青弋江江滩植被与钉螺分布关系的初步研究

Preliminary study on relationship between vegetation attributes and distribution of Oncomelania hupensis on the beach of Qingyi River

目的研究江滩植被各属性与钉螺分布的关系。方法采用随机取样与系统抽样相结合方法,调查样方内植被的种类、株丛数、物候期、生活力、高度、盖度、多度和频度,钉螺的总螺数、活螺数、死螺数。结果江滩植被种类主要有12种,分别是空心莲子草、狗牙根、莎草、窃衣、野艾蒿、野菊花、苍耳、香附子、葎草、灯芯草、野大豆和辣蓼,其中空心莲子草和香附子为优势种群。空心莲子草群丛活螺最多(活螺密度为2.67个/0.1m2),狗牙根+辣蓼群丛死螺最高(死螺密度为2.33个/0.1m2)。将植被盖度和钉螺密度回归分析得二次函数y=11.435+2.104x-0.162x2(R2=0.394,F=42.319,P<0.01)(夏季)、y=14.154+1.034x-0.043x2(R2=0.794,F=57.432,P<0.01)(秋季)。结论钉螺对空心莲子草群丛有趋向性,狗牙根+辣蓼群丛可能有杀灭钉螺的作用,植被盖度和钉螺密度是平滑的二次函数关系。

Objective To study the relationship between vegetation attributes and distribution of Oncomelania hupensis on the beach of Qingyi River. Methods Using a combination of random sampling and systematic sampling, an investigation was conducted on the vegetation and O. hupensis in the quadrats on the beach of Qingyi River to determine the species, cluster number, phenological period, viability, height, coverage, abundance, and frequency of vegetation as well as the total number of snails, number of living snails, and number of dead snails. Results There were 12 major species of vegetation on the river beach, including Alternanthera philoxeroides, Cynodon dactylon （Linn.） Pers., Cyperus microiria, Torilis scabra （ThuMb.） DC., Artemisia lavandulaefolia DC., Dendranthema indicum （L.） Des Moul., Xanthium sibiricum, Rhizoma cyperi, Humulus scandens （Lout.） Merr., Juncus effusus, Glycine soja Sieb. et Zucc., and Polygonum flaccidum Meissn.; A. philoxeroides and Rhizoma cyperi were the dominant species. The density of living snails was the highest in the A. philoxeroides cluster （2.67 living snails/0.1 m2）, and the density of dead snails was the highest in the C. dactylon/P, flaccidum cluster （2.33 dead snails/0.1 m2）. The regression analysis of vegetation coverage and O. hupensis density produced the following quadratic functions： y= 11.435 ＋ 2.104x -- 0.162x2 （R2=0.394, F=42.319, P〈0.01） （summer）; y=14.154 ＋ 1.034x -- 0.043x2 （R2=0.794, F=57.432, P〈0.01） （autumn）. Conclusion O. hupensis has a tendency toward the A. philoxeroides cluster, and the C. dactylon/P, flaccidum cluster may have a molluscicidal effect on O. hupensis. The relationship between coverage of vegetation and density of O. hupensis can be reflected by quadratic functions.