三峡工程和退田还湖对洞庭湖区东方田鼠种群的潜在影响

Possible impacts of the Three Gorges Project and converting farmland into lake on the Microtus fortis population in Dongting Lake region

洞庭湖东方田鼠种群的暴发成灾与洲滩演替关系密切.湖泊泥沙淤积导致湖滩面积增加,大面积的湖滩为东方田鼠种群增长提供了重要基础;而围湖造田、为根除血吸虫病而围湖灭螺以及滥捕天敌是湖区东方田鼠20世纪70年代开始形成严重危害的直接原因.近些年实施的三峡工程和退田还湖会对洞庭湖环境产生深远的影响.三峡水库蓄水后对长江中下游水量的调节将导致洞庭湖中低位洲滩出露面积的增大,退田还湖的实施亦将直接增加湖滩面积,这都将会扩大东方田鼠潜在的栖息地,会使东方田鼠种群进一步增长.因此必须高度关注东方田鼠未来种群的数量变化趋势.

The outbreak of Yantze vole（Microtus fortis） population in Dongting Lake region is closely related to the evolvement of lake beaches,because the deposition of lake sediments results in the expansion of lake beaches,which provides the possibility of the increase of the vole＇s population.Reclaiming farmland from lake via building cofferdams,eliminating snails by building cofferdams for eradicating schistosomiasis,and over-hunting predators in the region cause the voles becoming a pest after the 1970s.In recent years,the Three Gorges Project and the conversion from farmland into lake have had deep impacts on the environment in the Lake region.The dispatching of the down flow rate by the Project induces the expansion of the low and medium level beaches in the Lake region,while converting farmland into lake directly induces the increase of beach area,both of which expand the potential habitats of the vole＇s population.Therefore,more attention should be paid on the quantitative variation trend of the vole＇s population in the future.