Dynamics and Species Composition of Field Rodents
in Yunlin and Chiayi Area (2004-2008)
Chen, S. K. and J. C. Hung
The population density and species composition of field rodents were investigated between 2004-2008. In Yunlin county, the density before control was fairly stable and even increased mildly after control (from 2004-2007), but in 2008, the population dramatically decreased both before and after control. In Chiayi county, the population rose both before and after control between 2004-2007 while the density declined slightly in 2008. The multiple rate was 4.7 times in Yunlin and 5.5 times in Chiayi. The control efficiency decreased in both counties. The average control efficiency was 75.9% in Yunlin and 76.3% in Chiayi for 5 years. In terms of the species composition, the major species captured were Rattus losea, Apodemus agrarius, Bandicota indica, and Mus formosanus, while Rattus norvegicus was only trapped once. Rattus losea and Apodemus agrarius were dominant species and more individuals of these two species (Rattus losea 22-72%; Apodemus agrarius 12-70%) were found than the other species before and after the control. Rattus losea had a greater population than Apodemus agrarius after control. The overall population of Bandicota indica was very stable and the rate generally increased after control. Mus formosanus had a relative unstable population after the control and its population rate decreased greatly after control.
Key words: Field Rodents, Population Density,
Accepted for publish: May 21, 2012