崇明岛稻田三种种植方式下中小型土壤动物群落多样性

平陆运河是西部陆海新通道的一项重要工程，茅尾海是平陆运河的重要支撑节点。本次调查潮间带大型底栖动物群落，在评估茅尾海生态环境质量的同时，又积累本海域大型底栖动物基线数据，为平陆运河建设期、运营期的科学管理提供科学数据支撑。于2020年10月和2021年1月、4月、7月，在钦州茅尾海东部岸线设置4个采样断面，分别是仙岛公园、沙环村、滨海公园和康王庙村，按照《海洋调查规范》(GB 12763.6-2007)的要求对潮间带大型底栖动物进行采样调查和物种分类鉴定；分析大型底栖动物群落组成、优势种组成及生物多样性指数。调查研究结果表明，茅尾海潮间带大型底栖动物以节肢动物为主，物种占比超过41%，个体数占比超过87%，优势种(IRI > 1 000)有麦克碟尾虫(Discapseudes mackiei)、台湾泥蟹(Ilyoplax formosensis)、隆背大眼蟹(Macrophthalmus convexus)和四齿大额蟹(Metopograpsus quadridentatus)，但优势种在4个断面分布不均，仅麦克碟尾虫出现在各断面；主要种(100 ≤ IRI < 1 000)有27种，其中仅扁平拟闭口蟹(Paracleistostoma depressum)、背毛小头虫(Notodasus sp.)出现在各断面；常见种(10 ≤ IRI < 100)有19种，稀有种(IRI < 10)有8种，它们均分布不均；辛普森多样性指数(D)和香农多样性指数(H?)分别为0.435(0.183 ~ 0.704)和1.506(0.747 ~ 2.256)，显著低于2009年相应指标，P值分别为0.004和0.048；Pielou均匀度指数(J)均值为0.475(0.223 ~ 0.696)，与2009年的Pielou均匀度指数(J)没有显著差异(P = 0.109)。综合丰度-生物量曲线(ABC曲线)、香农多样性指数(H?)、大型底栖动物污染指数(IMP)推断茅尾海目前整体海域生态环境处于中等污染水平。综合上述指标，认为目前茅尾海海域整体生态环境已属于中等程度污染。本次调查建立的茅尾海潮间带大型底栖动物数据库，将为未来平陆运河的生态建设和科学运营提供支撑。

Diversity of Small and Medium-Sized Soil Animal Communities in Paddy Fields Under Different Rice Planting Patterns in Chongming Island, China

Objectives] Small and medium-sized soil animals are important components of soil fauna in terrestrial ecosystems. Research shows that there are many biotic and abiotic factors that affect soil fauna diversity in anthropogenic ecosystems such as paddy fields, and anthropogenic disturbance factors such as planting methods play the most obvious role. Chongming Island is an important agricultural planting area in Shanghai. The influence on ecosystem of rice farming is the focus in the rice production process. At present, although there have been some reports on the community structure and diversity characteristics of soil animals in paddy fields under different planting methods, these studies have not yet covered the three rice planting methods of conventional, organic and ecological (rice-fishing) in the same area. Therefore, the present study investigated the differences in the diversity of small and medium-sized soil animals under three rice cultivation methods. Methods] This study set up three sample plots, which are all located on Chongming Island. The three plots are mainly cultivated with rice, and their natural vegetation and production background are basically the same. Their farming patterns were conventional planting, organic planting and ecological planting (Table 1). According to different rice growth stages, this study investigated the small and medium-sized soil animals in paddy fields in January, March, June and October, 2020, with a total of 4 samples. Small and medium-sized soil animals were separated by Tullgren method, and one-way ANOVA and Kruskal-Wallis H method were used to test the significance of differences. Results] The results showed that a total of 449 small and medium-sized soil animals were obtained, belonging to 2 phyla, 5 classes, and 8 orders (Table 2). The dominant group was Collembola, accounting for 82.18% of the total catch. Among the three planting methods, Symphyla are only found in the soil of conventional paddy fields, Rosette is only found in the soil of organic paddy fields, and Hemiptera and Orthoptera are only found in the soil of ecological paddy fields. The community structure of small and medium-sized soil animals were significantly different in paddy fields under three planting methods, the density difference of small and medium-sized soil animals in different plots were significant, and the density of organic paddy fields was higher than the others (Fig. 1). The vertical distribution of small and medium-sized soil animal communities showed surface clustering characteristics, and the number and density of groups showed a downward trend (Fig. 2). There was no significant difference in the number of groups of small and medium-sized soil animals in different soil plots. The richness index, diversity index, and evenness index of small and medium-sized soil animals in ecological planting paddy fields were the highest, and the dominance index of organic planting paddy fields was the highest (Fig. 3). Three different planting patterns showed moderate similarity between any two groups. Conclusion] Compared with conventional and organic planting patterns, ecological planting pattern is more conducive to improving the diversity and evenness of small and medium-sized soil animals and promoting the stability and healthy development of the paddy ecosystem. It is of significance to the sustainability of rice planting and as the indicator of agricultural non-point source pollution. At the same time, there are many factors affecting the community structure of small and medium-sized soil fauna in paddy fields, we suggest that further studies can be performed with the correlation among climate factors, physical and chemical indexes, and soil fauna community.