Dissertation Research: Assessing the role of rapid evolution in trait-mediated predator effects on communities and ecosystems

捕食者通过减少猎物的丰度和诱导影响生态系统功能的物种特征的变化来改变生态系统。这些性状介导的捕食者对生态系统的影响既取决于猎物性状的进化，也取决于这些性状对捕食风险的反应。因此，捕食者和猎物的进化史是捕食者对群落和生态系统影响的基础。pi将把捕食者的线索引入到含有特立尼达孔雀鱼（Poecilia reticulata）的实验溪流中，这些孔雀鱼的种群已经与捕食者隔离了零到数千年。测量孔雀鱼的行为、代谢和营养过程将评估捕食者对孔雀鱼特征的影响，以及捕食者效应对捕食者和猎物进化史的依赖性。无脊椎动物和藻类群落、初级生产力和养分循环的相应测量将评估诱导的性状变化如何转化为溪流群落和生态系统过程中有生态意义的差异。人类活动导致的顶级捕食者减少是对生物多样性和生态系统服务的全球性威胁。了解捕食者构建自然系统的机制对于预测不确定未来的生物多样性和生态系统服务是必要的。最近的证据表明，当代的进化可以极大地影响生态过程的结果，而pi将评估猎物的快速进化如何介导捕食者对自然系统的影响。一名博士生将接受这项研究的培训，pi将把这项研究与高中生物学生的持续推广联系起来，使用实践研究项目来教授生物学原理。

Predators alter ecosystems both by reducing the abundance of prey and by inducing change in species traits that influence ecosystem function. These trait-mediated predator effects on ecosystems depend on the evolution of both prey traits and the responsiveness of those traits to predation risk. The evolutionary history of predator and prey thus underlies the influence of predators on communities and ecosystems. The PIs will introduce predator cues to experimental streams containing Trinidadian guppies (Poecilia reticulata) from populations that have been isolated from predators for zero to thousands of years. Measurements of guppy behavior, metabolism, and nutrient processing will assess the influence of predators on guppy traits and the dependence of predator effects on the evolutionary history of predator and prey. Corresponding measures of invertebrate and algal communities, primary productivity, and nutrient cycling will assess how induced trait change translates into ecologically meaningful differences in stream communities and ecosystem processes. Human-driven top-predator loss is a global threat to biodiversity and ecosystem services. Understanding the mechanisms by which predators structure natural systems is necessary to predict biodiversity and ecosystem services into an uncertain future. Recent evidence indicates that evolution in contemporary time can greatly affect the outcome of ecological processes, and the PIs will assess how rapid evolution by prey mediates the influence of predators on natural systems. One PhD student will be trained in conducting this research, and the PIs will link this research to ongoing outreach with high school biology students, using hands-on research projects to teach principles of biology.