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Status of Amphibians at the Zoige Wetlands, Sichuan Province, China

By Gary M. Fellers, Wang Yuezhao, and Liu Shaoyin DAPTF Seed Grant Holders 2002

(Source: http://www.open.ac.uk/daptf/froglog/FROGLOG-58-1.html)

We conducted field surveys for amphibians in 1997 and from 2000-2002 at the Xiaman National Conservation Region in the Zoige wetlands (90,000 km²). The wetlands are located at the headwaters of the Yellow River on the Qinghai-Tibetan plateau (32^o 20’ to 34^o 05’ latitude, 102^o 10’ to 103^o 55’ longitude) in the northern Sichuan province of China. The plateau has an average elevation of 3,450 m (11,320'), and the wetland encompasses two rivers and 14 lakes. Amphibians include one bufonid (Bufo minshanica) and two ranids (Rana chensinensis and Narorana pleskei).

Our population surveys showed a downward trend for all three species over the five-year span of our study. This decrease was most notable for Narorana, but was also apparent for both Bufo and Rana. The trend was not statistically significant due to the combination of the small number of sites and the variability in the count data.

In 2000, we initiated more extensive surveys and documented a significant decline in both the number of sites occupied and the maximum number of adult or subadult frogs recorded. Reproductive success (number of egg masses and/or number of tadpoles) varied by species. Bufo had modest numbers of egg masses, but we only recorded tadpoles in 2002. Narorana apparently did not reproduce at any of our sites during 2000 - 2002. We found a moderate number of Rana egg masses, but the number of tadpoles has been near zero since 2001.

The key question is why is this decline occurring? Frogs have occupied the Zoige wetlands for thousands of years, but the declines that we are currently seeing are not sustainable. In the last 10 years, there has been a general drying of the wetlands throughout the plateau with some wetland areas becoming sand dunes. The cause for this change is unknown. During the same period, the abundance and distribution of the three amphibian species has declined, even in areas that appear to have suitable habitat.

Many of the local naturalists have lived adjacent to the wetlands throughout their lives and are familiar with amphibians. These people report that 1) the Zoige wetlands were formerly far more extensive, 2) all three species of anurans were more widely distributed 10-20 years ago, and 3) amphibian populations have declined over the last 10 years (Zhang Ming and Liu Shaoyin, pers. obs.).

Yak and sheep grazing have taken place in this region for thousands of years. There have, however, been recent changes in the number of yaks and sheep, season of use, and areas grazed. There has also been an increased use of chemical fertilizers and pesticides. These changes may have resulted in changes to the wetland and meadow vegetation, a lowering of the water table or the conversion of wetland habitat to sand.

We must continue the current monitoring program for amphibian populations at Xiaman National Conservation Region so we can understand and document population trends.

Recommendations for future research:

Acknowledgements

Field work was conducted by Zhang Ming and Liu Shaoyin. Funding was provided by the Chengdu Institute of Biology, Academia Sinica; Chicago Zoological Society; the Declining Amphibian Populations Task Force; and the US Geological Survey.

Contact:

Gary M. Fellers, Western Ecological Research Center, USGS, Point Reyes National Seashore, Point Reyes, CA 94956 USA. Phone: 415-464-5185 gary_fellers@usgs.gov

Wang Yuezhao, Chengdu Institute of Biology, Academia Sinica, P.O. Box 416, Chengdu, Sichuan, The People’s Republic of China . arcib@cib.ac.cn

Liu Shaoyin, Sichuan Institute of Forest Protection, Sichuan Academy of Forest Sciences, Chengdu, Sichuan, The People’s Republic of China.

FROGLOG Number 58, August 2003