The life of most primates is inextricably linked to the trees on which they survive. And the destruction of the trees means an inevitable death of the species. The hoolock gibbons of northeast India are one such species that are disappearing along with the destruction of their habitats.
The western hoolock gibbon (Hoolock hoolock) population has been decimated with a 90% drop in the last three decades as hunting, deforestation and governmental apathy leave the future of the species in jeopardy. The hoolock gibbons live almost all of their lives on trees and are rarely seen on the floor of the forest. They need large sections of dense forest land to survive.
Among primates, the hoolock gibbons are particularly susceptible to the loss of habitat due to degradation and fragmentation. Florian Magne, the executive director and founder of the HURO Programme which is dedicated to the Hoolock Gibbons says that the species is especially susceptible to the loss of their natural habitat.
She says that they cannot adapt to the degradation of their forests and are uncomfortable living on the ground where they face threats from humans and other wild and domestic animals. They also are easily tracked due to their loud calls. They also become vulnerable to diseases on the forest floor.
The hoolock gibbons are found in the four neighboring countries of India, China, Bangladesh, and Myanmar. All the three species, the Gaoligong Hoolock, the eastern Hoolock, and the western hoolock are dependent on uninterrupted patches of forests to guarantee their survival in the long term.
Hoolock Gibbons Cannot Survive In Isolated Patches Of Forests
All three species are extremely uncomfortable on the ground and are trapped if they cannot find trees nearby. They continue to become isolated as roads and other human activities force them into small patches of land.
Other than the depleting forest cover, the hoolock gibbons face other threats that come with human intervention in their areas. This entrapment causes them to live in isolated patches of forest cover which causes inbreeding that causes a drop in genetic diversity. This affects their health, and they become susceptible to diseases.
The hoolock gibbons also do not reach sexual maturity before the age of 10 and form a monogamous relationship. They are slow breeders and if a mate dies out, they may never breed again.
Forest degradation also causes infighting among the trapped hoolock gibbons for food and territory. Food scarcity begins to affect such isolated groups, and they die out soon.
Ensuring large areas of forest cover is the only way to ensure their survival. To ensure their survival, 27 stronghold areas have been identified with an area of at least 97 square miles (250 square kilometers) for their survival.
Together, these stronghold areas cover an area of 63,969 square miles (165,679 square kilometers) across these four countries. That is roughly the size of Bangladesh. 22% of the hoolock gibbon population is under extreme threat from loss of forest land and hunting, while 23.5% of their population face medium threat to their existence. 55% of the hoolock gibbon population live in areas with low threat levels.
The western hoolock gibbons suffered the maximum loss of forest land as 2,856 square miles of land were lost from 2000 to 2018. This has been linked to the expansion of agricultural land in Myanmar and India.
The decline of the hoolock gibbons has led to only around 3,000 of the western species surviving in the wild. Researchers have also called for trans-border conservation efforts to identify population strongholds where they face the maximum threat to their habitat and their survival.
The hoolock gibbons are indicative of the health of a forest. Their presence indicates that the forest in that area is thriving. Ensuring the protection of their habitat guarantees that the hoolock gibbons population thrives in that area.