Fish induced macrophyte loss in shallow lakes: top–down and bottom–up processes in mesocosm experiments
Fish induced macrophyte loss in shallow lakes: top–down and bottom–up processes in mesocosm experiments
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DOI：
10.1046/j.1365-2427.2002.00963.x
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发表时间：
2002-11
影响因子：
2.7
通讯作者：
Adrian E. Williams;B. Moss;J. Eaton
中科院分区：
文献类型：
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作者：
Adrian E. Williams;B. Moss;J. Eaton
总结1。在过去的20年里，英国具有特殊科学价值的地点的大型植物的消失已经变得很普遍。其中一个原因可能是钓鱼业趋势的变化，这是一个价值数百万英镑的产业，对水生生态系统有着巨大的影响。放养鲤类鱼类是一种常见的垂钓管理做法，但特定的鱼类种类及其生物量的分布可能对生态系统至关重要。2. 在英国柴郡的一个肥沃的浅湖Little Mere中，研究了不同大小的鲤鱼（Cyprinus carpio）、蟑螂（Rutilus Rutilus）、鲷鱼（Abramis brama）和鲱鱼（Tinca Tinca）在生物量0 - 800 kg hm2的试验性中生态系统中处理对水生生态系统的影响。具体而言，研究了不同处理对大型植物生长、底栖和大型无脊椎动物种群、水体化学、附生植物生产和浮游生物存活的影响。3. 鲤鱼对大型植物的危害大于鲷鱼、鲱鱼，尤其是蟑螂。鱼的生物量对大型植物的生长程度有不利影响。4. 大型植物生长的下降很可能是附生植物生长增加的结果，这可能减少了植物可获得的光和二氧化碳的量。没有观察到鱼类对大型植物的直接影响。5. 化学数据表明，无机氮水平很低，从鱼类排泄物中释放的氮，随后被立即吸收，可能是刺激附生植物生长和随后的大型植物损失的主要因素。即使在对照组中，磷的浓度也有所增加，而且可以获得大量的磷。因此，磷的刺激作用可以忽略不计。与大型植物相关的大型无脊椎动物与附生负荷呈正相关，但对附生生长程度没有影响。受到扰动的沉积物或浮游植物的遮挡也不重要。
SUMMARY 1. Macrophyte loss from Sites of Special Scientific Interest in England has become widespread over the last 20 years. One reason for this may be changing trends in angling, a multimillion pound industry that has an enormous impact on aquatic ecosystems. Stocking with cyprinid fish is a common angling management practice but the particular fish species and distribution of their biomass may be crucial to the ecosystem. 2. Carp (Cyprinus carpio), roach (Rutilus rutilus), bream (Abramis brama) and tench (Tinca tinca) at biomasses ranging from 0 to 800 kg ha )1 and at various sizes were placed into experimental mesocosms in Little Mere, a shallow, fertile lake in Cheshire, U.K. The effects these treatments had on the aquatic ecosystem were studied over two summers. Specifically the effects of the treatments on macrophyte growth, benthic and macrophytic macro-invertebrate populations, water chemistry, epiphyton production and plankton survival were investigated. 3. Carp had a greater detrimental effect on the macrophytes than bream, tench and in particular roach. A biomass of fish > 200 kg ha )1 adversely affected the extent of macrophyte growth. 4. The decline in macrophyte growth was most likely as a result of increased epiphyton growth that probably reduced the amount of light and carbon dioxide available to the plant. There were no observed direct fish impacts on macrophytes. 5. The chemical data suggested that inorganic nitrogen levels were low and it is possible that release of nitrogen, from fish excreta, followed by immediate uptake, could have been a major factor stimulating epiphyton growth and subsequently macrophyte loss. Phosphorus concentrations increased even in the controls and substantial amounts were available. Phosphorus stimulation can therefore be discounted. Macrophyte-associated macro-invertebrates were positively correlated with epiphyton load but had no impact on the extent of epiphytic growth. Shading from disturbed sediment or phytoplankton was also unimportant.