Representing one of the largest hydropower-complex and flood control projects in the world, the Three Gorges Project (TGP) has been the key project for the improvement and development of the Yangtze River. Since its launch, any topic concerned the Three Gorges Reservoir (TGR) may become the public opinion focal point. In especial, its impact on the surrounding ecosystem has always been research hotspots.

However, there have been limited studies on the small mammal community inhabiting the beaches of Dongting Lake, which is located in the middle reaches of the Yangtze River, downstream of the TGR. These small mammals may be divided into 3 types-- the Norway rat and striped field mouse pest area and the Yangtze vole pest area. ALL species are not only able to cause major damage to crops, especially during outbreaks, but also serve as substantial reservoirs of human pathogens.

Aim at comparing the abundance of species in the small mammal community inhabiting the beaches of Dongting Lake before and after the TGP operation, and examining how the community structure and species composition have changed across 4 sampling periods that reflect different TGR water impoundment levels, researchers from the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) hypothesize that some species have expanded their inhabiting areas since the increase in beach exposure time after the TGP. That is to say, they try to investigate whether the regulation of water has caused the small mammal communities to relocate the beaches.

“We have spent a 20-year survey period to prove our hypothesis. And we use snap traps throughout the survey.”said ZHANG Meiwen, one of the main researchers, “our strenuous and long research indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam. First, species abundance on the beaches has increased. Second, dominant species concentration indices decline step by step. Third, the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches.”

Scientists suggest that a long-term project should be established to monitor the population fluctuations of the Yangtze vole, the striped field mouse and the Norway rat to safeguard against population outbreaks, which could cause crop damage to adjacent farmland, in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake.

The study entitled “Small mammal community succession on the beach of Dongting Lake, China after the Three Gorges Project”could be found at http://onlinelibrary.wiley.com/doi/10.1111/1749-4877.12073/abstract.

Scentists would like to send their sincere gratitude and appreciation to CHEN Anguo, a venerable old scientist in ISA for his helpful comments on a draft of this article and ZHANG Mingyang in ISA for her mapping out the sampling sites. Also many thanks should be given to the National Natural Science Foundation of China (30870402; 31170396; 51009129), Hunan Natural Science Foundation (14JJ2136) and the Chinese Academy of Sciences (KSCX-EW-N-05) for providing financial support for this study.