基于植物多样性的银川平原灌排系统生态效应

在对银川平原各级沟渠体系进行植物群落调查的基础上,计算了各级沟渠湿地的4个常用的植物多样性指数,即Margalef指数、Simpson指数、Shannon-Wiener指数、Pielou指数,并分析了不同灌排水系植物多样性与水文、水利工程因素的关系。结果表明:Margalef物种丰富度指数和Shannon-Wiener物种多样性指数对植物多样性的表征意义比较显著;各级排水沟的生物多样性指数普遍比各级灌渠大,生态效应较好。在综合考虑节水和生态双重效益的前提下,应当采取干支渠全面砌护、斗渠减少砌护、农渠毛渠不砌护的生态水工策略。还可采取适当减缓沟渠迎水坡坡度,加长坡面,或者采取阶梯状边坡筑建模式,以及拉长排灌水系的修整间隔时间等措施。

Ecological Effects Based on Plant Diversity for Irrigation-Drainage System in Yinchuan Plain

Based on the plant community investigation on all levels canals in Yinchuan Plain,this paper calculated four often used plant diversity indices of all levels canals and everglades such as Margalef index,Simpson index,Shannon-Wiener index and Pielou index.The paper also analyzed the relations among the plant diversity,hydrological and hydraulic projects under the different irrigation-drainage system.The results show that both of the Margalef species richness index and the Shannon-Wiener species diversity index have distinct token signification in terms of plant diversity.The plant diversity indices of all levels of drain ditches are popular higher than all levels of irrigation ditches and as well as better ecological effects.Based on an overall consideration of double benefits in terms of saving water and ecology,the following hydraulic strategies should be taken : the main and branch canals should be built and protected in an all round way,the building and protection of lateral canals should be reduced and the other smaller scale ditches should not be built and protected.Appropriate measures include decreasing the grade of ditch slope witch move towards water and extending the side of slope also be adopted.Other ways such as using model of ladder shape slope and delaying the using-time of irrigation-drainage System also can be taken.