopy-dwelling Colobuses and Diana Monkey, as well as forest-floor visitors like the Sooty Mangabey and Western Chimpanzee; a critically endangered subspecies of one of our closest relatives. Venture out at night and you could even find yourself staring into the wide eyes of a Galago, more commonly known as a ‘bushbaby’.
Unfortunately, six of these 12 species are classified as globally threatened with extinction, primarily due to hunting and habitat loss. It is now more important than ever to study their lives and establish which conservation methods used to protect them, alongside the rest of Gola’s fascinating fauna and flora, are proving most effective.
The Diana Monkey is classified as endangered on the IUCN Red List of threatened species. Credit: David Monticelli.
The hard graft
Research work into Gola’s primates is carried out in partnership between Gola Rainforest Conservation and the RSPB. Together with a separate project looking specifically at Chimpanzees, much of the study of the forest’s diurnal primates (those active during the day) focuses on a system of transect lines which are surveyed on a repeated basis. Walking along these transect lines, the research team record all signs of primates and so can build up a picture of their behaviour and estimate the health of their populations.
Some primates are sensitive to forest disturbance, such as Red Colobuses, so they can be useful indicator species by which to estimate the overall health of the forest. They also play a crucial role in maintaining that forest health and structure as they move around the landscape feeding and so dispersing seeds from fruiting trees into new areas.
While the transect theory may sound simple, the reality of gathering this data on the ground definitely isn’t. Some of these transects lie deep within the forest, a full day’s hike from the nearest villages on the edge of the national park. After completing this trek and pitching camp for the night, the team brace themselves for an early start the next morning.
The Western Pied Colobus is sensitive to disturbance and relies on close-canopy forest to move around. Credit: David Monticelli.
Picking their way through the darkness of the forest, the research team navigate by GPS device to reach the start of that day’s transect. This early morning routine is essential to have the best chance of encountering primates as they are most active after dawn but before the heat of the day fully sets in.
Walking along the transect can take up to four hours and the team must stay alert for the sounds of shaking trees or calls by which different species can be identified. It is then important to get a sighting so that identification can be confirmed and other data recorded on behaviour, group size and whether there are infants, as well as the species composition of the group as some of Gola’s different primates will occasionally come together to feed. A laser range finder is also used to help calculate the distance the animals are away from the transect line.
Alongside gathering data on the primates themselves, the team also records signs of human activity they may come across in the forest including any evidence of hunting, mining or logging.
As Mohamed V Sheriff, Senior Research Technician at Gola Rainforest Conservation, describes it: “Most of all, I hate to see signs of poaching while going along the transect. For example, empty shot shells or suspicious trails. It tells me that people are encroaching into the forest and possibly killing the animals”.
Mohammed V Sheriff (left) and Mustapha Dabenie (right), Senior Research Technicians at Gola Rainforest Conservation, surveying the forest for signs of primates. Credit: Ryan Wilkie.
The trouble with transects
The lines which the research team must walk along are designed to give a representative picture of the forest and its varied terrain. Essentially, you can’t plot a transect based on how easy it might be to walk along! So researchers often find themselves scrambling up and down steep slopes or wading through streams, all the while staying on the alert for the sights and sounds of primates.
The transect model also has its drawbacks scientifically. For example, researchers can only stay in one place along their routes for a brief period so the opportunity to collect data is more limited than with some other methods. The very presence of researchers in the forest can also cause disturbance and so may influence the behaviour and abundance of those species that could be encountered. To combat these challenges, the team have been busy exploring other complementary research methods to add to the existing transect surveys and give an even more detailed insight into the lives of Gola’s primates.
Adding tools to the toolbox
Unlike humans walking through the forest, camera traps can remain in one place for weeks or even months on end. Triggered by motion, they are constantly ready to capture images of forest wildlife both day and night. However, as camera traps are usually most effective when positioned near the forest floor (often at the base of a tree), they are generally only able to collect data on species that visit the ground more regularly such as Campbell’s Monkey or Sooty Mangabey.
Edward Kamara, Research Assistant at Gola Rainforest Conservation, setting up an audio recorder called an ‘audiomoth’. Credit: Ryan Wilkie.
So the team have been trialling the use of audio recorders which can capture data continuously in the forest for days at a time and, crucially, can pick up forest sounds and calls from high up in the canopy. Their recordings are then analysed to build up a picture of how Gola’s primates use the forest and which species are more active at different times of day. However, some of Gola’s primates are much more vocal than others so the team are also exploring another complementary research method which doesn’t need sights or sounds to identify species. By analysing water samples from Gola’s streams and rivers, it is actually possible to detect traces of DNA from a range of species – this is known as environmental DNA or eDNA. Early trials have already seen the team record the presence of a variety of primates using the method, including the Galago and Potto, both of which are nocturnal and so are not detected in the transect survey work.
You can find out more about the Gola team’s use of innovative research methods here.
Camera trap images can give us fascinating insights into the secret lives of ground-visiting primates like the Sooty Mangabey and Western Chimpanzee. Credit: GRC-LG.
The bigger picture
The protection of the Gola Rainforest National Park is primarily funded through a REDD+ project, the first such project anywhere in West Africa, which generates income for conservation through the sale of carbon credits. By demonstrating that the project not only delivers important benefits for climate (by protecting the rainforest’s trees) but also conserves wildlife and supports local community development, Gola carbon credits can fetch a premium price.
So these primate surveys form an important part of a much wider piece of work to demonstrate that biodiversity is being effectively protected under the REDD+ project. Alongside this, it is crucial to understand the effect of conservation efforts on primates, such as law enforcement patrols and awareness-raising campaigns as well as the impacts from threats such as hunting. The different surveys used allow conservationists to establish patterns of change for individual primate species and so better inform their protection.
To find out more about some of the wider benefits brought by the Gola REDD+ project in Sierra Leone visit our Conservation Action blog here.
Gola’s primates, including the Western Red Colobus, can give researchers important insights into how areas of the forest are affected by change. Credit: David Monticelli.
The role of primates as indicators of forest health is crucial here. A healthy diversity of primate species indicates that the Gola Rainforest National Park is recovering well from a time in the past when it was designated not for nature protection, as it is today, but for timber extraction. Thanks to the ongoing hard work and dedication of staff and volunteers on the ground, we are continuing to discover more about Gola’s fascinating primates and how we can best protect them in the years to come.
Research work into Gola’s primates is carried out in partnership between Gola Rainforest Conservation (GRC-LG) and the RSPB. Gola Rainforest Conservation is formed by the partnership of the Government of Sierra Leone, the Conservation Society of Sierra Leone (CSSL), the Royal Society for the Protection of Birds (RSPB), and the people of the seven Gola Chiefdoms.
Our eDNA work in Gola is made possible thanks to funding from Basel Zoo. Audiomoth recorders used in our bioacoustics monitoring were purchased with support from Fondation Prince Albert II de Monaco.