By Benjamin Tapley, Andrew Cunningham, Samuel Turvey & Shu Chen, 24th February 2021
Chinese giant salamanders are the largest amphibians: they grow up to 1.8 m in length and can weigh over 50 kg. These impressive animals are considered global priorities for conservation on account of their ancient evolutionary history and global endangerment, which makes them EDGE species. The Chinese giant salamander is protected by Chinese law, but wild populations are in urgent need of protection as they are continuing to experience population declines. These declines are probably a result of habitat loss as well as overexploitation to supply a rapidly growing farming industry. Millions of giant salamanders are farmed in China. Although a proportion of farmed stock is released annually in local rivers as part of a government-endorsed conservation initiative, there is little evidence that these have resulted in the establishment of viable populations.
With our Chinese collaborators, we trialled and developed standardized techniques for ecological surveys of these amphibians, and for interview surveys conducted in local communities living near potential giant salamander habitat. Interview surveys are known to be an effective way of gaining new insights into the status and threats of economically and culturally significant species.
From 2013 to 2016 we spent 7.20 cumulative person-weeks of active searching and 7.33 person-years of passive searching, in what was probably the largest ever wildlife survey undertaken to date in China. During this time, we detected just 24 salamanders at four of the 97 sites we surveyed. We interviewed 2,872 people, of which 85.5 % recognized giant salamanders. However, the mean last sighting dated from approximately 19 years earlier.
We investigated the relative contribution of habitat loss and overexploitation in driving this range-wide decline of Chinese giant salamanders. We collected water parameters (temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, alkalinity, hardness and flow rate) from all 97 sites. We did not find any statistically significant differences between these parameters at sites where giant salamanders were found by our survey teams and/or had been recently seen by local people, and sites where they were not detected and/or from which they had recently disappeared. Alarmingly, we also found direct and indirect evidence that the poaching of giant salamanders from the wild is ongoing, including within protected areas. Our findings indicate that the decline of giant salamanders across China has been primarily driven by overexploitation.
The Chinese giant salamander was long thought to be a single species. However, our previously published research shows that it is actually composed of at least three distinct species, including the South China giant salamander Andrias sligoi. Conservation breeding programmes have been suggested as a necessary component of the conservation strategy for Chinese giant salamanders. Such programmes require a detailed understanding of the environmental requirements of the target species. Our water parameter data can be used to inform the management for Chinese giant salamander conservation breeding programmes in dedicated conservation breeding facilities in China. In fact, we have already successfully incorporated data collected from the field into the management protocols for Chinese giant salamanders in the reptile and amphibian house at ZSL London Zoo.
We hope that stakeholders and decision-makers in China will act upon our results, and will strengthen both in situ and ex situ conservation actions for giant salamanders while there is still time to save these remarkable species.
All photos: Benjamin Tapley/ZSL
The article Range-wide decline of Chinese giant salamanders Andrias spp. from suitable habitat is available in Oryx—The International Journal of Conservation.