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Alligator sinensis 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Crocodylia Alligatoridae

Scientific Name: Alligator sinensis Fauvel, 1879
Common Name(s):
English Chinese Alligator, China Alligator, Chinese Alligator
French Alligator de Chine
Spanish Aligator de China
Taxonomic Source(s): Uetz, P., Freed, P. and Hošek, J. (eds). 2018. The Reptile Database. Available at: http://www.reptile-database.org. (Accessed: 03 March 2018).

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A1b; B1ab(ii,v)+2ab(ii,v); C1+2a(i) ver 3.1
Year Published: 2018
Date Assessed: 2017-07-31
Assessor(s): Jiang, H. & Wu, X.
Reviewer(s): Manolis, C. & Isberg, S.
Facilitator/Compiler(s): Ross, J.P.
Justification:

Its extremely restricted distribution, very small numbers of adults in the wild, and drastic decline over the past three generations all justify an assessment of Critically Endangered for Alligator sinensis. Ongoing efforts to protect the few wild individuals and habitat localities, reintroduction and a large captive breeding stock may be insufficient to ensure survival of this species.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Historically widely distributed in the lower Changjiang (also known as Yangtze) River system in southeastern China (Huang 1982, Chen et al. 1985), Alligator sinensis currently is only known from a small region in southeastern Anhui Province, a fraction of its former distribution (Thorbjarnarson et al. 2002). Reports of very low numbers of wild A. sinensis in Zhejiang and Jiangsu Provinces (Manolis 2002, Webb 2002) have not been confirmed in recent years, and certainly no breeding populations occur outside Anhui Province.

The current distribution of the species is restricted to extremely small fragments of its former range in southeastern Anhui Province (Thorbjarnarson et al. 2002). By the late 1980s wild A. sinensis remained only in Anhui Province, principally in small ponds in agricultural valleys and hills in five counties (Nanling, Jinxiang, Guangde, Langxi, Xuancheng), which together comprise the Anhui National Nature Reserve for Chinese Alligator (ANNRCA). Outside the ANNRCA, including all sites where alligators were previously found bordering the Yangtze River (Wuhu, Ningguo and Dongtu counties), Anhui Research Centre for Chinese Alligator Reproduction (ARCCAR) staff report alligators were extirpated during the past 30 years. Site inspections and review of status were conducted by IUCN SSC Crocodile Specialist Group members in 2016 (Platt et al. 2016, Manolis et al. 2016).
Countries occurrence:
Native:
China (Anhui)
Additional data:
Estimated area of occupancy (AOO) - km2:5Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:43
Number of Locations:1Continuing decline in number of locations:Unknown
Upper elevation limit (metres):400
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Surveys in 2005, 2011 and 2015 conducted by Anhui Normal University and ANNRCA indicated that Alligator sinensis were distributed among 19 fragmented habitats (ponds) (see Table 1 in Jiang et al. 2006). Within the ANNRCA, only 32 alligators were observed in 7 of 13 designated sites, two old sites and two new sites, and an additional eight sites with tracks. The largest groups contained a maximum of 10-11 animals and one adult female. In some cases these are small or remnant populations with little or no breeding known (Jiang et al. 2006, Wu et al. 2008).

Despite establishment of the ANNRCA, the wild population has continued to decline, and current population estimates are <25% of 1980s levels. Results of population surveys can be summarized as:
  • In the early 1980s, surveys in Anhui Province estimated the wild A. sinensis population to be at least 300 individuals, comprised mostly of juveniles or sub-adults [Watanabe, cited in Groombridge (1982)].
  • In 1985 and 1987, a more extensive survey of 129 villages (423 bodies of water) in the ANNRCA was organized by ARCCAR, and the population was estimated at 735 animals. Based on this estimate, and that between 1979 and 1983, 212 wild A. sinensis were collected to stock the ARCCAR, it is likely that around 1,000 wild A. sinensis were in Anhui Province during the late 1970s.
  • Zhu (1997) provided population estimates of 378-747 for the ANNRCA from 1985 to 1994. However, it is unclear how these population estimates were derived.
  • In 1994, the total population was estimated to be 667-740 individuals, based on the assumption that only one-third of the sites within the ANNRCA were surveyed (Li et al. 1996). But because the key locations actually known to have Chinese Alligators were visited, the validity of this extrapolation is questionable and the population figure is most likely to be an overestimate.
  • In 1997 the population was estimated to have been reduced to approximately 400 animals (Wan et al. 1998), but no details were provided.
  • Thorbjarnarson et al. (2002) provided data indicating the total wild population had declined from approximately 1,000 alligators in the late 1970s to the current estimate of ≥130.
  • Only 23, 22, 20 and 32 Chinese Alligators were observed during spotlight count surveys in the ANNRCA in 1999, 2002, 2003 and 2005 respectively (Thorbjarnarson et al. 2002, Ding et al. 2004, Wu et al. 2008). Survey in 2005 indicated the total number to be around 92-114 individuals (Jiang et al. 2006, Wu et al. 2008), and that the wild population was stable in most sites and increasing in Hongxing, Zhucun, Zhuangtou and Heyi.
  • The most recent survey in 2015 indicated 64 individuals seen, of which 32 were adults, and the population was estimated at 136-173.
  • The population appeared to have stabilized between 1998 and 2003 (Ding et al. 2004), and increased slightly between 2003 and the present (Wu et al. 2008).
Inserting these estimates into the Red List Criterion A tool, declines of 89% in 35 years or 99% over three generations (75 years) are derived.
Current Population Trend:Stable
Additional data:
Number of mature individuals:68-86Continuing decline of mature individuals:Yes
Population severely fragmented:Yes
No. of subpopulations:13

Habitat and Ecology [top]

Habitat and Ecology:The Chinese Alligator is a relatively small crocodilian with a maximum length of approximately 2 m (Brazaitis 1973). The three principal habitat types where A. sinensis can now be found are:
  • remnant wetlands in low, broad, fertile valleys along main river courses, dominated by paddy fields;
  • intermediate ponds in low hill valleys (<100 m) but with significant agriculture in the valley above the pond; and,
  • ponds situated in low hill valleys (<100 m) at the upper edge of rice cultivation and the low edge of tree plantations (Ding et al. 2001, Thorbjarnarson et al. 2002, Watanabe et al. 1982).
Because they occur at relatively high northern latitude, Chinese Alligators spend a large portion of the year hibernating (aestivating) in subterranean burrows (Huang 1982, Huang and Watanabe 1986). The burrows can be complex, with above and below ground pools, and numerous air holes (Chen et al. 1985). The extensive use of these burrows and their very secretive behaviour has allowed A. sinensis to inhabit wetland habitats in areas with dense human populations.

Chinese Alligators usually begin to emerge from their dens to bask in May. In June, with warming temperatures, they will begin to make nocturnal sorties. Nesting occurs from early July to late August (Huang 1982), with 10-40 eggs being laid in a mound nest of decaying vegetation (Chen et al. 1985).
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:No
Generation Length (years):25
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: There is no current use or trade of wild specimens although traditional use for food, medicine and exhibits is supported from very large captive breeding programs in China.

Following a review of management and conservation of A. sinensis (Webb and Vernon 1992), in 1992 the ARCCAR facility was registered with CITES as a captive breeding operation. The primary intentions expressed at the time of registration were to provide alligators for local meat consumption and live animals for the European pet market. Income from the trade of captive-bred alligators was mainly used to maintain and continue captive breeding and conservation activities.

Threats [top]

Major Threat(s): The factors most responsible for the population decline have varied over the last 50 years, but have included habitat fragmentation and degradation, hunting, natural disasters (floods and drought), geographic separation, 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 the conservation of A. sinensis is habitat restoration as the first step towards reintroduction of captive-bred individuals. In addition, the potential consequences of environmental pollution and reduced genetic diversity of the wild population must be addressed (Ding et al. 2004).

Conservation Actions [top]

Conservation Actions: The Chinese Alligator is considered one of the world’s most endangered crocodilians. In 1972 the Chinese Government listed A. sinensis as a Class I endangered species, providing it with the highest degree of legal protection (Wan et al. 1998). Enforcement of regulations prohibiting the capture or killing of wild alligators, however, was not entirely effective, particularly during the 1970s and early 1980s (Watanabe 1982).

Since 1979, Chinese Alligator management focused on captive breeding, and centres were established in Anhui and Zhejiang Provinces (Wan et al. 1998). ARCCAR is the largest facility, housing over 10,000 A. sinensis and serving as the administrative centre for alligator management in Anhui Province. A 43,300 ha reserve for A. sinensis was established in Anhui Province in 1982 and promoted as the national nature reserve in 1986. From then on, the reserve, named the Anhui National Nature Reserve for Chinese Alligator (ANNRCA), covered a 5-county region and includes 13 protected sites that contained virtually all the remaining areas with wild Chinese Alligators.

Before 2000, the efforts for conservation of alligators in China mainly focused on the development of a number of rearing centres. ARCCAR was established in 1979 and stocked in 1981-82 with 212 wild individuals. Of these, 160-170 were still alive in 1990. Wild eggs (787 in total) were also collected between 1982 and 1985. Captive breeding has been very successful, with the first F2 produced in 1988 and the first F3 produced in 1998. By 2001 total stocks had reached 10,000 alligators with 700-1,000 hatchlings produced annually (Jiang et al. 2006), and by 2016 around 15,000 alligators were held at ARCCAR (Manolis et al. 2016).

A much smaller facility at Yinjiaban (Zhejiang Province), operated by the local cooperative, held 118 alligators
(2:2:114) in 1998. Since 2001, the centre has been managed by the Changxing Forestry Bureau, and has been re-named as the Changxing Chinese Alligator Nature Reserve (CCANR). By 2007, total stocks exceeded 630 alligators, with 100-200 hatchlings produced annually. In 2016, around 5500 Chinese Alligators were held in the original breeding centre and associated restored wetland habitats (Manolis et al. 2016).

Additional breeding centres have been established at Qiongshan City (Hainan Island), National Forest Park of Qiandaohu (Thousand Island Lake, Zhejiang Province) (Zhang 1994a,b), Doumen County (Guangdong Province) and Jiangying City (Jiangsu Province). In addition, some small-scale safari parks, museums and captive-breeding farms also rear A. sinensis (e.g., Chongqing and Shanghai Municipalities). Two private breeding farms have also been established at Wuhu (Anhui Province) and Nanjing (Jiangsu Province).

Captive breeding of Chinese Alligators has also been achieved at the Bronx Zoo (New York), St. Augustine Alligator Farm (Florida), and Rockefeller Refuge (Louisiana) in the United States. Specimens are held in zoos and private holdings outside of China, and studbooks are maintained for the USA and Europe (Jensch 2008).

To strengthen captive breeding and commerce management of crocodilians in China, the Guangzhou Advocation was issued at the International Workshop on Captive Breeding and Commerce Management in Crocodylia (Guangzhou, Guandong Province, China; 30 August-3 September 2001). This workshop also considered the deliberations of the International Workshop on Conservation and Reintroduction of Chinese Alligator (Hefei City, Anhui Province, China; 25-28 August 2001) (SFA 2002). To mitigate the pressure of the large captive population, the State Forestry Administration (SFA) of China funded $US 1.2 million and the Anhui Provincial Government co-financed about $US 0.74 million in 2003, which were provided for ARCCAR to construct two new breeding areas with the area of 1.6 ha, and reinforce the existing fence (length of 3,500 m to be more than 3 m high). All of these measures ensure good conditions for captive-bred alligators. Meanwhile, in 2003 the SFA provided $US 0.6 million and the Changxing Government co-financed $US 0.9 million for CCANR to facilitate infrastructure and wetland restoration. The Construction Programme for Releasing Chinese Alligators in Zhejiang Province was approved by the SFA in October 2006.

To effectively protect and manage the current wild Chinese Alligators and their habitats in Anhui Province, the State Council of China approved the range adjustment of the current ANNRCA to 18,565 ha, to benefit control of habitat destruction/alteration, reinforce the wild population, create habitat corridors for isolated sites, and mitigation of conflicts between natural protection and community development.
 
The Chinese Alligator is a good candidate for reintroduction because wild populations are at dangerously low levels and a large captive population exists. After the International Workshop on Conservation and Reintroduction of Chinese Alligator (SFA 2002), the SFA issued the “China Action Plan for Conservation and Introduction of Chinese Alligator” in 2002. Meanwhile, A. sinensis was also listed as the one of 15 priority species of National Wildlife Conservation Project in the Tenth-Five Year Plan. Since then, the Chinese Government has paid more attention to the protection and management of wild populations and their habitats, as well as speed up release projects. The ANNRCA initiated reintroductions in 2001. In 2003, three captive-reared alligators were released at one of the protected sites - Hongxing Reservoir. Monitoring results indicated successful breeding in 2004 and 2005 (Jiang et al. 2006). An additional reintroduction site, Gaojingmiao Forest Farm (GFF), was evaluated and identified as a reintroduction site by international and national crocodile experts in 2001 (Matsuda and Jenkins 2002). Over the last few years, a total of 50 ha of habitat has been reconstructed and restored. Since 2006, a total of 78 captive-reared alligators were released into different ponds at this site. On 22 July 2008, the first A. sinensis nest containing 19 eggs (17 of which were fertile) was discovered at GFF as ANNRCA staff were conducting regular patrols (Jiang 2008) and through 2015 a total of eight nests, 158 eggs and 80 live hatchlings were observed.

As part of a collaborative program between Shanghai Forestry Bureau, Chongming Dongtan Wetlands Company and the Wildlife Conservation Society (WCS), adult alligators were introduced into Dongtan Wetland Park in 2007 (N= 6; 3 surviving 2009) and 2015-16 (N= 6). Nesting was recorded in 2008, 2012, 2014 and 2015, and surveys undertaken in July 2016 indicate that the population comprises nine reintroduced adults, at least four adult progeny from the three alligators released in 2007, and up to five juveniles/sub-adults from nesting in 2012-2015 (Platt et al. 2016).

All of these cases indicate that captive-reared A. sinensis can adapt to restored habitats quickly and recover breeding capacity in the wild.

Citation: Jiang, H. & Wu, X. 2018. Alligator sinensis. The IUCN Red List of Threatened Species 2018: e.T867A3146005. . Downloaded on 20 July 2018.
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