Applying Four Numerical Methods to Analyze Aquatic Insects Diversity In Rice Fields

From March 6 to June 5, 1998, aquatic insects were sampled from a biologically controlled rice field (B\^F\^) and a chemical controlled rice field (C\^F\^) in Dasha town, Sihui County, Guangdong Province, P.R. China. Forty_three species of aquatic insects were collected. Four numerical methods, Jaccards coefficient of similarity, coefficient of difference, values of global covering and coefficient of development, were used to evaluate the pollution. The result showed that fauna in B\^F\^ is different from those of C\^F\^ in species richness and abundance. It is suggested that coefficient of development and global covering be more reasonable to assess the water quality of rice fields.