Date of Award


Document Type

Union College Only

Degree Name

Bachelor of Science






pools, macroinvertebrates, structure, community, migration


Benthic macroinvertebrates, juvenile insects that reside on the rocky substrates in rivers and streams, are commonly used as indicators of river health. Macroinvertebrates are typically sampled on the riffles of a stream, regions of shallow, often-exposed rock with well-oxygenated water. Since they are more vulnerable to predation when away from the protection of the rocky crevices of a riffle, the least risky behavior for these organisms is to remain at the oviposition site. Pools are not typically used as oviposition sites by macroinvertebrates. Thus, if these organisms are found in pools, it implies downstream migration. I studied migration patterns in macroinvertebrates by placing artificial habitat in deep water sections of a healthy river in southeastern Connecticut. While the study produced a large data set appropriate for answering questions about temporal trends, macroinvertebrate density, and about biologic river health, I narrowed my investigation to studying the community structure in pools. Thus, my questions are: Will aquatic macroinvertebrates establish communities via migration in deep water pools given the appropriate substrate? And if so, is the community structure in the pools different than the structure in the riffles? The results indicated that pools are subsets of riffle community structure and may function as important refuge sites.