The Role of Top-Down and Bottom-Up Control for Phytoplankton in a Subtropical Shallow Eutrophic Lake: Evidence Based on Long-Term Monitoring and Modeling
The Role of Top-Down and Bottom-Up Control for Phytoplankton in a Subtropical Shallow Eutrophic Lake: Evidence Based on Long-Term Monitoring and Modeling
复制标题
自上而下和自下而上控制亚热带浅水富营养化湖泊浮游植物的作用：基于长期监测和建模的证据
DOI：
10.1007/s10021-020-00480-0
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发表时间：
2020-02-03
期刊：
影响因子：
3.7
通讯作者：
Jeppesen, Erik
中科院分区：
文献类型：
--
作者：
Mao, Zhigang;Gu, Xiaohong;Jeppesen, Erik
湖泊生态系统受到一系列人为压力的影响，特别是富营养化，在某些情况下，还受到放养和/或过度捕捞顶级捕食者鱼类的影响，所有这些因素都对食物网结构产生影响，并可能导致令人讨厌的蓝藻占主导地位。退化湖泊的恢复需要深入了解自上而下的自下而上的调节力量的相对作用。虽然这些力量在温带湖泊的知识是广泛的，相对较少的是知道他们在亚热带湖泊的草食性和底栖喂养鱼类的重要性更高的作用。在这里，我们分析了一个长期的监测数据集亚热带，浅水太湖，中国，并采用随机森林回归研究浮游植物是如何与环境变量和生物组合。研究结果表明，浮游植物的生物量和密度随底栖和动栖鱼类生物量的增加而增加，随氨氮浓度、氮磷比和浮游动物生物量的增加而减少，而对气候波动和食鱼动物生物量变化的响应较弱。较高的营养水平的影响解释了浮游植物生物量的变化，营养和气候因素。此外，浮游动物的比例显着降低，浮游植物生物量和枝藻个体生物量的下降强调了自上而下的控制在调节浮游植物广泛放养的重要性。我们的研究结果提供了深入了解鱼类管理如何与流域级恢复措施相结合，以保护和提高水质。
Lake ecosystems are exposed to a range of anthropogenic pressures, particularly eutrophication, and in some cases also stocking and/or overfishing of top-predator fish species, all factors that have implications for the food web structure and which could lead to dominance of nuisance cyanobacteria. Restoration of degraded lakes demands insight into the relative role of top-down for bottom-up regulating forces. While knowledge about these forces in temperate lakes is extensive, comparatively little is known of their role in subtropical lakes where the importance of herbivorous and benthic feeding fish is higher. Here, we analyzed a long-term monitoring data set on subtropical, shallow Lake Taihu, China, and applied random forests regression to examine how phytoplankton was related to environmental variables and biotic assemblages. Our results indicate that the biomass and density of phytoplankton increased with increasing biomass of benthivorous and zooplanktivorous fish and decreased with increases in ammonium concentrations, the nitrogen to phosphorus ratio, and zooplankton biomass, while the response to climate fluctuations and changes in the biomass of piscivores was weak. Effects of higher trophic levels explained as much of the variance in phytoplankton biomass as did nutrients and climatic factors. Moreover, the remarkably reduced ratio of zooplankton to phytoplankton biomass and the decline in cladoceran individual biomass emphasized the increasing importance of top-down control in regulating the phytoplankton following extensive stocking. Our findings offer insight into how fish management may be combined with catchment-level restoration measures to conserve and enhance water quality.