基于围隔实验研究鳙在亚热带贫-中营养水库的下行效应  

Research about top-down effects of bighead carp(Aristichthys nobilis)in a subtropical,oligo-mesotrophic reservoir based on an enclosure experiment

作　　者：赵帅营 孙育平 韩博平[4] ZHAO Shuaiying;SUN Yuping;HAN Boping(Yunnan Key Laboratory of Plateau Geographical Processes and Environment Change,Yunnan Normal University,Kunming 650500,China;Faculty of Geography,Yunnan Normal University,Kunming 650500,China;Institute of Animal Science,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,China;Institute of Hydrobiology,Jinan University,Guangzhou 510632,China)

机构地区：[1]云南省高原地理过程与环境变化重点实验室,昆明650500 [2]云南师范大学地理学部,昆明650500 [3]广东省农业科学院动物科学研究所,广州510640 [4]暨南大学水生生物研究所,广州510632

出　　处：《生态科学》2023年第6期1-10,共10页Ecological Science

基　　金：国家自然科学基金项目(31460131,31960250);国家留学基金委“西部地区人才培养特别项目”(201508535008);云南省John P.Smol院士工作站(202005AF150005)。

摘　　要：为了解鳙在低营养水体中的下行效应,于秋冬季节在流溪河水库开展了原位围隔实验。该实验在水库原水中进行,并根据鳙的生物量(0 g·m^(–3)和3 g·m^(–3))设置了对照组和有鱼组。研究结果显示:总氮(TN)、总磷(TP)、氮磷质量比(TN:TP)和叶绿素(Chl a)在加入鳙后均未发生显著变化。所有围隔中浮游动物群落均是以小个体种类为主,缺少大型枝角类。鳙的存在促进了轮虫和剑水蚤丰度的增加,但降低了枝角类和哲水蚤的丰度,并导致枝角类、桡足类及浮游动物的生物量显著下降。有鱼围隔中甲壳类的平均体长(352—396μm)显著低于对照组(547—592μm)。添加鳙使浮游植物优势门类绿藻与大型浮游植物(最大轴直径≥30μm)的生物量显著升高,但对优势门类硅藻、金藻和甲藻、小型浮游植物(最大轴直径<30μm)以及浮游植物的生物量无显著影响。这些结果显示,鳙对浮游动物群落产生了强烈的下行效应,对浮游植物群落则未产生明显的级联效应。我们的结果表明,在缺少大型牧食性枝角类的低营养水体中,鳙在低温季节对水质的影响可能相对有限。To examine the top-down effects of bighead carp(Aristichthys nobilis)in freshwaters with a low trophic state,an in situ enclosure experiment was carried out during the autumn-winter period in a subtropical,oligo-mesotrophic reservoir located in Guangdong Province,China by manipulating the biomass(0 g·m^(–3)vs.3 g·m^(–3))of bighead carp.Bighead carp stocking had no significant effect on total nitrogen(TN),total phosphorus(TP),TN:TP mass ratio,and chlorophyll a.In all enclosures,the zooplankton community was dominated by small-sized species,with Daphnia being scarce.The abundance of rotifers and cyclopoids was markedly increased with fish addition,whereas the abundance of cladocerans and calanoids was negatively affected by fish,thereby significantly lowering total zooplankton biomass and the biomass of cladocerans and copepods.Also,selective predation by bighead carp significantly reduced mean crustacean length from 547-592μm to 352-396μm.The biomass of Chlorophyta and large phytoplankton(greatest axial linear dimension,GALD≥30μm)showed positive response to fish addition.In contrast,there was no significant effect of fish on the biomass of Bacillariophyta,Chrysophyta,Pyrrophyta and small phytoplankton(GALD<30μm),as well as total phytoplankton biomass.These results indicate that bighead carp had a strong top-down effect on the zooplankton community,but exerted no cascading effect on the phytoplankton community.Our findings suggest that during the low-temperature season,bighead carp may have margin effects on the water quality in low trophic-state waterbodies lacking large-bodied herbivorous cladocerans.

关 键 词：滤食性鱼类 低营养水平 级联效应 浮游动物 浮游植物 大型枝角类 营养循环 

分 类 号：Q178.1[生物学—水生生物学]