Repeated Fish Removal to Restore Lakes: Case Study of Lake Væng, Denmark—Two Biomanipulations during 30 Years of Monitoring
Repeated Fish Removal to Restore Lakes: Case Study of Lake Væng, Denmark—Two Biomanipulations during 30 Years of Monitoring
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DOI：
10.3390/w9010043
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发表时间：
2017-01
期刊：
影响因子：
3.4
通讯作者：
M. Søndergaard;T. Lauridsen;L. Johansson;E. Jeppesen
中科院分区：
文献类型：
--
作者：
M. Søndergaard;T. Lauridsen;L. Johansson;E. Jeppesen
生物操纵除鱼已被用于许多浅水湖泊作为一种方法，以改善湖泊水质。在这里，我们提出并分析了30年的化学和生物数据，从浅和16公顷的大湖Vaeng，丹麦，这已被biomanipulated两次与20年的时间间隔，通过删除蟑螂（Rutilus rutilus）和鲷（Abramis brama）。经过这两次生物操纵，Vaeng湖从一个浑浊的，植物浮游植物为主的状态转变为一个清晰的，水生植物为主的状态。叶绿素a由60-80 μg·L-1下降到10-30 μg·L-1，以伊乐藻为主的沉水植物覆盖度由<0.1%上升到70%~ 80%。夏季平均总磷从0.12 mg·L-1降至0.07 mg·L-1，总氮从1.0 mg·L-1降至0.4 mg·L-1。在季节尺度上，磷和叶绿素浓度从夏季最大值在混浊的条件下，冬季最大值在明确的条件下。Vaeng湖的未来是不确定的，通过地下水的磷负荷相对较高，沉积物中移动的磷池的积累使湖泊最终可能会恢复到浑浊的状态。重复的鱼类清除可能是一个相关的管理策略，适用于浅水湖泊相对较高的外部营养负荷。
Biomanipulation by fish removal has been used in many shallow lakes as a method to improve lake water quality. Here, we present and analyse 30 years of chemical and biological data from the shallow and 16 ha large Lake Vaeng, Denmark, which has been biomanipulated twice with a 20-year interval by removing roach (Rutilus rutilus) and bream (Abramis brama). After both biomanipulations, Lake Vaeng shifted from a turbid, phytoplankton-dominated state to a clear, water macrophyte-dominated state. Chlorophyll a was reduced from 60–80 μg·L−1 to 10–30 μg·L−1 and the coverage of submerged macrophytes, dominated by Elodea canadensis, increased from <0.1% to 70%–80%. Mean summer total phosphorus was reduced from about 0.12 to 0.07 mg·L−1 and total nitrogen decreased from 1.0 to 0.4 mg·L−1. On a seasonal scale, phosphorus and chlorophyll concentrations changed from a summer maximum during turbid conditions to a winter maximum under clear conditions. The future of Lake Vaeng is uncertain and a relatively high phosphorus loading via the groundwater, and the accumulation of a mobile P pool in the sediment make it likely that the lake eventually will return to turbid conditions. Repeated fish removals might be a relevant management strategy to apply in shallow lakes with a relatively high external nutrient loading.