Endangered Species: Hoolock Gibbons of Bangladesh
The Hoolock gibbon (Hoolock hoolock) are species of global conservation importance and are specifically limited to only tropical Asian forests in India, Myanmar, China and Bangladesh. Currently hoolocks are categorized as critically endangeredand globally as endangered by the IUCN World Conservation Union in Bangladesh and are considered to be one of the 25 most endangered primate species in the world. Several populations of this species have become extinct during the last 15 year but some have been hanging on in the fragmented regions despite the tremendous pressure. Their populations have declined drastically in recent years due to habitat loss, forest fragmentation, gas exploration, illegal hunting and poaching. Conservation of the remaining Hoolock Gibbons of Bangladesh rests on the future management and planning of their patchy forest habitats. Illegal deforestation, habitat restoration and translocation of individuals should be done to maintain these last Hoolock Gibbon populations in Bangladesh.Hoolock populations may be viable to exist in the long run in Bangladesh provided necessary measures are taken to protect and improve their existing habitats.The hoolock gibbon is an umbrella species living in the semi evergreen deciduous forests of different regions in Bangladesh and their survival through management will also benefit other species that are components of closed-canopy forests.
Bangladesh’s location in the Indomalayan Realm makes a country to be home to a wide diversity of wildlife. Residing in this small area there are hundreds of species. Gibbons is such small species of apes distributed in south and Southeast Asia. They are socially monogamous small apes that hold a very important position in the ecology of tropical forests. But over years, all gibbon species have undergone massive declines in population size primarily due to habitat destruction and alteration. In Bangladesh, they currently hold the critically endangered status and are also endangered worldwide (IUCN, 2015). Among the 13 gibbon species, hoolock gibbons Hoolock hoolock Harlan is perhaps under the greatest threat throughout their geographic range. Total counts of this species in India is slightly larger than 2600 individuals scattered across the states of Arunachal Pradesh, Assam, Meghalaya, Mizoram and Tripura (Das et al. 2003) and the hoolocks in Bangladesh are considerably much smaller in numbers. Key actions are necessary to conserve the last hoolocks in Bangladesh.
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Most information about the preset distribution of Hoolock gibbons of Bangladesh were taken from different studies which surveyed the population of the Gibbons in the northeastern and southeastern regions of Bangladesh both consisting of semi-deciduous moist evergreen forest patches suitable for Gibbon Habitat. Detailed surveys also have been carried out in India between 1995 and 2001 (under Indo-US Primate Project) and in Bangladeshbetween 1990 and 2001.Locations of Western Hoolock Gibbon were recorded from transects. Extent of occurrence and area of occupancy were calculated as defined by the IUCN Red List Criteria and Categories.
Another study by Md Anwarul Islam, 2009, followed similar procedure for surveys with consultation by for identifying possible locations of Hoolock Gibbon groups. Every 5-10 minutes the members of the team would stop to look around for signs of Hoolock Gibbon presence.This included hearing of calls or scanning the tree line with binoculars for Hoolock Gibbons in the canopy and looking for important fruiting trees. When calls were heard, attempts were made to assess the direction of the call and then to locate the group. Some studies also used GIS mapping to present the distribution of the Gibbons in different regions.The coordinates of the encounter were determined using a hand-held Global Positioning System device. The GPS coordinates were recorded into a computer and the locations of the groups plotted on digital and paper maps of the area producing a map.
3.1 Causes of Species Decline
The population of Bangladesh is currently 161 million and rapid urbanizations is quickly shrinking our forest reserves.Slash-and-burn shifting cultivation also known as Jhum cultivation is the main factor leading to the destruction and fragmentation of gibbon habitat, but conversion of tropical forest to teak plantations, betel leaf plantation, and encroachment of forest land for settlement are equally important factors for their decline. Worldwide, many other traditional uses of forests for commercial purposes contribute to habitat degradation including introducing exotic tree species, extracting tree bark, extracting fuel wood, extracting timber, and livestock herbivory.The species is threatened by habitat loss and by hunting for food, for oriental medicine and for the pet market. Gas exploitation in some regions also add up to the loss of habitat. Alongside, the slow but deadly impacts of climate change are also at play, although there are not many studies which show the direct linkage with Gibbons. Overall, key features of the habitat may disappear without necessarily reducing the area over which hoolocks can possibly live, effectively reducing the population.
3.2 Present Status (Abundance, Distribution, Geographic Range)
Hoolock gibbons are exclusively forest dwelling species and depend on a contiguous canopy. They are found in broad-leaved, moist deciduous forest, deciduous forest with tall deciduous trees and evergreen understories, sub-tropical broadleaf forests, from mountainous, hill, valley, slope and lowland forests to wet evergreen and semi-evergreen forests often consisting of interspersed trees and bamboos as well as various conditions of forest, including primary, secondary, and regenerating of tall trees with thick undergrowth.Starting in the east and moving roughly westerly, they are found only in China, India, Myanmar and Bangladesh. Much of their habitat is extremely fragmented in these regions.
They are distributed in the various northeastern states in India, with a current total population of more than 2600 individuals (Molur et al. 2005). In Bangladesh, their populations had been estimated to be over 3000 individuals in the eighties (Gittins & Akonda 1982, Gittins 1984). This number had subsequently decreased to about 200 individuals in the early nineties (Islam & Feeroz 1992) and the declining trend continues in many areas of Bangladesh, with some areas having lost all of their hoolock gibbons (Feeroz 2001, Das et al. 2003, Islam et al. 2004). The most recent estimate is close to 300 individuals (Islam et al. 2006), indicating that the species is persistently holding on in limited patches of a suitable habitat. The location of Hoolock Gibons in Bangladesh are listed in a table below in the areas of Sylhet, Chittagong and Cox’s Bazar. The figure also shows the distribution of the species in Bangladesh. Besides this, they can also be found in Dhaka Zoo and Dulhazara Safari Park.
Table 1 Number of hoolock gibbons in 22 sites in Bangladesh (from Islam et al. 2006).
Site Groups Individuals
Baralekha 3 10
Lathitila 3 9
Lawachara 12 42
Adampur 8 21
Rema-Kalenga 1 2
Satchari 2 7
Korerhat 0 0
Hazarikhil 1 4
Bamu 4 14
Bengdheba 3 9
Kapta 26 84
Rampahar 5 16
Chunati 0 0
Satghar 0 0
Fashiakhali 0 0
Dopachari 3 7
Bhomarighona 0 0
Himchar 0 0
Hnila 0 0
Inani 2 6
Ukhia 5 14
Teknaf 2 2
4 Policy and Legislations for Conservation
The government of Bangladesh is a signatory to the Convention on Biological Diversity (CBD) and the Ramsar Convention.Bangladesh made its first step of saving the wildlife and wilderness when it promulgated the Bangladesh Wildlife Act in 1974. This initiative gave a boost to the Government Forest Department in recruiting wildlife biologists, declaring few areas as wildlife and nature conservation divisions, protected areas (PA) as wildlife sanctuaries, national parks, game reserves, bird sanctuaries, etc. The forest department revamped the wildlife act of 1974. This has been thoroughly improved and modified and re-enacted as the Wildlife (Conservation and Security) Act 2012 in 2012.It has allowed more and more areas to be brought under the PA systems. We currently have 39 Pas and mong these, 38 are forest based and are managed by the forest department.Among the 38 Protected Areas of the country, 4 support only cetaceans while the rest of these Protected Areas support 11 to 50 mammalian species. Among this, the Lawachara National Park and adjoining areas of West Bhanugach Reserve Forest in the northeast are known to support the largest and continuous population comprising of 59 gibbons in 16 groups (Islam et al., 2004, 2006; Österberg, 2007).The hoolock species has also been under the 3rd schedule of Bangladesh Wildlife Act 1974 and urged the government to declare all hoolock habitats as protected areas either as national parks or as sanctuaries. Overall, major legislative policies and approachestaken by the government for biodiversity conservation in the country are listed below:
• The western Hoolock gibbon is listed on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix I and on schedule I of the Indian Wildlife Protection Act of 1972.
• The hoolock gibbon is protected under Schedule-I of the Wild Life (Protection) Act of India, which prohibits its killing or capture, dead or alive.
• The eastern hoolock gibbon is categorized as Vulnerable on the IUCN Red List (Brockelman & Geissmann, 2008) and as a Class I species under the Chinese animal conservation laws.
• It was designated as one of the top ten threatened gibbon species in a resolution resulting from the 2002 Congress of the International Primatology Society in Beijing.
• Conservation measures were undertaken for the gibbons in Myanmar have been by the Forest Department in collaboration with the Wildlife Conservation Society (WCS).
The first legal protection for gibbons in Myanmar is under the Wildlife Law (1994), Article 15 w• All three of Myanmar’s gibbons are listed as Appendix I in the Convention on International Trade in Endangered Species of Wild Fauna and Flora, to which Myanmar acceded in 1997.
• The Nature and Wildlife Conservation Division of the Myanmar Forest Department and WCS also collected gibbon census data from the Hukawng Tiger Reserve.
Figure 4 Protected areas in Myanmar in the range of the hoolock gibbon
5 Interventions taken by Government and NGO for Conservation
• Wildlife Trust of Bangladesh has taken many initiatives to protect the hoolock gibbons in Bangladesh.
• International organizations such as Zoo Outreach Organization initiated a network for Hoolock Gibbon stakeholders through mail, workshops, direct and indirectly through contacts by collecting names, addresses, emails, with an objective to enhance communication between Hoolock Gibbon stakeholders throughout Bangladesh, India and wherever the students of WHG live.
• The Forest Department has already developed plans of restoring habitat and boosting hoolock gibbon and other primate populations in Lawachara and Rema Kalenga (FD/MOEF 2000a, FD/MOEF 2000b).
• The Wildlife Trust of Bangladesh, Bangladesh Forest Department and Zoo Outreach Organization, in collaboration with several institutions, have organizeddifferent initiatives to protect the species.
• WTB has been assisting the Forest Department in the protection of nature and threatened species conservation.
• Different workshops has been supported by US Fish and Wildlife Service, Great Ape Conservation Fund, Margot Marsh Biodiversity Foundation Primate Action Fund, Conservation International, Twycross Zoo–East Midlands Zoological Society and Apenheul Primate Conservation Trust, the Netherlands.
• Planning of Gibbon Conservation Group is ongoing in four important gibbon habitats at Lawachara National Park (north-east), Kaptai National Park (south-east), Inani Reserved Forest (southern), and Bangdheba (southern) in Bangladesh.
• Community conservation initiatives will be taken in four different locations (Inani Reserved Forest, Bangdheba, Kaptai National Park, and Lawachhara National Park).
Figure 5A community involvement conservation initiative of western hoolock gibbon by Gibbon Conservation Alliance
6 Gaps in Conservation and Interventions
The forested lands administered by Bangladesh officially represent about 17% of the total land area of Bangladesh, although the true area of forest cover is likely to be less than 6% (Gain 2002). Within the forestlands, there are about 16 protected areas which are recognized merely on paper. Illegal harvesting of forest products continues to go on and are often done in connivance with the forest officials. Inadequate protection and poor management systems of the hoolock habitats were identified as the major impediments for hoolock conservation (Ahsan, 2000). Most of the areas within protected forest patches are fragmented and have areas of agricultural land, small villages, grazing land and other human altered habitats that make the quality of these areas extremely poor. Enforcement in Bangladesh is virtually nonexistent, even in these protected areas. Construction of new roads, highway and railway lines have been fragmenting the existing mammal habitats and also creating obstacles for the movement of animals. Hoolock Gibbons are trapped both side of the railroad in Lawachara National Park. There is a lack of commitment and understanding of the value of protected areas in our country.
Other key challenges to gibbon conservation and gaps in interventions in Bangladesh include the lack of capacity and skills in the Forest Department, and the lack of awareness among the local communities living around gibbon habitats. People living in and around protected areas can be made to understand that the presence of certain wildlife species, such as hoolock gibbons. This may result in good quality habitat.
7 Additional Measures
The following points list out the additional measures that can be taken in order to protect the gibbon population. Alongside, I have also attached a potential gibbon conservation action strategy in the annex of this report.
raining and capacity building of the
Forest Department officials is paramount to conservation of wildlife and a long-term plan to
develop the Forest Department is in order.
• Training and capacity building of the Forest Department officials is paramount to conservation of wildlife and a long-term plan to develop the Forest Department is in order.Existing protected areas should be better protected, with increased staff, anti-poaching camps and regular patrolling. Measures should be taken to control jhum cultivation as well as hunting for meat. Awareness campaigns should involve the churches and the village headmen to promote conservation measures, and programs should be set up for the regular monitoring of the gibbon populations in select sites
• A number of important known habitats for hoolock gibbons that are outside the protected area network should be declared as wildlife sanctuaries, conservation reserves and community reserves.
• The government’s attitude towards the remaining forest patches needs to change. Currently, the revenue generating forestry practices need to be replaced by an ecosystem-friendly forestry that supports people and life.
• Translocation of isolated gibbons living in degraded areas to parts of the forest where they could survive.
• Improvement of habitat should involve carefully planned plantations of mixed native species providing food and habitat for hoolock gibbons.
• Villagers living around important habitats should be carefully incorporated into conservation plans to prevent further degradation of these habitats by conversion to agricultural land. Consideration must also be given to providing for people whose livelihoods depend on the forest.
The hoolock gibbon still occurs in all different regions in Bangladesh but in much depleted numbers. The gibbon is nowhere abundant due to several reasons and except a few areas, it is found in scattered groups where their survival is doubtful in the long term.Therefore to protect this species from extinction necessary steps have to be taken starting from national conservation strategies to transboundary conversation and monitoring giving these species access to more food and better habitats.
1. Österberg, P. (2007). Going, going, gone? The Gibbon’s Voice (Newsletter of the Gibbon Conservation Center, California, USA) 9(1): 1-3.