Population assessment of the endangered Western Hoolock Gibbon Hoolock hoolock Harlan, 1834 at Sheikh Jamal Inani National Park, Bangladesh, and conservation significance of this site for threatened wildlife species

Abstract

Sheikh Jamal Inani National Park (Inani) is a wildlife habitat in Bangladesh located under the Cox’s Bazar South Forest Division, Cox’s Bazar. It constitutes significant habitat for the charismatic and globally ‘Endangered’ Western Hoolock Gibbon Hoolock hoolock in Bangladesh. Here, we show that Inani is a poorly-known gibbon habitat with a population of seven groups, comprising a total of 18 individuals. Among them, 77.8% were adults (males and females), and 11.1%, 5.6%, and 5.6% were sub-adults, juveniles, and infants, respectively, indicating low reproductive output. Five of seven groups had no offspring present in the group, and the mean group size of 2.57 individuals/group is low compared to other habitats in Bangladesh. Beside Western Hoolock Gibbon, Inani is home to many threatened wildlife species. The first record of the Slaty-backed Flycatcher Ficedula erithacus in Bangladesh occurred in Inani, adding this new species to the national bird checklist of Bangladesh. The presence of the globally ‘Endangered’ Asian Elephant Elephas maximus, Phayre’s Langur Trachypithecus phayrei, & Elongated Tortoise Indotestudo elongata and the globally ‘Vulnerable’ Northern Pig-tailed Macaque Macaca leonina, Capped Langur Trachypithecus pileatus, Indian Leopard Panthera pardus, & Asiatic Softshell Turtle Amyda cartilaginea highlight the importance of Inani as a conservation area in Bangladesh. The Western Hoolock Gibbon and other threatened wildlife of Inani are now on the verge of local extinction due to a sharp increase in forest resource extraction resulting from the recent influx of large numbers of Rohingya refugees from Myanmar, many of whom have settled around Inani. Through stakeholder interviews in the area, we have identified feasible and measurable conservation actions at Inani that are urgently needed to prevent further loss of wildlife and to protect this important gibbon habitat.

Population of the Javan Gibbon (Hylobates moloch) in the Dieng Mountains, Indonesia: An updated estimation from a new approach

“…The fixed-point count was used owing to its efficiency and suitability for surveying gibbons, based on its call ( Brockelman and Srikosamatara 1993 , O'Brien et al 2004 , Whittaker 2005 , Buckley et al 2006 , Cheyne et al 2008 , Cheyne et al 2016 , Hamard et al 2010 , Kabir et al 2021 ). At each sampling site, three listening posts (LPs) were located on an either linear or triangular formation on the ridge or at a higher elevation to cover a wider listening area free from disturbing noise ( Brockelman and Ali 1987 , Cheyne et al 2008 , Höing et al 2013 ).…”