The videos below provide more information about the ecosystem monitoring that we have done in the focal streams. We began to characterize the ecosystems of our experimental streams in what would become our guppy introduction site and the upstream control site a year before the guppy introduction.  We then introduced the guppies to the experimental stretch that was bounded by barrier waterfalls. 

​David Reznick provides an overview of stream ecosystems and how they differ from those on land.

Next, Keeley McNeil describes how we sample bugs and other invertebrates that live in the stream.

Kelley also demonstrates how we sample the sediment and organic material present in the stream, an important part of the ecosystem.

David returns to explain how we measure the algae and bacteria present in the stream.

Finally, Steve Thomas explains how we've tracked the flow of nitrogen through the ecosystem by dripping a stable isotope into the water.  Primary producers like algae incorporate it into proteins, then the proteins move through the ecosystem as insects eat algae, fish eat insects, fish and insects die and decay, and so on.  We have used this method into an experimental tool to characterize how guppies alter their ecosystem.