【摘要】 对影响洞庭湖滩地杨树人工林生态系统钉螺分布密度的主导水分因子和钉螺分布密度的时空变化规律进行了定位观测研究。结果表明:钉螺分布密度与汛期淹水时间、地下水位、土壤含水率有关,表现为地下水位>土壤含水率>淹水时间;地下水位随滩地高程、林龄的增加或湖水水位的降低而降低,秋冬季地下水位常低于春季;土壤含水率在多阴雨的春季常高于秋冬季,并随滩地高程的降低、地下水位的升高而增加;钉螺活螺框出现率和活螺密度均随高程的升高、林龄的增加或地下水位的降低而降低;挖沟抬垄整地所形成的杨树林分林内微生境的活螺框出现率与活螺密度大小为垄面<保留带<沟壁坡面、沟底<芦苇地(对照)。更多还原

【Abstract】 Based on oriental observing on the poplar plantation eco-system in Dongting Lake’s beaches,the time-space changing regularity of dominant water factors and snail distribution density had been studied quantitatively in this paper.The main results were as follows.Firstly,snail distribution density had a bearing on submerging time in flood season,groundwater level and soil water content.Moreover,the order of these factors’ dominance was groundwater level,soil water content and submerging time.Secondly,groundwater level would be dropping with elevation raising,plantation getting older or Dongting Lake’s water level decreasing;and it was always lower in autumn and winter than in spring.However,soil water content was always higher in spring than in autumn and winter,and would be increasing with elevation dropping or groundwater level going up.Similarity to groundwater level,the occurring rate and density of surviving snail would also be dropping with elevation raising,plantation getting older or Dongting Lake’s water level decreasing.Different microhabitats which were taken form by digging ditches and making into ridges in poplar plantation had different occurring rate and density of surviving snail;and they were in the ascending sequence of ridge faces,retaining zones,ditch walls or bottom,and Phragmites communis sites(contrast).更多还原