Scientific research in the Gola Rainforest of Sierra Leone and Liberia takes many fascinating forms. To celebrate World Rainforest Day, we will be exploring some of the innovative research methods that the RSPB are trialling, together with our partners, to better understand this remarkable part of West Africa. Nick Williams, Flyway Conservation Outreach Officer, picks up the story.
A hornbill calls sorrowfully as it cruises over the canopy. The insect buzz is beginning to rise. Humidity is through the roof. This is the Gola Rainforest; a global biodiversity hotspot in tropical West Africa that straddles the border of Sierra Leone and Liberia. The RSPB has been working with local partners here to help protect the rainforest for over 30 years. Yet emerging technologies are proving that there are still new ways of learning about this remarkable forest and how we can best protect it.
Science that matters
To effectively conserve Gola’s wealth of plant and animal life, from towering Baku trees (Tieghemella heckelii) to secretive Pygmy Hippos and Western Chimpanzees, it is important to understand how these species are impacted by changes in the landscape around them. With clear evidence from research and monitoring work, conservation strategies can be adapted effectively to ensure that these forests are protected for posterity.
Traditional methods of gathering this all-important data, like walking transects to record species observed, conducting point counts of birds, and camera trapping, have given us an extensive bank of data. More recently, the RSPB and our partners have been adding innovative research tools into this mix to complement the existing methods and give a whole new perspective on the forest’s wildlife.
A camera trap being set up in Gola Rainforest National Park, Sierra Leone. Credit: Ryan Wilkie.
GRC research volunteer Edward Kamara setting up an audio recorder called an ‘audiomoth’, in Gola Rainforest National Park. Credit: Ryan Wilkie.
Ears in the forest
The use of camera traps, which are triggered by motion to record pictures or short video clips, has been providing important insights into the secret lives of many of Gola’s more elusive species for several years now. There are huge advantages to them; they do their monitoring remotely so there is less chance of an animal being disturbed by human presence, their positions are repeatable so you can build up a picture of species’ movements over time, and they are constantly ready to record, day or night. They are our eyes in the forest.
Which begs the question: what about our ears? To complement these camera traps, the Gola research team are developing their use of bioacoustics – listening to the forest to understand patterns and changes in the landscape. Audio recorder units are placed at strategic locations and can then record continuously this method of monitoring is done remotely meaning there is less disturbance to wildlife and so an increased chance of detecting threatened species of monkeys and birds. Another advantage these devices have is that, unlike humans walking transects, they can work just as effectively at night and so record nocturnal species like Rufous Fishing Owls, fruit bats, and many amphibians.
These audio recordings can then be analysed (using software driven by machine-learning to identify particular sounds) both for individual species calls and at a whole soundscape level. This second, overview level can show us how the sheer mass of sound, the volume of the forest, as well as the frequency ranges used, changes during the day as certain groups of species become more vocal.
GRC Research Supervisor Solomon M Tommy (left) and GRC volunteer Edward Kamara (right) setting up audio recorder and camera trap units together to help monitor forest wildlife. Credit: Ryan Wilkie.
The audio recorders can also be set up alongside camera traps, and their data overlaid together, allowing researchers to build up a much richer picture of animal activity at a given site. They can also gather information from a much wider area – the view of a camera trap is usually restricted to around 5-10 metres but audio recorders can pick up sounds that have travelled from much further away.
All of this data can then be compared across multiple locations within protected, primary forest as well as with other areas such as secondary forest and agricultural land. In so doing we can begin to understand patterns over time and space to help give us greater insight on how well the forest’s protection is performing and how that compares with changes in other areas.
Water courses in the Gola Rainforest offer researchers important insights through eDNA sampling. Credit: Michael Duff (rspb-images.com).
DNA detectives
Traditional monitoring of forest wildlife often relies on a researcher physically seeing or hearing an animal or possibly recording visible signs of their presence; from piles of dung to marks on trees. However, one new method is allowing the Gola research team to detect the presence of species from invisible traces they leave within a landscape. This is the wonder of environmental DNA.
Environmental DNA (or eDNA for short) can be gathered in many different ways but the Gola team focuses on water courses. Animals living in the forest naturally shed samples of their DNA into its river systems, for example when they come to streams to drink, wade or swim through the water, or through their faeces.
Vandi Lansana, GRC Research Technician, collecting and preserving water samples for eDNA analysis. Credit: Ryan Wilkie.
Monitoring using eDNA can help detect elusive species, like the endangered Pygmy Hippo. Credit: GRC-LG.
To find out which species are present in an area, small samples of water are taken at streams and rivers within the forest and these are pushed through a filter which traps traces of genetic material. The filter is then analysed in a lab and the DNA samples detected are compared with a library of known species and genera to help researchers identify which species were recently using a given area of the forest. As this database grows over time, a long-term picture can be built up to reveal the health of river systems across the landscape and match this to potential impacts on local communities including possible changes in water quality.
Interestingly, while pilot studies have picked up signs of various primates effectively, the method cannot be used to detect the presence of Gola’s endangered Western Chimpanzees in an area because their DNA is simply too similar to humans to be clearly distinguishable. However, this method of monitoring is particularly effective for certain groups of species, like fish, small mammals and one of Gola’s most iconic endangered animals – the Pygmy Hippo, which can otherwise be hard to gather data on.
And that is how just a few drops of water can help us better understand, and so protect, many of Gola’s most elusive creatures.
A group of rangers on patrol capture data using the phone-based SMART monitoring system. Credit: Ryan Wilkie
Signs of illegal human activity in the forest, like this discarded shotgun cartridge, can be more effectively recorded using SMART monitoring. Credit: C Thomas
Staying SMART
When trying to gather information about the health of a rainforest, a key source of information are the people who patrol and protect it – the rangers. When it comes to law enforcement, having boots on the ground is vital. In both Sierra Leone and Liberia, rangers and eco-guards conduct extensive trips into the forest’s interior looking for signs of illegal activity such as bushmeat hunting or artisanal mining. Along the way they also regularly spot signs of forest wildlife. Now, by using a cutting-edge smartphone-based system known as SMART (Spatial Monitoring and Reporting Tool), this information can be recorded and collated in near-real time, making it much easier for rangers to quickly make decisions and efficiently plan their patrols.
With the system rolled out in both Sierra Leone and Liberia, data is now being gathered more effectively across the Greater Gola Landscape. This not only allows rangers to target their efforts as hotspots of illegal human activity emerge, but also provides a long-term dataset on threats facing the forest. This data can then be compared with other information on forest wildlife to help researchers understand which conservation strategies are proving to be most effective and why. It is this use of innovative and complementary methods that is allowing the Gola research team to uncover more and more vital information about this magnificent tropical forest.
Acknowledgments
The RSPB's research work in Sierra Leone is undertaken in partnership with Gola Rainforest Conservation. Gola Rainforest Conservation (GRC-LG) is formed as a partnership between the Government of Sierra Leone, the the Royal Society for the Protection of Birds (RSPB), and the people of the seven Gola Chiefdoms.
In Liberia, our research work is undertaken through our partnership with Society for the Conservation of Nature of Liberia (SCNL).
The eDNA work discussed in this article is part of a project focused on Pygmy Hippo research and was made possible by funding received from Basel Zoo. Audiomoth recorders used in our bioacoustics monitoring were purchased with support from Fondation Prince Albert II de Monaco.
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