Arthropod biodiversity and community structure as influenced by different winter-cropping systems in the paddy fields of Enping City, Guangdong Province

In order to assess the dynamics of arthropod biodiversity and community structure in a typical winter paddy field, investigations were carried out in 5 typical cropping systems, including early-rice-late-rice-winter-potato (RRP), rice-rice-winter-vegetable (RRV), rice-rice-winter-fallow (WF), field-ridge rice-rice-winter-fallow (FR) and rice-rice-winter-turnover-plow (PF) during the winter of 2005～2007 in 12 townships of Enping City, South China. Results for the winter of 2005～2006 show that spider is the dominant arthropod species in the 5 plots, while lepidoptera dominates in RRV treatment. Biodiversity index is significantly different (P＜0.05) among the 5 treatments. The indexes of richness eveness (DG) and density (J) in RRV and RRP treatments are higher than the other three. Shannon-Wiener diversity indexes (H) in FR and RRV treatments are 1.865 9±0.103 7 and 1.590 9±0.093 8 respectively, which are higher than the other treatments. The highest densitygroup index (DG) is 7.595 0±0.047 6, existing in RRV treatment. Results for 2006～2007 are similar to those for 2005～2006. RRV and FR treatments have higher H 1.782 5±0.145 4 and 1.137 9±0.101 5，than the others. The highest diversitygroup index (DG) is 11.210 3±0.351 2 in RRV treatment. Sorenson similarity index (S₁) is highest between WF and RRP treatments, while PF and FR treatments have low S₁. Whittaker similarity index S₂ between FR and RRP treatments is the highest, while RRV and RRP treatments have the lowest. In conclusion therefore, biodiversity of winter-turnover-plow (PF) is significantly different from the other cropping systems, and ricericewintervegetable (RRV) system has a significant effect on biodiversity enhancement in paddy fields.