REU: Episodic Winterkill, Pulsed Predation, and the Structure of Benthic Assemblages in Lentic Aquatic Ecosytems

偶尔的，偶发性的压力会对你产生长期的影响。 生态社区。 在浅水池塘或湖泊中， 冬季缺氧（低氧）可影响底栖无脊椎动物 社区，无论是通过直接死亡，或通过促进 鱼类捕食的脉冲 在这样的沃茨，海底区域成为 缺氧，而充足的氧气往往仍然接近冰水 接口. 为了生存，底栖生物分类群必须耐受低氧或 迁移到氧气充足的地区 然而，这样的行为 随着向冰水界面的活动或运动增加， 能够适应避免低氧条件的 在避免鱼类捕食方面适应不良。 虽然避免 低氧和鱼类出现时的行为变化 没有人研究过无脊椎动物 平衡这些相互矛盾的需求。 这项研究将探讨一种非生物 压力（冬季缺氧）和生物因素（鱼类捕食） 构建底栖无脊椎动物群落。 在实验室 实验中，底栖无脊椎动物平衡 避免缺氧和鱼类捕食的矛盾要求 将被审查。 分类群将根据其 底栖环境易受鱼类捕食 变得缺氧。 然后，这些预测将在 室外池塘，底栖区域缺氧， 被操纵了 底栖无脊椎动物的行为反应 在有鱼和没有鱼的池塘中发展缺氧将是 使用水下摄像机进行监控 以确定是否 物种脆弱性的实验室排名在 现场，鱼饲料将量化之前，期间，之后， 海底区域变得缺氧。 无脊椎动物分类群的缩写 在海底缺氧之前和之后， 冬季缺氧单独和与鱼类结合作用 捕食在构建底栖无脊椎动物组合。

Infrequent, episodic stress can have long-term effects on ecological communities. In shallow ponds or lakes, episodic winter hypoxia (low oxygen) can affect benthic invertebrate communities, either through direct mortality, or by promoting pulses of fish predation. In such waters, benthic areas become hypoxic while adequate oxygen often remains near the ice-water interface. To persist, benthic taxa must tolerate low oxygen or migrate to regions with adequate oxygen. However, behaviors such as increased activity or movement toward the ice-water interface that are adaptive in avoiding low oxygen conditions would be maladaptive in avoiding fish predation. Although avoidance of low oxygen and behavioral changes in the presence of fish have been documented separately, no one has examined how invertebrates balance these conflicting demands. This research will examine the interaction of an abiotic stress (winter hypoxia) and a biotic factor (fish predation) in structuring benthic invertebrate assemblages. In laboratory experiments, the ability of benthic invertebrates to balance the conflicting demands of avoiding both hypoxia and fish predation will be examined. Taxa will be ranked according to their vulnerability to fish predation as the benthic environment becomes hypoxic. These predictions will then be tested in outdoor ponds where hypoxia of the benthic region will be manipulated. The behavioral response of benthic invertebrates to developing hypoxia in ponds with and without fish will be monitored using an underwater video camera. To determine if laboratory rankings of species' vulnerability are observed in the field, fish diets will be be quantified before, during, and after the benthic zone becomes hypoxic. Abundance of invertebrate taxa before and after benthic hypoxia will allow us to determine the effect of winter hypoxia alone and in combination with fish predation in structuring benthic invertebrate assemblages.