Why do Stream Waders sample aquatic invertebrates?
Aquatic invertebrates, such as mayflies, caddisflies, stoneflies and dragonflies, are good indicators of stream health. Invertebrates vary in their sensitivity to pollutants so a healthy stream will have pollution sensitive ones as well as tolerant ones, but an unhealthy stream will have only the tolerant organisms. Since some of them live for over a year, and don’t move around much, they can tell us a good bit about the quality of the stream over time. Also, these animals are fairly easy to sample using fairly inexpensive equipment and are pretty easy to identify in a laboratory.
