Guwahati: Pressence of capped langurs have declined to only 11 of the 40 forest fragments surveyed by a team of researchers from some of the leading higher educational institutions in the upper Brahmaputra Valley. The study attributed this pattern to the loss of habitat and declining food resources.The lowland tropical rainforest fragments of the upper Brahmaputra Valley in Assam were once part of a vast, unbroken stretch of forests — a habitat of capped langurs and other primate species. However, studies showed that deforestation broke up these forests into smaller, isolated fragments.“Wildlife that once thrived in these habitats suffered significant losses, particularly in terms of habitable area and food resources. Among the affected species is the capped langur, the only colobine primate found in the upper Brahmaputra Valley,” stated a summary of the paper “Lost in Fragmentation: Occurrence of Capped Langur Trachypithecus pileatus in upper Brahmaputra Valley of Assam”.The study, recently published in the Journal of Asia-Pacific Biodiversity, revealed a concerning trend — capped langurs disappeared from seven of their previously known forest habitats in Assam.The research team was led by research scholar Neeharika Gogoi and assistant professor Narayan Sharma from the Wildlife Biology and Conservation Group, department of environmental biology and wildlife Sciences, Cotton University, Samrat Sengupta of the department of zoology, Debraj Roy College, Golaghat, and Bijay Basfore of the department of zoology, Pandu College, Guwahati. They encountered ten groups comprising 81 individuals of capped langurs and a solitary individual at eight sites. Besides direct sightings, the researchers confirmed the presence of capped langurs in three other sites through interviews with locals and forest staff. They recorded capped langurs in two human-habituated areas — Borajan and Chala. But in Chala, they observed just two female individuals traveling with a troop of rhesus macaques. In Borajan, the population declined from six individuals in 2019 to only three in 2022. As per researchers, this paints a bleak picture of the species’ prospects in human-dominated areas.
