Biodiv Sci ›› 2004, Vol. 12 ›› Issue (3): 324-332.  DOI: 10.17520/biods.2004039

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Factors influencing the population status of wild Chinese alligators (Alligator sinensis)

DING You-Zhong, WANG Xiao-Ming*   

  1. 1 School of Life Sciences,East China Normal University,Shanghai 200062
  • Received:2003-10-22 Revised:2004-02-16 Online:2004-05-20 Published:2004-05-20
  • Contact: WANG Xiao-Ming

Abstract: During April-August 1998, 200 questionnaires were distributed and collected in each of 200 towns and villages in the National Chinese Alligator Nature Reserve in Anhui Province. Based on the results of the questionnaires, quantitative nocturnal spotlight surveys were carried out from July to October of 1999, 2000, 2001, 2002 and 2003 in areas most likely to have wild alligator populations. The survey area included 36 sites in five counties or municipalities (Xuancheng, Jingxian, Guangde, Langxi, Nanling) in Anhui Province, seven sites in Changxing County and Anji County of Zhejiang Province, and two sites (Fuxijian and Dahanjie) near Yixing City in Jiangsu Province. Based on these surveys we estimate that the current size of the wild Chinese alligator population in Anhui and Zhejiang Provinces is 120 individuals. The population is fragmented into 23 isolated small local populations with 1-10 individuals each. No alligators were found in Jiangsu Province. Analysis of our data revealed that the wild Chinese alligator population and its distribution have declined sharply since the 1950s. The current population size of wild Chinese alligators has declined an estimated 76.5% from its levels in the 1980s. However, the population appears to have been stable from 1998 to 2003 with an estimated 120 individuals. The factors most responsible for the population decline have varied over the last fifty years but overall have been habitat fragmentation and degradation, hunting, natural disasters (floods and drought), low productivity and pollution. From the 1950s to 1990s, habitat loss and the killing of alligators were the most significant factors. Presently, killing of alligators is less of an issue but the loss of habitat has been virtually complete. Therefore, the highest priority for conservation of Chinese alligators must be habitat restoration as the first step towards reintroducing alligators by releasing captivebred individuals. In addition, the potential consequences of environmental pollution and reduced genetic diversity of wild Chinese alligator population must also be addressed.