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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (9): 78-89.doi: 10.11707/j.1001-7488.20150911

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Survey for the Breeding Biology and Danger Status of the Bearded Vulture Gypaetus barbatus in the Qinghai-Tibetan Plateau

Su Hualon1, Li Bajin2, Yao Yong2, Tang Yang3, Zhang Yong4, Golok Druk Kyab5, Wang Yanming6, Jiawu Cairang7, Wang Ying8   

  1. 1. Research Institute of Forest Ecology, Environment and Protection, CAF Key Lab. of Forest Ecology and Environment of State Forestry Administration Beijing 100091;
    2. Forestry Bureau of Yajiang County of Sichuan Province Yajiang 627450;
    3. Forestry Bureau of Mangkang County of Tibet Autonomous Region Mangkang 854500;
    4. Gahai-Zecha National Nature Reserve Administration Bureau of Gansu Luqu 747200;
    5. Nyanpo Yutse Environmental Protection Association Jiuzhi 624700;
    6. Qinghai Lake National Reserve Administration Bureau Gangcha 812300;
    7. Sanjiaocheng Sheep Stud Farm of Qinghai Province Gangcha 812300;
    8. Kunming Institute of Financial Business Kunming 650228
  • Received:2014-03-30 Revised:2014-07-26 Online:2015-09-25 Published:2015-10-16

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Abstract:

[Objective] Bearded Vulture (Gypaetus barbatus) is listed as one of the first-grade national protected wildlife species in China, which means the population of Bearded Vulture is at the margin of extinction. Nevertheless, very little information has been published on the basic aspects, such as the reproductive ecology, population status and endangerment mechanism. For the sake of protection of this endangered species, it is necessary that systematic researches should be carried out on its reproductive ecology, the human disturbance impact on its population dynamics, the mechanism of endangerment, the negative factors from human and nature and its own defects of behaviors responding to the changes of environment. The objective of this study is to curb the tendency of endangerment of Bearded Vulture and other endangered species, and find the strategy to save the species from extinction in the wild. [Method] Study area:The survey was carried out in the Qinghai-Tibetan Plateau from 1991 to 1992 and from 2010 to 2013. The survey covers the work area includes the following:1) Changdu, Linzhi, Nagqu, Lhasa area of Tibet Tibetan Autonomous Region; 2) Ganzi, Aba Autonomous Prefecture of Sichuan Province; 3)Haibei, Haixi, Guoluo(Golok) and Yushu Autonomous Prefecture of Qinghai Province; 4)Gannan Autonomous Prefecture of Gansu Province. In these areas, there are 7 breeding places of the Bearded Vulture to be found. Data collection:Observations of daily activity behavior were performed for some nests, in order to determine the reproductive parameters. The breeding success rate is based upon the number of young fledg/number of breeding pairs in the winter of 2010 to the autumn of 2013. The data were not included in the uncertainty whether the young birds flew out of the nest. In view of the lack of investigation data with regard to the exact number of breeding pairs in a large enough area (>10 000 km2), therefore, the territory area can be converted only by the distance between the nests of 2-3 pairs in the suitable breeding habitat. As for population structure, survey data were collected by using transect investigations which mainly was conducted with motor vehicle, sometimes on horseback or on foot, and random observation samples (mostly from vantage points with good views over the sampling areas, also including observation on the carcasses). These investigations were conducted for 48 days from 1992 April to 1993 late February and 103 days from 2010 early December to 2012 late October, respectively. Each Bearded Vulture sighted was classified to one of four age classes: juvenile (<3 years), immature (3-4 years), sub-adult (4-6 years) and adult (>6 years). According to the total population size of the Himalayan Griffon Gyps himalayensis that has been reported, the Bearded Vulture breeding nests were compared with breeding nests of the Himalayan Griffon at the same period (from the end of 2010 to the end of 2012) to estimate the total breeding population size of this species. [Result] The results indicated that laying date of the Bearded Vulture began in early December and lasted until late January (range from 7 December to 28 January, n = 4), and incubation period was 55 to 61 days (n = 3). Mean clutch size was 1.86, and 85.71% of nests contained two eggs (n = 14). The mean size of 3 eggs measured was 84.4 (83.1-88.3) mm in length and 68.03 (67.0-70.0) mm in width. Breeding success rate was 81.82% (2010-2012, n = 22). The altitude range of nest sites was from 2 600 m to 4 575 m. The average distance between the breeding pairs was 35.84 km (25.10-47.3 km), and territorial area was 1 284.51 km2 (630.01-2 237.29 km2). The proportion of juveniles was reduced from 30.17% (n = 116) to 16.67% (n = 96) during the past 20 years, and the reduction rate was 44.75%. The proportion of adults was increased from 61.21% to 70.83% (since 1990). Those results suggested that the reproductive success rate and population quality decreased obviously. According to the published literature data for the evaluation and analysis, we believe that the total population size of the Himalayan Griffon in the Qinghai-Tibet Plateau would be about 100 000, therefore, the number of breeding pairs should be less than 50 000 (if considering the non-breeding birds, the value would be reduced by at least 30%). When the research project was implemented during the 2012 to 2013, a total of 11 Bearded Vulture's breeding nests and more than 390 Himalayan Griffon's breeding nests were found. According to the proportion calculation, we estimated the population size of the Bearded Vulture was less than 1 410 breeding pairs in the plateau region (about 2.5×106 km2). [Conclusion] It can be preliminarily determined that there would be more than 10 threaten factors to the Bearded Vulture. The modernization process of human society life, the establishment of various infrastructure projects, especially, people's lifestyles change in the remote mountainous area, would be important factors to affect the breeding success and population stability of the Bearded Vulture.

Key words: Bearded Vulture (Gypaetus barbatus), Tibetan Plateau, territorial area, population density, variation in population structure

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