The Effects of Tricyclazole Treatment on Aquatic Invertebrates in a Rice Paddy Field



The benthic macro-invertebrate community response to tricyclazole treatments in an experimental rice paddy field was analyzed using univariate and multivariate statistical analysis. The observed community presented low species diversity, dominated by the gastropods Gyraulus albus and Physa fontinalis, the oligochaetes Branchyura sowerbyi, and the hirudinea Alboglossiphonia heteroclita. No significant effect was detected following tricyclazole treatments, while a moderate shift in community composition was observed during the sampling period, with gastropods prevailing at the end of the experiment. Multivariate classification tree analysis emphasized the importance of sampling date over tricyclazole treatments. The limited period of submersion of the rice paddy field, the low oxygen content and the high water temperatures are supposed to be the reasons of the low community diversity observed.