By Simon Musasizi
For a long time, chimpanzees have been known to be strictly diurnal (non-nocturnal). They are known to be active during day, waking up to comb the forests for food before retiring to their nests at night to sleep. However, with increased human activities coming closer to their habitat, chimpanzees have changed their way of life. A video recorded by Sebitoli Chimpanzee Research Camp, which recently aired at Makerere University, suggests that climate change is forcing chimpanzees to adopt new ways of survival, including using the cover of darkness to search for food.
Cameras planted in Kibale national park, an extensive block of rainforest, captured chimps crop-raiding at night. Before raiding a maize field neighbouring the park, chimps display a high level of intelligence, using a tall eucalyptus tree growing at the border of the field to scan and see if the farmers have left.
Some individuals do not enter, staying at the edge guarding and looking out for any ‘enemy’ humans. Chimpanzees rarely transport food; they simply eat and leave.
But in this video, realizing that they only have a window of opportunity when the humans are asleep, they are seen ferrying maize into the forest. The most interesting part is how the chimps – incapable of swimming – use a fallen tree trunk to create a bridge over a water-filled fence-trench so that they can cross with their harvest.
Well, chimpanzees’ nocturnal activities have been reported during full moon periods. This is the first record of frequent and repeated nocturnal activities after twilight, in darkness, according to this new study, also published on the science journal plosone.org. These animals’ strange behaviour is attributed to the rapidly changing landscape highly impacted by human activities.
“Habitat destruction may have promoted behavioural adjustments such as nocturnal exploitation of open croplands,” reads the study. “Compared to previous centuries, the level of demographic pressure and the rate of habitat loss for wildlife caused by humans have dramatically increased.
Today anthropogenic activities, including commercial logging, poaching, mining, illicit trade of wild animals and agricultural land encroachment are severely threatening the tropical forests and the survival of fauna, including the great apes, our closest relatives. All great ape species are currently endangered and have experienced a considerable decline in population size and range in the recent years.”
Kibale national park, like many other protected areas, is under threat from human activities. The park is surrounded by farmers, who cultivate up to the boundary of the park, cutting off the forest from other, neighbouring protected areas.
Previously, the park was connected to protected areas, such as Queen Elizabeth national park, Bugoma and Budongo forest reserves and Murchison Falls national park. Then, animals used to move freely all the way from Congo through Queen Elizabeth to Kibale and Murchison Falls, all the way to South Sudan’s Nimule national park.
Over time, however, this wildlife corridor has been lost due to heavy settlements and agricultural activities on forests under the watch of National Forestry Authority (NFA).
“Our protected areas are no longer interconnected. That connectivity has been lost. You find Kibale is an island,” says Charles Tumwesigye, Uganda Wildlife Authority (UWA)’s deputy director for conservation.
Forest reserves such as Matiri and Kagombe that play a big role in linking Kibale to Murchison have been heavily encroached on – with urban centres cropping up.
For example, while Kyenjojo derives its name from the Rutooro word “enjojo” (elephants), referring to “the place where elephants live,” the town has since become a stumbling block to easy movement of elephants. Further in the north, Murchison, too, is isolated, hence persistent problems of crop raiding, as animals try to trace their routes.
“When the colonialists were creating national parks, they created buffers,” Tumwesigye says. “If you look at the three first national parks [Queen Elizabeth, Kidepo and Murchison Falls\, they all had buffers. Queen Elizabeth had Kigezi wildlife reserve and Kyambura wildlife reserve as a buffer.”
The argument then was that the protection would be in the parks and whichever animal strayed into the buffer zone would still be safe. But with population growth, people have cleared all these buffers, cultivating up to the boundaries of the parks. According to Tumwesigye, as the population increases, there is even more pressure to de-gazette protected areas to provide land for people.
“If government doesn’t take necessary steps and restore some of those corridors, especially the major corridors, we will continue to experience human-wildlife conflicts,” he warns.
The major corridors according to Tumwesigye are Queen Elizabeth-Kyambura-Katsyoha-Kitomi, Murchison falls-Aswa Lolim-East Madi-Nimule and Pian Upe-Iriri community wildlife reserve-Bokora-Matheniko-Karenga-Kidepo valley national park.
According to Tumwesigye, the connection between Queen Elizabeth and Katsyoha-Kitomi remains a narrow corridor of about 200metres, and yet this is a big connection for elephants. In Kibaale district, most of the forest reserves in the wildlife corridor are 100 per cent encroached. These include Guramwa, Kanaga and Ruzaire, among others.
While humans have been present in primate habitats for generations, the current rate of forest destruction and fragmentation has had great impact on wildlife.
Since 2009, the Sebitoli research camp has been monitoring the extreme north community of chimpanzees. Seventy-two chimpanzees were individually recognised out of an estimated number of 80 individuals. Some 40 per cent of them were identified with limb mutilations most likely due to snares.
“Wildlife is trapped. They are like in prison; when they move out, they are either in people’s gardens or homes,” says Charles Ariani, National Forestry Authority (NFA)’s sector manager of Kagadi sector.
This worries conservationists that it may affect the gene pool of wild animals because they will end up reproducing amongst family members. That affects their resilience to diseases because of limited variability of genes.
“In such a scenario, if there is a disease outbreak, it will sweep the entire species of animals,” says Ariani.
White rhinos, derbys and oryx have since become extinct in Uganda, with ostriches, and lions facing the same threat of extinction. Uganda is widely known as the primate capital of the world, with over 10 species of primates among which are the most sought-after gorillas and chimpanzees.
Chimpanzees are known to be sensitive to logging due to their territoriality, and their frugivorous (fruit-based) diet.
However, chimpanzees have high cognitive abilities. These enable them to use botanical skills to discover and exploit fruits in the forest habitat according to dynamical temporal patterns, to access hidden food resources using tools, to cooperate to achieve a common goal such as hunting, patrolling: or even to use the pharmacological properties of plants to self-medicate.
Nevertheless, the acquisition and transmission of such techniques and behaviours require a long period of social learning. This long time of social learning might not fit in the rapid changes of environment and of the local population perception towards chimpanzees, which occur in areas where habitat encroachment within chimpanzee habitat increases encounters with humans and consequentially chimpanzee aggressive behaviour.
Whether chimpanzees are flexible enough to adapt to their rapidly changing habitat and to the changes in the attitudes of local people regarding crop loss is a major concern for those working for their survival.