Do you ever wonder how many mountain gorillas exist in East Africa? Well, like the next person, you are probably unaware of how many of these very valuable tourist attractions there are, and how they are counted.
Every five years, a census of gorillas is carried out in the Virunga Mastiff – which is a combination of Virunga National Park in DR Congo, Volcanoes National Park in Rwanda and Mgahinga Gorilla National Park in Uganda.
The 2015/2016 mountain gorilla census is being conducted under the framework of the Greater Virunga Transboundary Collaboration (GVTC), with the work being done by Uganda Wildlife Authority (UWA), Rwanda Development Board (RDB), and I’Institut Congolais pour la Conservation de la Nature.
The last census was carried out in 2010, giving an estimate of 480 gorillas living in social groups and 14 long-haired silverbacks (solitary male gorillas). Another census, carried out in 2011, in Bwindi Impenetrable National Park, estimated there were 400 gorillas and 16 silverbacks.
Belise Kariza, chief tourism officer with RDB, says the first round of the census that began in October 2015 was a success.
“The second phase will be mainly about strengthening the accuracy of the first phase, getting the demographics which include age and sex ration, the size and numbers of groups, and the surrounding vegetation and water sources in comparison with the human activity in the area.”
In the previous census, the numbers were arrived at by estimates but the 2015/2016 census is being carried out using advanced technology and DNA samples.
“The census results, which will be released in 2017, are a best indicator of the dividends in terms of security, research and environmental health dividends obtained by the three countries through the GVTC,” says Dr Muamba Tshibasu Georges, executive secretary, GVTC, adding that due to the collaboration, security in the Virunga Masiff has increased, leading to a normal reproduction rate of the gorillas.
A healthy gorilla population is also the result of collaborations between governments and NGOs. Jossy Muhangi, the public relations manager, UWA, says, “Gorilla doctors have researched on the diseases that affect both humans and gorillas and are coming up with vaccines for the people who interact with the animals.”
Last week, the Uganda Cabinet also approved the Uganda Wildlife Bill 2015 that offers stiffer penalties for wildlife crimes in terms of fines and jail terms.
Conservation efforts by the GVTC also include establishing schools and water sources in communities around the Virunga Mastiff to do more towards conservation efforts.
How the census is done
Joseph Arinaitwe, a UWA ecological monitoring and research ranger in Bwindi Impenetrable National Park, says that number of gorillas in the Virunga Massif is now estimated to be at 480.
A new group of data entrants, currently on training, entered the forests on April 4, 2016.
“The census is generally a sweep from one side of the forest to another,” says Arinaitwe, adding, “We are starting on the southern part of the Massif, in Rwanda, and we will end on the Ugandan side. There will be different teams in the forest, in constant communication with each other.”
The census begins with the individuals following a gorilla trail until they locate a nest site. Every evening, gorillas make nests in which to sleep. They never return to those nests.
“Even if they return to the same site, they will make a new nest next to the old one. Each nest contains one gorilla and we consider it used when we find gorilla dung in it.”
The first duty after finding a gorilla nest site is to establish how old it is. If it is older than five days, then it is useless because most of the DNA is gone.
“One site can have many nests, so we label each nest with a small piece of paper. Then, we wear protective gloves and begin establishing the size of the dung.”
Depending on the size of dung found, the data collectors can conclude, using age classification strata, whether an adult male, medium range or baby gorilla was in the nest.
“Dung measuring 7.2cm, with silvery hair in it, means an adult male gorilla (silverback) slept in the nest. Other dung is classified as medium size, though not specifying the sex.”
While measuring the dung, the sample collector has to ensure that his gloves do not touch it because that particular DNA can be transferred to other dung, thus making it hard for the laboratory to have conclusive findings. Also, sample collectors are not allowed to speak while handling the dung because their saliva can mix with the gorilla’s DNA.
After measuring the dung, a sample of it is placed in a tube containing ethanol. The tube is then transferred to a Ziploc bag.
“Ethanol preserves the dung for an average of 24-30 hours before we shift it to another sample tube containing silica to keep it dry. The laboratory analysis to establish the individual DNA of the gorillas is done in a lab in Germany.”
After collecting data samples from one gorilla site, the team follows the gorilla trail to look for more nesting sites.
“From at least three consecutive nest sites, you can tell the average number of gorillas in that particular group. If the first site had 19 nests, the second one might have slightly less or more and this is important because what you missed in the previous site can be found in the next site.”
Once a good number of samples have been collected, it is shipped out of the forest for storage until the end of the exercise when the samples will be transferred to the Germany.
Trekking into Mgahinga forest
It is a cold morning as six teams stand at the foot of Mt Mgahinga, in the Volcanoes National Park, in Musanze, northern Rwanda, listening to the final briefing from their trainers, Anne-Marie Celline, a PhD student and researcher with Maxplank Institute for Evolutionary Anthropology; and Dr Jena Hickey a conservation scientist with International Gorilla Conservation Programme (IGCP).
Each team has two trackers whose duty it is to search for the gorilla trails. I am in Team 7 which is headed by Joseph Arinaitwe.
At 9am, in boots and rain coats, we set off for the edge of the forest. It is a strenuous climb up Mt Mgahinga to the buffalo wall at the forest edge. After another briefing, we climb the makeshift ladders on the wall into the forest.
It is another strenuous climb before the rangers in the first team finally detect a gorilla nest site. Since each team is supposed to find its own site, Team 7 moves on. Slightly ahead, the rangers find a fresh gorilla trail. We cannot follow the trail but instead, have to backtrack until we find the site where the gorillas spent the night.
It rained the previous night so the soil is slippery. The thick undergrowth is also deceptive because one wrong footing can land you into a ditch. A few members of the other teams have already fallen.
All you can hear is the deathly quiet. Because humans are loud in their movements, we have scared the animals away. It is also a surprise that we do not encounter snakes.
As a light drizzle begins, at 11.40am our trucker, Idelfonse Gatete spots smashed gorilla dung under a tree. This means the gorilla slept in the tree. Since this is practical exercise, no one has to climb the tree to look for dung in the nest.
Other members of the team have moved on and call to us, indicating that they have found a nesting site with dung in it. First, papers indicating the site number and nest number are placed around.
Then, Elias Tushabomwe, the data entrant, captures the GPS coordinates of the site in the electronic notepad. Information about the weather, the surrounding vegetation and the nest number are also entered into the notepad.
There is a protracted discussion about the kind of vegetation around us, until the team decides it is herbaceous vegetation. Gatete says the site looks to be one day old so the data collectors begin putting on their gloves.
If the dung size had been large, we would have spent time looking for long silver hair. So, with a ruler, the sample collectors, Uketwengu Penjonga and Vianney Ndagiwenimana, measure the size of the dung. At 5.5cm, it is a juvenile gorilla. With wooden sticks, the two take one sample from the outer edges of the dung and put it in the sample tube containing ethanol. They leave the white sticks in the dung, to alert another group that comes across it.
The sample tube is labeled with the same data on the notepad, and then stored in the Ziploc bag. We move on to the next nest where the gorilla defecated and slept on its dung.
In the distance, we hear what sounds like a gunshot, but decide it is a gorilla breaking a tree branch.
Although a sample is taken from the smashed dung, it is difficult to know the age of the gorilla. In the third nest, the dung is also smashed, but interestingly, there are small droplets nearby, indicating that there was a baby gorilla in the group. The fact that there is a baby means the big pile of dung in the nest belongs to a female gorilla. Both samples are placed in different tubes.
At 12pm, it is time to move on, following the trail. Along the trail, the teams make observations about tracks made by other animals and traps made by poachers, which they enter the notepads.
Some of the hazards that the data entrants will face include falling into ditches, the extreme cold weather, swarms of bees, meeting wild animals and lack of clean water sources.
Luckily, that day we did not come across any animal because of the noise we were making. Real work for the second census team begins on April 4, 2016, when the teams will be divided between Uganda, Rwanda, and DR Congo. Arinaitwe’s Team 7 will be heading for Goma and they hope to end up on the Ugandan side of the Masiff in mid-May.
About the silverback gorilla
Some gorillas are not happy about sharing their females. The dominant male takes the females and as he produces male gorillas, he chases them out of the group, forcing them into a solitary live. During their solitary existence, silverbacks feed intensively and exercise, to gain more strength to attack a social group with a weak leader.
If the leader of the social group beats the silverback, it returns to solitary life and does more intensive training. It may also grab one or two females from the group with whom he may decide to start a family. However, if the Silverback beats the leader of the social group, he takes over the group and kills the young males in it, including the breastfeeding ones, so that it can begin a new family.
Problems of conserving gorillas
In Bwindi Impenetrable National Park, according to Arinaitwe, the threat is from the small size of the gorilla habitat.
“The Protected Area Boundaries are restricted and surrounded by populous areas, such as Kigezi region. In future, when the numbers of the gorillas grow, there will be no space for them to expand.”
Dr Muamba Tshibasu also says the instability is a determent to gorilla conservation.
“Stability enables conservationists to do monitoring and researching. Insecurity also means it is difficult to fight poaching. However, through increased joint patrols in the Virunga Masiff, we are addressing the menace of poaching.”
One of the emerging issues in wildlife conservation is the discovery of oil.
“If oil exploration goes on in DR Congo, 85 percent of the Virunga Mastiff will disappear and the impact on the ecosystem services will be irreversible. These countries signed some global conventions and we advise them to respect them to prevent the consequences of oil exploration.”
For instance, during the Texas oil spill, there was a loss of biodiversity in the spill area, and even though compensation was given, no amount of money can replace the damage to the environment.