【作者】 蒋俊明；

【导师】 彭镇华；

【作者基本信息】 中国林业科学研究院 ， 森林培育， 2013， 博士

【摘要】 本论文根据山丘区地形、地貌及社会经济特点，以各立地钉螺密度调查和生境因子测试数据为基础，研究了山丘型疫区钉螺分布规律及生态位属性；采用室内实验法检测了四川疫区13种植物材料的灭螺效果；通过对比法研究了抑螺防病林替代钉螺适宜草本群落后，各生境因子的变化，探讨山丘型疫区植物抑制钉螺的机理，为目前实施的林业血防工程提供相关树种选择、优化模式和结构配置的技术。研究的主要结果：（1）山丘地区各台地和各生境类型均有钉螺分布，但重点分布于沟边、田边、林缘等水陆交错带，具点状和线状分布特征。钉螺密度（只/0.11m2））大小排序：水田（7.32）>沟渠（6.25）>荒草坡(5.71)>河滩(3.62)>旱地（1.29）>林地（0.12）。（2）钉螺适宜的草本群落的物种丰富度为4～14、盖度为70%～90%、高度为20-～50cm；适宜的土壤湿度在毛管含水量附近，具体范围因土壤类型和结构各异；适宜温度介于15～30℃，电导率介于60～120mS/m。（3）连接性量化分析结果表明：苔草、金星蕨、凤尾蕨等对钉螺具有排斥作用，而葎草、碎米荠、五朵云、拉拉藤、通泉草、水金凤等对钉螺具有庇护作用的植物可作为钉螺指示种。（4）桉树成林后，林下植被种类稀少，仅存一些禾本科草本和蕨类植物，慈竹林郁闭后，地面几乎没有任何草本存在，据此推断草本层的消失是森林发挥抑螺效应的主要原因之一。（5）林内空气湿度与草丛内差异较大，在晴天中午（14：00时）竹林内空气湿度为43.30%，而草丛内仍维持在60.30%以上，即成林后，草本层的消失，使钉螺暴露于干燥环境中；使之失去适宜的生存条件，这或是钉螺适宜于草丛内的原因之一；仅从数量上看，成林后，林木对温度、光照直接作用不明显，但间接影响（即森林生态系统建立后，乔木层通过减弱林内光强和光质，进而影响钉螺所依存的草本群落）是调节草本群落组成、盖度等实现。（6）造林后，桉树和竹林自身固水量可达32.65-178.51T/hm2，丰产培育的竹林每年因采伐带出系统的水分量可达24.9T/hm2，约占年降雨量的0.25%左右；林冠截留量占降雨量11%～40%；林木蒸腾耗水量较原有草滩至少增加了20%～40%；加之造林后对土壤入渗能力的改善，减少了地表的积水，据此计算：进入林地的水分数量较草滩（荒草地）少30%或更多；实测结果也证明竹林地表层土壤水分）较对照（滩地）低4.08%～11.57%；加之草滩变为林地后，土壤结构得到了改善，进而改善表土的入渗能力，使表层水分更易向深层土壤转移，减少了地表积水面积，进而降低地表水分储量，达到压缩了钉螺适宜空间的目的。（7）随林分郁闭度地增加，地表逐年被树叶、树枝、竹叶等枯落物覆盖，最终替代了原有的草本层，枯落物及其分解产物不仅抑制草本萌发与生长，同时也对钉螺的运动、取食、所需的光照等产生负面影响，调查结果表明枯落物覆盖下的钉螺壳色较淡、部分呈变白，死螺数量增加。（8）据LC50值的大小分组，桉树叶、臭椿叶、香樟叶归为剧毒组，其值小于0.1ppm；核桃叶、香根草根、桔叶为强毒组，LC50值介于0.2～1.0ppm之间；香根草叶、苦楝、花椒叶、夹竹桃叶、桔皮为毒性组，值介于1.0～5.0ppm之间，枫杨和生姜枝有毒组，值介于10.0～20.0ppm之间。主要创新点：（1）论证了指示植物作为钉螺生境识别和评价指标合理性和科学性。（2）桉树、臭椿、香根草等优良植物材料的筛选，为植物灭螺剂的研制提供了最具潜力的素材；（3）首次揭示了山丘型疫区林木的控螺机制。更多还原

【Abstract】 In this paper, considering characteristics of social economic,landform and physiognomyin hilly areas, we mainly focused on the distribution, ecological niche by investigatingOncomelania snail （hereafter referred to as snail）and testing habitat factors，as well as forestclimate, soil moisture and litter accumulation. The effects of controlling snail for13kinds ofplant materials are tested with indoor experimental method. These studies intended to revealthe mechanism of forest plantation on snail control and schistosomiasis prevention and toprovide technical supports for schistosomiasis-control in hilly area.The main results as follows:(1) Field investigation showed that snails are widely distributed in various land use typesin hilly region, but mainly in acetone area such as ditches, field edge with a punctuate andlinear pattern. The population density of snail per0.11m2were that paddy (7.32)> ditch(6.25)> barren grassland (5.71)> river beach land (3.62)> dry land (1.29)>woodland (0.12).(2) My investigation showed that the suitable herbaceous species richness for snail was4～14, the suitable herb community coverage was70%～90%, the suitable plant height was20～50cm; the most suitable soil moisture was nearby the capillary water; the suitabletemperature range was between15～30℃, suitable conductivity was between60～120mS/m.(3) By the quantitative analysis of connectivity，those plants with moss, Parathelypterisglanduligera, Pteris multifida are negative for snail distribution, and Humulus japonicas,Cardamine hirsute, EupHorbia helioscopia, Galium aparine, Mazus japonicas, Ranunculusjaponicas, Impatiens noli-tangere were positive species, which are be used as indicator forsnail habitat.(4) Understory vegetation types were scarce in Eucalyptus forest, and only few herbs andferns existed, hardly any ground herbs is in bamboo forest stand. According to thephenomenon，the conclusion that the disappearance of the herb layer is one of the main reasonsof controlling snail by forest. (5)Results of the routine meteorological factor showed that air humidity inside the forestand grass was different, and the maximum difference value was more than20%: air humidity(14:00) in bamboo forest was43.30%, but it was60.30%in grassland. Maybe this is one of thereason why herb layer was suitable for snail survival. After forest plantation, the directinfluence of changes of temperature and light for snail is less, but the indirect impact isbigger by adjusting coverage and species of herb.(6) Two forest stands with Eucalyptus and Bamboo can save water content up to32.65-178.51T/hm2in their body; water loss was up to24.9T/hm2in high yield cultivation ofbamboo every year, and it was about0.25%of annual rainfall. The canopy can intercept11%～40%of the rainfall. Rainfal interception proportion by canopys of five stands inchangning (Pleioblastus amarus, Cunninghamia lanceolata, phyllostachys pubescens,Dendrocalamus membramaceus and oak forest) were among21%～32%; After afforestation,forest transpiration was20%～40%more than the original marsh, together with theimprovement on soil infiltration capacity, forest made water infiltrate into deeper soil mor andreduced hydrcele in the soil surface. As a result, the total forest water input reduced30%ormore than that into woodland. Experimental result also showed that soil moisture in0～20cmsoil layer was0.5%lower in Eucalyptus plantation, and it was4.08%～11.57%lower inbamboo grove. Forest plantation mostly affected soil water content, which showed thatafforestation improved soil texture and soil infiltration condition and made water transferringfrom surface to deep soil easier, and this reduced soil surface water storage and result in acompression of the snail suitable space.(7) After planting, forest litters accumulated on soil surface, and the litters replaced theoriginal herb layer. The litter fall and decomposition not only inhibited the germination andgrowth of herbs, but also negatively affected snail movement, and acquirement for food andlight. Experimental results showed that snail density was correlated with litter thickness andcoverage, and snail was weak with pale shell and has high mortality.(8) Main plant materials in experimental zone had very good molluscicidal effect. alcoholextract of Eucalyptus leaves, Ailanthus altissima and camphor has highly toxic group, and the LC50was lower than0.1ppm.Walnut, vetiver and orange were also with molluscicidal effect,the LC50value was between0.2-1.0ppm; Vetiver grass, Melia azedarach, pepper leaf,Oleander Leaf, orange peel were also with toxicity, the LC50value was between1.0-5.0ppm;the LC50value was between10.0-20.0ppm for Wingnut and ginger shoots.Main innovations are as follows:(1) The rationality that indicator plant is named as index of recognizing and evaluatingsnail habitat. is demonstrated.(2) The plants with eucalyptus,ailanthus and vetiver are selected provide the mostpotential material for developing plant molluscacide.(3) For the first time, the mechanism of controlling snail by forest is revealed.更多还原