Horizontal distribution of cladocerans in arctic Greenland lakes – impact of macrophytes and fish
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- 作者：Lauridsen ; Torben ; Jeppesen ; Erik ; Landkildehus ; Frank ; Sø ; ndergaard ; Martin
- 关键词：Daphnia pulex ; zooplankton ; arctic lakes ; Arctic charr (Salvelinus alpinus) ; shore avoidance ; macrophytes
- 刊名：Hydrobiologia
- 出版时间：2001
- 出版年：2001
- 期刊代码：7_00188158
- 类别：et
- 卷：442
- 期：1/3
- 页码：107-116
- 数据来源：sp
摘要
Submerged macrophytes may play an important role as a refuge for zooplankton against predators. However, a recent study suggests that their importance depends on the trophic state of the lake. We studied the impact of fish and macrophytes on the horizontal distribution of pelagic cladocerans in 56 oligotrophic arctic Greenland lakes. In north-east and western Greenland, zooplankton was sampled in the near-shore (littoral) and central (pelagial) part of all lakes and fish were sampled with multiple mesh-sized gill nets. Macrophytes were visually estimated in the littoral. In north-east Greenland, 5 taxa of cladocerans were found, while 14 taxa were recorded in western Greenland. Daphnia pulex occurred only in fishless lakes in both northeast and western Greenland and avoided the near-shore areas in the shallow and deep lakes. Bosmina spp. and Holopedium gibberum were evenly distributed between the littoral and the pelagial in the deep and shallow fishless lakes. However, their near-shore density was lowest in the presence of fish. Macrophyte-related and benthic cladocerans concentrated either in the littoral or were evenly distributed between the littoral and the pelagial, irrespective of depth and fish presence or absence. Macrophytes had no impact on the horizontal distribution of pelagic cladocerans. Thus, it is concluded that horizontal heterogeneity of Bosmina spp. and Holopedium gibberum might be affected by the presence of fish.