The instability of reservoir habitats and its impact on food webs

**** 这项研究的目的是评估水库不稳定的物理环境限制其食物网生产力的潜力。水库，虽然表面上类似于湖泊，是工程系统的运作，以最大限度地提高水电输出或水储存。 它们往往位于陡峭的盆地中，具有高水力吞吐量，并且比天然湖泊经历更大的水位变化。在天然湖泊的生产力是由三个主要的能量流动途径，远洋，沿岸的和深水驱动;然而，在水库的远洋一般是占主导地位的，和沿岸的和深水底栖动物的途径一般是次要的，由于相结合的下拉和深，陡峭的盆地。此外，水周转可以足够快，以限制浮游动物的发展，这通常是缺席的河流输入水库，并缺乏游泳能力，以抵抗平流夹带在水库流出。 ** 该提案提出了将食物网与水力应力相结合的模型，并预测浮游动物和鱼类生物量在高通量系统中将较低。还提出了一个物理指标的沿岸的稳定性，结合下降和因素，减少透光层深度。这一指数应与沿岸的能流的稳定同位素测量相关联。拟议的研究还将审查生境稳定性对鱼类和无脊椎动物体内汞生物累积的影响。** 在加拿大，水利开发是否符合《加拿大渔业法》对环境评估至关重要，因此水库的渔业生产力是一个重要的环境问题。为模拟对营养动力学的影响而提出的生境指数可能对模拟其他类型的生态系统压力具有有用的类似物。

**** The goal of this research is to assess the potential of the unstable physical environment of reservoirs to limit the productivity of their food webs. Reservoirs, although superficially similar to lakes, are engineered systems operated to maximize hydroelectric output or water storage. They tend to be situated in steep-sided basins, have high hydraulic throughput, and experience greater changes in water level than natural lakes. Productivity in natural lakes is driven by three major energy flow pathways, the pelagic, the littoral and the profundal; however in reservoirs the pelagic is generally dominant, and the littoral and the profundal zoobenthic pathways are generally of minor importance due to a combination of draw-down and the deep, steep-sided basins. In addition, water turnover can be sufficiently rapid to limit the development of zooplankton, which are usually absent from the riverine inputs to reservoirs, and lack the swimming ability to resist advective entrainment in the reservoir outflow. ** The proposal presents models that couple food webs to hydraulic stress, and predict that zooplankton and fish biomass will be lower in high throughput systems. A physical index of littoral stability that combines drawdown and factors that reduce photic zone depth is also presented. This index should be correlated to stable isotope measures of littoral energy flow. The proposed research will also examine the effect of habitat stability on mercury bioaccumulation in fish and invertebrates. ** In Canada, compliance of hydro-developments to the Canada Fisheries Act is critical to environmental assessment, and fisheries productivity of reservoirs is therefore an important environmental issue. The habitat indices proposed for modeling impacts on trophodynamics, may have useful analogues for modeling other types of ecosystem stresses.****