Effects of the Three Gorges project and change of water level on local mouse density / 中国地方病学杂志

ABSTRACT

Objective To study the impacts of the Three Gorges dam and change of water level on the survival of the local rodents, and to provide scientific basis to control the outbreak of rodent-borne diseases.Methods Four villages located around the Three Gorges dam were selected in the study. The mouse populations by using Elton night trapping method was monitored. Metallic spring traps were set for two consecutive nights. The mouse density and identified the mouse species was calculated. The mouse species indoor and outdoor, as well as the mouse density indoor and outdoor were compared. The impacts of water level in the dam and cleaning work on local mouse density were also analyzed. Results A total of 678 mice were caught in this study, 517 were caught indoor and 161 outdoor. Indoor dominant species was flavipectus; accounting for 36.49%(189/517), while outdoor was apodemus, reaching 56.88% (91/161). For mouse species, there was a significant difference between indoor and outdoor(x2 = 678.00, P ＜ 0.01 ). The average mouse density was 8.44%(678/8036) in trap nights. Indoor mouse density reached 14.44%(517/3581 ), which was significantly higher than that of outdoor(3.61%, 161/4455 ).For mouse density, there was a significant difference between indoor and outdoor(x2 = 301.04, P ＜ 0.01 ). When the water level was up to 156 m, mouse density reached 10%(513/5132), which was higher than that of before (5.68%, 165/2904). There was a significant difference in mouse density before and after reserving water (x2 = 44.68, P ＜ 0.01 ). With the change of water level, upstream mouse density formed a high platform from May 2007 to May 2008, followed by 12.25%(80/653), 13.16%(90/684), 12.95%(90/695), and decreased to 8.38%(28/334) after cleaning of the dam. Conclusions The Three Gorges dam and change of water level actually alter the survival environment of the local mouse, and affect local mouse density and mouse species. These may lead to local outbreak or epidemic of rodent-borne diseases.