Abstract: The population dynamics of redents in Leizhou peninsula were st ud ied for forty years. During this period,the number of domestic rat Rattus flavipectus decreases and that of Rattus norvegicus and Mus musculus increases,which is connected with rodenticide and ecological environment deratization,and antirat measures in buildings should be strengthened. The number of wild rat Rattus rattoides decreases and that of Bandicata neumorivaga and Rattus rattus hainanicus increases,which may be related to the large scale planting of sugarcane. Rat-surveillance should be strengthened to take effective and practical measures for rat controlling.

Key words: earthworm cast, dissolved organic matter (DOM), heavy metal copper, ryegrass.