Overview The western hoolock gibbon , the only non-human ape species found in India, faces severe threats to its survival in the Hollongapar Gibbon Sanctuary in Jorhat, Assam . The sanctuary is impacted by anthropogenic pressures, including habitat loss, fragmentation, and hunting, leading to a drastic decline in the gibbon population. A major challenge is the presence of a British-era railway line that bisects the forest, further fragmenting the gibbon's habitat. Key Challenges Habitat Loss and Fragmentation Like in most of their geographical range, the gibbon’s presence in Assam too has become severely restricted due to habitat loss and fragmentation. The expansion of settled agriculture and deforestation too have eaten into the gibbon’s domain, say researchers. Deforestation: Expansion of agriculture and settlements reduces available habitat. Railway Line: The Northeast Frontier Railway line splits the sanctuary, isolating gibbon populations. Jhoom Cultivation: Shortened cycles of slash-and-burn agriculture prevent forest regeneration. Hunting and Poaching Additionally, threats like hunting have led to the species being listed as among the most endangered of primates in the world. Gibbons are also secondary targets for hunters due to their loud vocalisations that can go on for up to 30 minutes. Hunting Pressure: Gibbons are targeted for meat and traditional medicine. Secondary Targets: Loud calls make them vulnerable to hunters targeting other species. Population Decline According to estimates, the gibbon population has plummeted from over an estimated 100,000 individuals to less than 5,000 . Drastic Reduction: 9 out of 10 gibbons have disappeared in recent decades. Small, Isolated Populations: Increased risk of in-breeding depression. Conservation Efforts Genetic Studies Aaranyak , a conservation NGO, is compiling genetic data of gibbon populations through faecal matter collected in forests to understand whether in-breeding and in-breeding depression are causes for concern. Source Population Identification: Identifying populations with high genetic diversity. Stress Level Analysis: Measuring cortisol levels to assess the impact of human proximity. Technology-Based Solutions The Habitats Trust (THT) , along with Conservation Initiatives , is working on technology-based solutions to identify gibbons in any particular habitat. Bio-acoustics: Using machine-learning models to identify gibbon vocalizations. Thermal Drones: Exploring the use of drones to detect gibbons in the forest canopy. Community Involvement Local communities too are becoming involved in the conservation of the species. Since much of the gibbon’s habitat in the hill tracts of Northeast India is owned and managed by resident populations, it is imperative that these communities are involved in conservation efforts. Community Ownership: Engaging local communities in forest conservation. Traditional Knowledge: Integrating local customs and laws related to forest conservation. UPSC Relevance This article is relevant to GS3: Environment and Ecology , specifically concerning biodiversity conservation, habitat loss, and the impact of human activities on endangered species. It also touches upon the use of technology in conservation efforts and the importance of community participation, aligning with topics in GS3: Science and Technology and GS3: Infrastructure (impact of railway lines). The case of the hoolock gibbon can be used as an example in Mains answers and essays on environmental conservation and sustainable development. Important Facts The western hoolock gibbon is the only ape species in India. The Hollongapar Gibbon Sanctuary is located in Assam. The gibbon population has declined drastically from 100,000 to less than 5,000 . Habitat loss, fragmentation, and hunting are major threats. Aaranyak and The Habitats Trust are key organizations involved in conservation. Bio-acoustics and thermal drones are being used for monitoring. Local communities play a crucial role in community-based conservation .