Macroinvertebrates of the Kinnickinnic

Temperature & Macroinvertebrates

Macroinvertebrates serve as a major food source for trout, and are an integral part of the normal energy and organic material processing system in streams. Because of temperature regime alteration, temperature-sensitive or thermally-cued macroinvertebrates are often reduced or eliminated, leaving only types with broad tolerance ranges. We conducted annual macroinvertebrate collections until 2013, now we conduct biannual collections.

Learn about our laboratory methods.

Temperature Tolerance

Many aquatic insects (especially mayflies) require a fluctuating diurnal temperature regime. Temperatures greater than 17 degrees Celsius (63 Fahrenheit) exceed the optimum for many stoneflies, mayflies, and caddis.

Clarke's Bugs

Clarke Garry is a retired professor of biology at the University of Wisconsin - River Falls. He created numerous articles on entomology and ecology and include information on the Abundant Scud, the Naked Caddis, the Winter Stonefly, the Rusty Crayfish, the Little Yellow, Common Burrowers, and the Humpless Casemaker.

A World of Life

"There's a whole world of life in rivers and streams. Living alongside fish, amphibians, reptiles, and wildlife are macroinvertebrates creatures that are large (macro) enough to be seen with the naked eye, and that lack a backbone (invertebrate). Aquatic insects, clams, snails, crayfish, worms and leeches are all macroinvertebrates. Some, like snails, live their whole lives in the water; others, like dragonflies, leave the water as adults to feed and reproduce. In streams, most macroinvertebrates live under or attached to submerged rocks, logs, and plants. Like all living things, they need oxygen to breathe, water of the right temperature to thrive and reproduce in, suitable habitat, and the right kind of food. When these requirements aren't met, these creatures will sicken and die.

Scientists and trained volunteers study macroinvertebrates to learn more about stream quality. The basic principle behind the study of macroinvertebrates is that some are more sensitive to pollution than others, so if you find lots of macroinvertebrates that can't tolerate pollution, you've found a pretty clean stream. On the other hand, if you find only macroinvertebrates that can live in polluted conditions, your stream may have a problem."

Source: United States Environmental Protection Agency - used with permission