| Hainan Black-crested Gibbon (Nomascus sp.cf. nasutus hainanus) belongs to Mammalia, Primates, Hylobatidae, Nomascus. It only distributes in Hainan Island, P.R.China. It is now Class I of key Species of wildlife protected in China, and listed by IUCN as critically endangered and one of the world's 25 most endangered primates. It was once widely distributed over Hainan island. Because of the habitat losses and human hunting, it's distribution and population declined dramatically. Before the 1960s Hainan Gibbon was widely distributed across 12 counties in Hainan, with an estimated population of over two thousand individuals while By the early 1990s it was believed Bawangling National Natural Reserve was the only place with a viable population of no more than 20 individuals. The gibbon has been on the very edge of extinction.In order to save this critically endangered primates from extinction, East China Normal University, Shanghai, China together with Paris Zoological Society, France supported a five year field research in Bawangling National Natural Reserve from November, 2001 to January, 2006. The targets of this field work include the population distribution inside the reserve and the reasons which causes this distribution, why the population remains stable at about 20 individuals.During the 5 year field work, a long-term monitoring on Group A (7individuals) and Group C (4 individuals) were made. Research works about the song characteristics, population distribution and population dynamic, social group organization and its scale were made. Also investigations about the reserve management, local community, habitat structure, fragmentation, disturbance and the current threats to gibbon population were also made. The conclusions of the research work are listed as below:1. Now, there are at least 3 social groups and 2 solitary male inside the reserve, total population is more than 19 individuals. The compositions of the 3 social groups are: Group A 7 individuals, 1 adult male, 2 adult female, 2 juvenile and 2 infant; Group B 6 individuals, 1 adult male, 2 adult female, 1 juvenile and 2 infant; Group C 4 individuals, 1 adult male, 1 adult female, 1 juvenile and 1 infant. The main gibbon activity area is the south-west slope of Futouling ridge, Benggang ridge and Bengding ridge till the border of the primitive forest at Nanchahe,, the north-west slope of Shifeng ridge, area around Dongsanji ridge till Dong'erdagou valley and the road.2. The mean scale of the social group is 5.33 individuals, SD1.22, min4-max7 (n=9). Each group consist of, 1 adult male, 1-2 adult female and 2-4 offsprings.Inside Group A and Group B, there are two infants born in the same year. So it is for sure that both the adult female attend reproduction.3. The mean occurrence frequency of Hainan Black-crested gibbon's duet song is52.41% (min21%-max92%, SD 16.01%, n=24); during dry season is 53.88% (min28%-max92%, SD 16.90%, n=14), while during rain season is 50.35% (min21%-max71%, SD 15.31%, n-10). The difference between dry season and rainseason is not significant. The highest frequency occurs in August 71.43%, the lowestis during March 31.28%.4. Almost all the duet songs start before 11: 30 (98.05%), and the major part of the songs start between 6: 30 and 9: 30(68.09%), 6: 30-7: 30 has the highest percentage (28.79%). The mean time of the song starting is 7: 56 (min5: 58-max13: 50, SD 1: 27, n=212); during dry season it is 8: 22 (min6: 23-max13: 50, SD1: 25, n=lll); during rain season it is 7: 28 (min5: 58-max13: 45, SD1: 20, n=101), The difference between dry season and rain season is significant The song starting time is correlated with the sun rise.5. The mean lasting time of duet song is 13.91min (min6.00-max30.00, SD 5.07, n=193); during dry season is 14.19min(min6.00-max30.00, SD 5.44, n=113); during rain season it is 13.51min (min6.00-max29.00, SD 4.51, n=80). The difference between dry season and rain season is not significant.6.The mean times of great call during duet song is 4.59(min2-max9, SD 1.84, n=22).The mean time between the first great call and the beginning of the song is 4.18min (min1-max8, SD 2.32, n=22) .The mean time between each great call is 2.70min (min1.5-max5, SD 0.96, n=22) . The mean time between the last great call and theend of the song is 2.64min (min0-max10, SD2.70, n=22).7. The vertical distribution of vegetations of Hainan Black-crested gibbon is clear. Between 375meter and 800 meter, there a secondary forest, pine plantation, fruit tree plantation and grass land. Between 800 meter and 1100 meter, there are valley and mountain rain forest. Between 1100 meter to 1300 meter, there is mountain ever-green broad-leaf forest. Above 1300m, there are mountain dwarf foest The total area used by gibbon is about 600 ha, including 380 ha used by Group A and Group C, 220 ha used by group B.The fragmentation of the habitat caused by a road and electric line is not serious. But the road cut off the gibbon to reach the area of Heiling ridge where once gibbon distributed. The habitat is completely surrounded by road, pine plantation, fruit tree plantation and grass land. Thus cause the restoration of primary forest in new area become very difficult. The limitation of habitat area may already obstruct the population increasing.The limited primary forest area, economical plantation and construction, fire wood collecting, poaching and illegal logging pose disturbance to the current gibbon habitat.8. The reserve management is suffering from shortage of manpower and insufficient fund allocation. Poaching and illegal logging can not be fully sopped. The poverty of the local minority community cause serious dependence of natural resources.The limitation of usable habita, poaching and illegal logging, economical plantation and construction, Limitations in Reserve Management and Funding Allocation and the too small population pose direct threat to the survive of Hainan gibbon.It is suggested that the road which isolates Heiling ridge from the current gibbon habitat should be wasted as quickly as possible, in order to provide the population an immediately usable potential habitat. Forbid the construction of any new power dams around the reserve, and waste the power dams already constructed. Stop economical plantations around the reserve; gradually eliminate pine plantation and other plantations inside the reserve so to provide the space for primary forest recovery. Further strengthen the control of gun in the local minority community, gradually forbid the gun usage of local people so that this direct threat to the gibbon can be completely eliminated. Implement a publicity campaign to raise awareness of the Hainan Gibbon conservation and efforts being made to conserve it. |
