Dissertation Research: Exploring Mechanisms of a Species Replacement in a Benthic Stream Community

非生物或生物过程是否主要负责自然群落的模式仍然是一个重要的问题。在河流中，生态学家传统上强调非生物因素，但越来越多的证据表明生物相互作用构成了生态群落。在俄亥俄州中部的溪流中，小龙虾物种的替代不可否认地正在发生，这为严格测试控制底栖无脊椎动物分布和数量的生物过程提供了一个独特的机会。三个潜在的机制将被探讨：不同的繁殖成功率，不同的竞争能力，特别是对鱼类捕食的不同脆弱性。具体来说，将确定捕食和竞争的直接和间接影响是否可以解释这种物种替代。实地调查、实验室实验和实地操作将阐明不同的大小、生长和生境利用如何影响这三种可选机制。由于这种小龙虾替代的持续性质，人们认为这是研究溪流中生物过程的模型系统。

Whether abiotic or biotic processes are primarily responsible for the patterns within natural communities remains an important question. In streams, ecologists have traditionally emphasized abiotic factors, but increasing evidence suggests that biotic interactions structure lotic communities. In central Ohio streams, a crayfish species replacement is undeniably occurring, providing a unique opportunity to test rigorously those biotic processes controlling benthic invertebrate distribution and abundance. Three potential mechanisms are to be explored: differential reproductive success, differential competitive ability, and particularly differential vulnerability to fish predation. Specifically, it will be determined if the direct and indirect effects of predation and competition can explain this species replacement. Field surveys, lab experiments, and field manipulations will clarify how differential size, growth, and habitat use influence each of these three alternative mechanisms. Because of the ongoing nature of this crayfish replacement, it is believed that this is to be a model system for studying biotic processes in streams.