The Effects of Stream Flow and Predation on Trophic Interactions Among Juvenile Cyprinid and Centrarchid Fishes Below Beaver Ponds

河流流量的年度变化与无脊椎动物丰度和鲤科和中心类幼鱼密度的剧烈波动有关。在没有中心型捕食的情况下，小型鱼类会抑制池塘栖息地的无脊椎动物数量，但不会抑制猎物数量，而中心型捕食者会将幼鱼限制在浅水的猎物避难所，同时进行种类和大小的选择性捕食。这项研究是这些发现的合乎逻辑的延伸。实验将量化溪流、中心捕食和幼鱼密度对河狸池塘下的无脊椎动物资源和鲤科和中心类幼鱼的同时影响。将检验与以下四个问题有关的假设：1.鲤科和中心类幼鱼的生长和存活对鱼类的变化有多敏感密度和什么，如果有的话，无脊椎动物资源的种间利用对这些鱼类的生长和存活有影响吗？2.河狸池塘下面水流状况的变化是否改变了鲤科和中心类幼鱼利用资源的强度和结果？3.中心类捕食者对鲤科幼体和中心类的资源利用强度和结果有什么影响？4.河狸池塘下方流态的变化如何影响捕食者-猎物的相互作用和鲤科和中心类幼鱼对无脊椎动物资源利用的结果？这项研究将极大地加深我们对溪流鱼类生长和生存规律的理解。它还将提高我们将水文状况对营养相互作用的影响纳入北温带水生景观新兴概念模型的能力。

Annual variation in stream flow is associated with dramatic fluctuations in invertebrate abundance and the density of juvenile cyprinid and centrarchid fishes. In the absence of centrarchid predation, small fishes depress invertebrate abundance in pool habitats but not riffles, and centrarchid predators restrict juvenile fishes to shallow riffle refugia while engaging in species- and size-selective predation. This research is a logical extension of these findings. Experiments will quantify the simultaneous influence of stream flow, centrarchid predation, and juvenile fish density on invertebrate resources and juvenile cyprinid and centrarchid fishes below a beaver pond. Hypotheses will be tested related to the following four questions: 1. How sensitive is the growth and survivorship of juvenile cyprinid and centrarchid fishes to changes in fish density and what, if any, effect does interspecific use of invertebrate resources have on the growth and survivorship of these fishes? 2. Do changes in flow regime below beaver ponds shift the intensity and outcome of resource use by juvenile cyprinid and centrarchid fishes? 3. What effect do centrarchid predators have on the intensity and outcome of resource use by juvenile cyprinids and centrarchids? 4. How do changes in flow regime below beaver ponds effect predator-prey interactions and the outcome of invertebrate resource use by juvenile cyprinid and centrarchid fishes? This research will greatly enhance our understanding of the regulation of growth and survival in stream fishes. It will also increase our ability to incorporate the effect of hydrologic regime on trophic interactions into emerging conceptual models of north-temperate aquatic landscapes.