Energy‐based top‐down and bottom‐up relationships between fish community energy demand or production and phytoplankton across lakes at a continental scale
Energy‐based top‐down and bottom‐up relationships between fish community energy demand or production and phytoplankton across lakes at a continental scale
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DOI：
10.1002/lno.11434
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发表时间：
2020-02
影响因子：
4.5
通讯作者：
M. Bartrons;T. Mehner;C. Argillier;M. Beklioğlu;P. Blabolil;T. Hesthagen;K. Holmgren;E. Jeppesen;T. Krause;S. Podgornik;P. Volta;I. Winfield;S. Brucet
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文献类型：
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作者：
M. Bartrons;T. Mehner;C. Argillier;M. Beklioğlu;P. Blabolil;T. Hesthagen;K. Holmgren;E. Jeppesen;T. Krause;S. Podgornik;P. Volta;I. Winfield;S. Brucet
尽管鱼类生物量水平相似，但由于大小结构和当地温度的差异，湖泊之间的鱼类群落摄食和生产率可能有所不同。因此，跨湖比较自上而下和自下而上的鱼类-浮游植物关系的强度和方向应考虑这些因素。我们利用生态学的代谢理论计算了 227 个欧洲湖泊中杂食性鱼类的大小和温度校正的群落能源需求 (CEDom) 和群落生产 (CP)，这些湖泊来自极地淡水、温带漫滩河流和湿地以及温带沿海河流的主要栖息地类型 (MHT)。我们将 CEDom 与总磷 (TP) 校正的叶绿素 a (Chl a) 浓度联系起来，以评估从鱼类到浮游植物的潜在自上而下的定向营养级联。此外，我们将叶绿素 a 与 CP 联系起来，以证明浮游植物对鱼类潜在的自下而上的影响。对于这两项分析，我们添加了鱼食性鱼类的 CED (CEDpi) 作为预测因子，以解释对杂食性鱼类群落的潜在捕食影响。 CEDom 与 TP 校正的 Chl a 呈弱正相关，但 MHT 之间的相关强度不同。相比之下，在整个数据集中，CP 始终与 Chl a 呈正相关。 CEDpi 对自上而下或自下而上的关系没有贡献。应用表征鱼类群落摄食和生产率的代谢变量使这些结果更加可靠，因为该方法考虑了跨湖比较中通常被忽视的鱼类大小和温度的影响。我们的结果表明，浮游植物对湖泊鱼类二次生产的自下而上的影响远强于鱼类对浮游植物生物量的自上而下的影响。
Fish community feeding and production rates may differ between lakes despite similar fish biomass levels because of differences in size structure and local temperature. Therefore, across‐lake comparisons of the strength and direction of top‐down and bottom‐up fish–phytoplankton relationships should consider these factors. We used the metabolic theory of ecology to calculate size‐ and temperature‐corrected community energy demand (CEDom) and community production (CP) of omnivorous fishes in 227 European lakes from major habitat types (MHTs) of polar freshwaters, temperate floodplain rivers and wetlands, and temperate coastal rivers. We related CEDom with total phosphorus (TP)‐corrected chlorophyll a (Chl a) concentrations to evaluate a potential top‐down directed trophic cascade from fish to phytoplankton. Furthermore, we related Chl a with CP to demonstrate potential bottom‐up effects of phytoplankton on fish. For both analyses, we added the CED of piscivorous fishes (CEDpi) as a predictor to account for potential predation effects on the omnivorous fish community. CEDom was weakly positively related with TP‐corrected Chl a, but the strength of the relationship differed between MHTs. In contrast, CP was consistently positively related with Chl a in the entire dataset. CEDpi did not contribute to top‐down or bottom‐up relationships. The application of metabolic variables characterizing fish community feeding and production rates makes these results robust because the approach accounted for the usually neglected effects of fish size and temperature in across‐lake comparisons. Our results suggest that bottom‐up effects from phytoplankton on fish secondary production in lakes are substantially stronger than top‐down effects from fish on phytoplankton biomass.