关键词: 濒危物种保护, 野外调查, 种群大小, 致危因素, 保护计划

Abstract

Aims: In order to support conservation efforts for the endangered Jiangxi giant salamander, we conducted a comprehensive long-term field monitoring project to assess population dynamics, species distribution, and potential threats to the species. The findings from this study will serve as crucial guidance for the development and implementation of conservation initiatives for this endangered species.

Methods: In this study we established long-term monitoring of both population ecology and habitat of the wild population of the Jiangxi giant salamander (Andrias jiangxiensis) in the Jinjia tributary of the Beiliao River between 2021 to 2023. The population status was evaluated using the mark-and-recapture method which allowed us to gather essential data on population characteristics, life history, habitat condition.

Results: A total of 628 adult and juvenile Jiangxi giant salamanders were successfully captured. Among them, 543 were tagged with passive integrated transponder (PIT) tags, and 230 were recaptured at least once. Using the Schnabel model for estimating population size from mark-and-recapture, the population size was estimated to be 474 individuals (95% CI: 427–534). The calculated population density was 79 individuals/km (95% CI: 71–89) or 1.31 individuals/100 m² (95% CI: 1.19–1.48). An analysis of population structure indicated that few individuals had a body size smaller than 30 cm or larger than 70 cm. During the three consecutive years of 2021 to 2023, a total of 738 larvae were observed between January and March, a time of the year when the newly hatched larvae swim out of their breeding cave and begin to forage. In contrast, only 12 larvae were seen across the whole habitat range between April and December, with an extremely low catch per unit effort (CPUE) (0.38 individuals/person·hour). Our observations indicate that larvae of the Jiangxi giant salamander face challenges from both predators and environmental factors, leading to a low survival rate in their natural habitat. Habitat assessments have revealed significant threats to the isolated population of this species, including environmental fluctuations such as floods and perturbations of water flow, which pose a risk to their survival.

Conclusion: This study recommends the evaluation of the Jiangxi giant salamander as Critically Endangered (CR) and a National Class I Protected species. Consequently, we urge the implementation of specific conservation actions.

Key words: endangered species conservation, field survey, population size, population status, assessment