The Dja Biosphere Reserve in Cameroon is home to forest elephants, western lowland gorillas and common chimpanzees. The ZSL field team share the challenges they face on a typical day collecting camera traps, which are used to monitor wildlife.
A normal working day for the ZSL field team in the Dja Biosphere Reserve starts just before sunrise. Unfortunately it’s not the dawn chorus that usually wakes you, but the sound of pots being thrown into the nearest water source to be cleaned before the morning meal is prepared.
Dining in the forest can be a monotonous affair, after all, there are only so many mornings you can have fried pasta with tinned sardines. However, the diet is sometimes improved when one of the guides returns to camp having been fishing in a stream with a hand-built rod or extracting some honey from a nearby beehive.
Eventually the whole team, made up of ZSL field staff, a MINFOF Ranger (Ministry of Forestry & Wildlife) and guides and porters belonging to Baka and Bantu (local ethnic groups), will pack the camp down and begin trekking to the next wildlife camera-trap location.
Navigating and moving in the Dja forest is more like an obstacle course than your normal woodland walk, mainly because there are no paths other than those made by wild animals. This means that you need a dedicated ‘machetter’ to follow a compass bearing and open the path with a machete to enable the rest of the team to pass through. This is a thankless task, often resulting in some very tired and scratched arms come the end of the day!
Dense undergrowth is not the only challenge, fallen trees have to be climbed over or scrambled under and large rivers traversed on perilously slippery and narrow logs. Whilst the forest clearings known as ‘bais’ by the locals are favoured locations for elephants and other large mammals, they are exhausting to cross as they often consist of floating grass mats in swamps, with tall, tangled vegetation.
A misplaced step often results in sinking up to your knees in mud and on more than one occasion, someone had to be hauled out by their arms after sinking and getting stuck. It was around these swamps that the team most frequently saw wildlife, such as sitatunga or water chevrotain diving into the undergrowth as soon as we were spotted.
The most distinctive and welcome sounds in the forest are the squawks and whistles of African grey parrots passing overhead or the mocking laugh of a hornbill flying away as we approach. As you progress further into the reserve, the alarm calls and furious rustling of branches by small primates, such as the moustached guenon, punctuate your journey through the habitat.
Despite their large size, forest elephants are surprisingly agile and silent in the forest, pushing through the majority of obstacles in their path; their keen senses allowing them to avoid the team with ease. However, they do leave very obvious signs of their presence - with trees and branches adjacent to ‘elephant highways’ covered in distinctive rub marks, footprints in the ground and large piles of dung.
‘Elephant sign’ was frequently encountered during the trek and the guides became increasingly apprehensive as we discovered fresh sign less than a few hours old. A surprised elephant can be quite dangerous, particularly with the team on foot.
The beep of the GPS signals to the team that we are within 100m of the camera-trap location, causing a burst of activity. The local guides spread out and begin to search for the tell-tale signs of a placed camera-trap. They are looking for good animal paths that the camera was likely placed on and where the vegetation has been cleared from in front of the camera – a necessity to make sure we don’t have thousands of pictures of moving and growing plants!
With any luck, the camera will be attached to the tree where it was deployed 100 days earlier, undisturbed. However, this isn’t always the case with the more intelligent and curious animals, such as forest elephants, often taking a keen interest in these foreign objects in their environment.
In this recent survey, eight cameras were found on the ground broken to pieces, one as far as 150m away in a nearby swamp. With the camera successfully recovered and stored in a backpack, the trek to the next one 2km away can begin. On a good day you can expect to retrieve three cameras; on a rough day it can be as little as one.
The day’s work finally comes to an end at around 4pm when the frantic search for that night’s water source begins. The favoured location is next to a clean flowing river, but all too often the guides would say “c’est la vie dans la foret” when camp was stuck next to a small trickle of water or a stagnant bog as the sun set. At this point, everyone takes the opportunity to rest, have a hot drink before dinner, attempt to dry clothes and talk around the fire before it all begins again the next day.
Camera trapping is very important in dense tropical habitats like the Dja Biosphere Reserve, when even seeing a few red river hogs and duiker over an 18 day trek is considered a satisfactory trip. The combined noise of large groups of people hacking through the undergrowth means it’s a small miracle that any wildlife is seen at all on these expeditions. Animals adapted to living in rainforests are often secretive, cryptic and nocturnal. This means they are rarely encountered during line transect surveys, which is one of the favoured methods of assessing wildlife in tropical forests.
This is where cameras have the edge; they are operational 24 hours a day, discreet and provide undisputable evidence of the persistence of wildlife in these difficult to survey environments. Whilst big animals such as elephant, gorilla and chimpanzee leave very recognisable signs of their presence - dung, footprints and nests - it is the species more sensitive to human disturbance like golden cat, leopard and white-bellied duiker that leave little discernible traces of their activity. These elusive species can provide a good indication of the status of a protected area and therefore camera trapping is a vital surveying technique.
ZSL’s camera traps have detected cat species and other animals that are highly sensitive to disturbance, highlighting the pivotal role the Dja – Cameroon’s largest protected area – has to play in the conservation of biodiversity in the Congo Basin.
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