The researchers compared fish communities in different streams of the Pine River in Michigan. They found that fish species richness increased with stream size, with more species in larger streams. Adventitious streams had more fish species than headwater streams, and their fish communities were more similar to the mainstem river. However, the fish species in adventitious streams varied more month-to-month. Despite similarities in habitat, adventitious streams were warmer than headwater streams. This shows that factors like stream connectivity and temperature, not just stream size, affect the types of fish found in streams.