Predator-prey interactions: effects of carp predation on Tubificid dynamics and carp production in experimental fishpond

Effects of predation by carp (Cyprinus carpio L) were analysed in an experimental fishpond where the main components of the benthic fauna were tubificids. Enclosures inaccessible to fishes were compared with the rest of the pond stocked with 30 young carps (1⁺). Fish predation reduced the density, biomass and production of prey; the production of Tubificidae inside the enclosures was 1.7 times higher than that of the part of the pond stocked with fishes. On the other hand tubificid turnover ratios (P/B) inside and outside enclosures were not significantly different (respectively 5.57 and 5.38), and the size distribution of tubificids was not significantly modified. The ratio of the energetic equivalent of net fish production to biomass of tubificids consumed was 5.59%.     

芽胞杆菌对鱼池微生物群落代谢功能的影响

利用Biotog平板,以施用与不施用芽胞杆菌的鱼塘为研究对象,研究鱼塘水体与表泥不同空间的微生物群落代谢功能的差异。结果表明：芽胞杆菌提高了水体微生物群落代谢的平均活性,及对氨基酸类、胺类、羧酸类、聚合物及其它类碳源的利用能力,提高了水体微生物群落代谢的多样性（Shannon均度、Simpson指数、McIntosh均度差异显著）;两池表泥微生物群落代谢平均活性差异较小,对同一碳源的利用差异不大,芽胞杆菌显著提高了表泥的Simpson指数,但表泥的McIntosh指数显著低于对照池。总体而言,鱼塘施用芽胞杆菌,水体微生物群落代谢功能所受的影响大过表泥,芽胞杆菌通过提高水体微生物群落代谢活性,提高了水体微生物对有机污染物的降解能力,以此改善池塘的生态环境。     

张掖人工池塘浮游植物群落研究

对张掖具代表性的五个人工地塘的浮游植物四季采样,共获７９种（未鉴定到种的按一种计）,其中蓝藻１２种,绿藻３２种,硅藻１８种,甲藻３种,裸藻８种,黄藻、隐藻和金藻各２种。浮游植物的年平均密度为５７８．２３６万个／Ｌ,生物量为３．１０４０ｍｇ／Ｌ。不同池塘中的现存量有一定的差别,种类以流泉最高,生物量以市鱼场最高。文中对浮游植物的季节变动作了分析,并对浮游植物的产鱼潜力进行了初步估算。     

The fauna in the vegetation of a moorland fishpond as revealed by different methods of collecting

The fauna was sampled regularly by sweeping with a net, by means of a quantitative sampler and in mats of artificial Littorella. The three methods were found to be complementary. Only the second yielded reliable quantitative data, but it was the most time-consuming. The artificial-vegetation method was the quickest, and comparable samples could be taken regularly without harm to the environment. A few species were not attracted to the artificial vegetation. The net revealed that some species were more abundant in certain species of plant than in others. The artificial vegetation was particularly suitable for sampling in deep water. Moreover it captured the smallest specimens, which could pass through the sweep-net because the mats could be brought up inside a net of finer mesh.     

崇明东滩抛荒鱼塘的自然演替过程对水鸟群落的影响

人工湿地抛荒的现象普遍存在,但针对抛荒后的自然演替过程对水鸟群落影响的研究较少.于2007、2008、2011年对崇明东滩自然抛荒的人工鱼塘水鸟群落展开调查,探究抛荒后的自然演替过程对水鸟群落结构及不同水鸟类群的影响.3a累计观察到水鸟59种12819只,隶属6目12科.其中抛荒前最多,共53种11001只;抛荒第1年22种1673只;抛荒第4年最少,9种145只.鱼塘抛荒后水鸟种类和数量下降剧烈,物种多样性先上升再下降,均匀度逐年上升,优势度先下降再上升.方差分析结果表明,5个群落特征都存在极显著年度差异(P1＜0.01;P2＜0.01;P3＜0.01;P4=0.003;P5＜0.01).非参数检验结果表明,不同类群水鸟的种类和数量逐年下降趋势明显,且年际差异极显著.即抛荒后的自然演替过程对水鸟群落产生了不利影响.建议采取人工管理措施防止旱化,增加环境异质性,恢复水鸟群落多样性.