稻蟹共作对稻田水体底栖动物多样性的影响

稻蟹共作是一种生态型种养新模式,而底栖动物是该复合生态系统的重要组成部分。为研究稻蟹共作对稻田底栖动物多样性的影响,在水稻分蘖期、拔节期、扬花期和成熟期,采集不同放养密度的稻蟹共作稻田(仔蟹放养密度10 ind.m 2,低密度,LD;仔蟹放养密度30 ind.m 2,高密度,HD)和常规稻田(不放蟹,常规栽培,CK)水体的底栖动物,分析不同稻田生态系统底栖动物的种类构成、密度和多样性。结果表明:水稻分蘖期,3种放蟹密度处理稻田底栖动物的种类数、密度、多样性指数和Pielou均匀度指数均无显著差异(P>0.05);在拔节期和扬花期,养蟹稻田底栖动物的种类数和密度均小于常规稻田,且与放蟹密度呈反比;常规稻田底栖动物的Shannon-Wiener多样性指数在拔节期和扬花期均显著高于高密度养蟹稻田(P<0.05),而只在拔节期显著高于低密度养蟹稻田(P<0.05),且Pielou均匀度指数也在拔节期显著高于低密度养蟹稻田(P<0.05);成熟期,3种处理底栖动物的种类数和密度均达到最低点,Shannon-Wiener多样性指数无显著差异(P>0.05),高密度养蟹稻田的Pielou均匀度指数显著高于常规稻田(P<0.05)。研究结果可为稻蟹共作稻田底栖动物的多样性保护和稻蟹共作技术的可持续发展提供理论指导,促进稻蟹共作技术的发展和推广。

Effect of rice-crab culture system on zoobenthos diversity in paddy field

Rice-crab culture system is a new ecological complex that combines rice culture with that of Eriocheir sinensis. Zoobenthos communities play a critical role in this complex ecological system. To our knowledge, however, there little research has been conducted on zoobenthos diversity in rice-crab culture systems. Much research has been directed towards the rational selection of rice variety, cultivation and management measures of rice-crab culture systems. To determine the effects of rice-crab culture systems on zoobenthos diversity in paddy fields, periodic sampling was conducted in rice-crab culture systems with different crab densities (10 ind·m^-2, LD; 30 ind·m^-2, HD) and in conventional paddy field (CK) at four key growth stages (tillering stage, elongation stage, flowering stage and maturity stage). The samples (a total of four per time) were analyzed for species composition, average density and diversity. At tillering stage, the results revealed no significant difference in species number, average density, diversity index and Pielou evenness index of zoobenthos faunal groups in the three treatments (^P > 0.05). At elongation and flowering stages, zoobenthos species number and average density were inversely related with crab density. Species number and average density of zoobenthos under LD and HD treatments was lower than those under conventional treatment. Shannon-Wiener diversity index of conventional treatment was significantly higher than that of HD treatment in both periods (^P< 0.05). However, the Shannon-Wiener diversity index and Pielou evenness index of conventional treatment were only significantly higher than those of LD treatment at elongation stage (^P < 0.05). At maturity stage, species number and average density of zoobenthos under three treatments were at the lowest levels. The Shannon-Wiener diversity index revealed no significant difference among the three treatments (^P> 0.05) and the Pielou evenness index of HD treatment was significantly higher than that of the conventional treatment (^P < 0.05). The study provided additional theoretical guidance about zoobenthos diversity protection and sustainable development of rice-crab culture systems. It provided another means of promoting the development of rice-crab culture technology.