滩地抑螺防病林对钉螺孽生的影响

发布时间：2018-06-02 01:10

本文选题：钉螺 + 滩地　；参考：《西南大学》2010年硕士论文

【摘要】： 滩地是平原河床季节性淹水的微地形,主要的生境特点是冬陆夏水。长江中下游滩地面积约为6.3×105hm2,可利用程度大。“八五”以来,采取“以林为主”的生物工程措施对滩地进行了综合治理与开发,一方面充分利用了滩地的土地资源,一方面采用复合经营方式改变了滩地的原生环境,使得生物群落格局发生变化,同时也营造了不同的林内小气候,为防治吸血虫病开创了新的途径。在原生滩地上,钉螺繁殖生长基本属于自然状态。其死亡除了植物性食物影响外,主要还受气候因子的制约。前者是相对稳定的因子,其食物主要包括藻类、苔藓、蕨类和草本种子植物,而后者则随时空变化较大。杨树是滩地抑螺防病林的主要用材林树种,研究不同林龄与经营模式抑螺防病林下草本植物层的特征结构、钉螺死亡率与林分小气候因子间,钉螺死亡同钉螺体内糖原含量变化与林下土壤物理化学性质之间的相关规律,对探索钉螺种群的消长规律及其与滩地生态系统的关系具有实际指导意义。本研究时间区间选择5月26日-7月16日,通过野外林学调查和土壤样品采集,根据2009年钉螺的生长旺盛期所测得的实测数据及便携式自动气象站观测的气象资料,运用方差分析和逐步回归分析等统计方法,确定水热环境参数,建立钉螺累积死亡率与小气候因子关系模型,比较不同植被类型草本层结果特征,钉螺生存对主要生活土壤物理化学性质变化的响应差异,并最终通过主成分分析和聚类分析方法对黄州滩地监测样地的环境抑螺效果进行评价,以期为滩地环境监测以及血吸虫病的防治提供重要信息和科学依据。试验结果表明： (1)三年生间种模式钉螺死亡率最高,然后是曾经有过4年间种历史的5年生纯林地,接着是一年生林药混种林,3年生、1年生纯林,最后是有过4年间种历史的8年生纯林地和原生滩地。 (2)毁芦造林打破了滩地原来的单优势种群落结构,植物物种数增加,群落平均盖度增加,植被平均高度下降,均匀度指数提高。杨树人工林使原优势种飞蓬、芦苇等的重要值下降,随着林龄增加,耐荫草本增加喜光草本减少,木本科草本增加禾本科草本减少,生境朝着中生化方向发展。滩地造林,除8年生纯林外,明显增加草本植物群落的平均盖度、Shannon-Wiener指数、均匀度指数和：Simpson指数,物种多样性增加。 (3)影响钉螺累积死亡率的主导气候因子分别为土壤5-10cm湿度和土壤0-5cm温度。小气候因子间是相互影响、相互制约、共同作用的,并通过单优势性、协同作用、共同作用、拮抗作用等形式对钉螺死亡率产生直接和间接作用。 (4)试验以林代芦,建立滩地林农生态系统后,8种类型土壤物理性质的方差分析结果不显著,土壤化学性质之间存在显著差异。土壤全氮含量和土壤容重与土壤总孔隙度是影响钉螺死亡率的最重要的3个因子,前者与钉螺死亡率呈正相关,后二者则成负相关。土壤容重由于总孔隙度是通过容重计算而得,故以全氮和容重2个因子作为反映土壤是否适宜钉螺孽生的指标更简单、实用；另外,仅土壤速效钾含量对钉螺体内糖原含量影响显著且成负相关。 (5)采用主成分分析和聚类分析,对黄洲长江外滩7个典型抑螺防病林8个指标进行分析,提取出3个主成分。应用分层聚类分析法对该3个主成分的因子得分进行聚类,在此基础上,将主成分得分与其对应的特征值相乘,得到环境抑螺效果评价指数。聚类分析后样地划分为4类,取其平均值对每一类确定抑螺效果等级,得出3年生杨树纯林与油茶间种的复合林抑螺效果最为明显,而1年生的杨树纯林同1年生杨树与小麦的林农复合林2者环境抑螺效果最低。
[Abstract]:On the one hand , the biological engineering measures in the middle and lower reaches of the Yangtze River are mainly composed of algae , moss , fern and grass seed plants .

By means of field forest survey and soil sample collection , based on the measured data and meteorological data observed by the portable automatic weather station in 2009 , this paper uses the statistical methods such as variance analysis and stepwise regression analysis to determine the water thermal environment parameters , establishes the relationship model between the cumulative mortality rate and the small climatic factor of the main living soil , compares the results of different vegetation types , and provides important information and scientific basis for the monitoring of the beach environment and the prevention and control of schistosomiasis . The results show that :

( 1 ) The highest rate of snail mortality among three - year - old is followed by five - year - old pure forest land , which once existed for 4 years , followed by annual forest - drug mixed forest , three - year - old and one - year - old pure forest , and finally , eight years of pure forest land and native beach in four years .

( 2 ) The destruction of the forest has broken the original single dominant population structure , the number of plant species increased , the average cover degree of the community increased , the average height of the vegetation decreased , and the evenness index increased .

( 3 ) The dominant climatic factors that affect the cumulative mortality rate of Onononensis are 5 - 10cm soil moisture and 0 - 5cm soil respectively .

( 4 ) The results of variance analysis of 8 types of soil physical properties were not significant and there was a significant difference between soil chemical properties . The total nitrogen content of soil and total soil porosity were the most important factors affecting the mortality of snails .
In addition , only the content of available potassium in soil had a significant negative correlation with the content of glycogen in the snails .

( 5 ) According to the principal component analysis and cluster analysis , the eight indexes of 7 typical snail control diseases in Huangzhou Yangtze River were analyzed and three main components were extracted . Based on the results , the main component scores were multiplied by the corresponding characteristic values to obtain the evaluation index of the environmental inhibition effect .
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R184

【参考文献】