Submerged macrophytes facilitate dominance of omnivorous fish in a subtropical shallow lake: implications for lake restoration

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• 作者：Jinlei Yu ; Zhengwen Liu ; Hu He ; Wei Zhen ; Baohua Guan ; Feizhou Chen…
• 刊名：Hydrobiologia
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：775
• 期：1
• 页码：97-107
• 全文大小：871 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Hydrobiology
  Ecology
  
• 出版者：Springer Netherlands
• ISSN：1573-5117
• 卷排序：775

文摘

Biomanipulation based on removal of coarse fish, piscivorous fish stocking and sometimes also planting of submerged macrophytes has been used to restore temperate eutrophic shallow lakes. However, in warmer lakes, omnivorous fish are more abundant and apparently less well controlled by the piscivores. We investigated the food web structure and energy pathways of fish in the restored part of subtropical Lake Wuli, China, using gut contents analysis (GCA) and the IsoSource model based on stable isotope analysis (SIA) data. We found that omnivores dominated the fish community in terms of numbers. GCA showed that cyclopoid copepods constituted the main food item for the planktivores, while all adult omnivorous fish fed mainly on macrophytes. The IsoSource SIA model supported these results. Furthermore, piscivores consumed shrimps rather than juvenile omnivores, and the SIA analysis revealed no trophic links between piscivores and adult omnivores or zooplanktivores. We conclude that macrophytes constituted an important food item for omnivores, potentially promoting population growth of omnivores as control by piscivores was weak. This may yield a high predation pressure on both zooplankton and on macrophytes, possibly preventing the establishment of a stable macrophyte state following restoration of eutrophic lakes unless the fish density is regularly controlled.KeywordsSubmerged macrophytesFish dietsAlternative preyStable isotopeFood webLake restoration