Habitat Characteristics of the Endangered Hoolock Gibbons of Bangladesh: The Role of Plant Species Richness

Hoolock gibbons ( Hoolock hoolock ) are endangered small apes occurring in Bangladesh, India, Myanmar, and south China. All known populations have undergone declines primarily due to habitat destruction or alteration. We examined the influence of area of natural forests, area of plantations, area of agricultural land and edible plant species richness on the hoolock gibbon numbers from 22 sites in Bangladesh using multiple regression analysis. Area of natural forests and plantations were not linked to hoolock gibbon numbers, whereas area of agricultural land and edible plant species richness were both significantly linked. Higher edible plant species richness was directly related to hoolock gibbon numbers, while the area of agricultural land was inversely related. This is the first quantitative study illustrating the importance of these two variables with hoolock gibbon numbers. We also analyzed the existing habitat characteristics in two of the largest hoolock gibbon populations in Bangladesh: Lawachara (42 individuals) and Kaptai (84 individuals). Trees in Lawachara were generally smaller compared to those in Kaptai. Artocarpus , Tectona , and Dipterocarpus were the three most important genera in both sites, although Artocarpus was more important in Lawachara. Each site also had an abundant variety of tree species utilized by hoolock gibbons for food. We discuss the current context of primate conservation in Bangladesh and suggest that the current conservation priority for gibbons in the country should be protection and improvement of habitat.