Mayflies, Sowbugs, and Caddisflies, Oh My!

After being slightly afraid of a repeat of the cold and wet weather during our first outing to Gales Creek, we were very relieved to arrive at our dry, a slightly warmer site. We talked about the plantings we did last time- how native trees and shrubs will create habitat for our incredible birds already on site as well as other animals in the area, will create shade and more oxygen in Gales Creek, and will stabilize our banks from eroding and causing a bunch of sediment to stay in the water column of the creek.

We broke up into two groups and began coffee bagging and mulching plants. Coffee bags will help give our native trees and shrubs a head start above the Reed Canary Grass. The mulch will help retain moisture for the plants so they do not dry out and die in the summer months. Students worked incredibly fast and efficiently so fast we ran out of coffee bags before the second group could even help out!

The other station required a bit more contact with the stream. Students washed off rocks into kick nets to collect macroinvertebrates who live in the stream. These macroinvertebrates are a good indicator of water quality. Some species of macroinvertebrates are very sensitive to pollution in the water and therefore their presence indicates a fairly healthy stream. We sampled the river and found quite a few cool macros. We found a Stonefly, Aquatic Sowbugs, Aquatic Earthworms, Mayflies, Blackfly Larvae, Caddisflies, and Craneflies. The Caddisflies we found were Casemaker Caddisflies, which use organic materials such as leaves in the stream to build their own case! We saw a few of them trying to ditch their case and peek out to say hello.

The average of our Pollution Tolerance Index among all 6 groups that sampled the creek was 3 which according to the PTI formula indicates Poor Stream Quality. Because we did find quite a few Mayflies and Caddisflies, which are really sensitive to pollution, our stream quality results from the test may not completely, accurately reflect the health of the stream. Some factors that may be a cause for error are that it is winter and many bugs are not reproducing and hatching new bugs. Also, our PTI does not account for the number of macros of a specific Order we find, just that its Order is represented. While we did not find a wide variety of pollution sensitive macroinvertebrates, we did find quite a few of the ones that were represented. It will be interesting to see how the biodiversity of the bugs changes over time- even as soon as the summer!

Lastly, we created leaf packs to collect macroinvertebrates in to examine in May. We planted a few Ponderosa Pines and Pacific Willow and headed back to the bus.

Thank you, Forest Grove High School, for working with such dedication, researching macroinvertebrates with great curiosity, and just being wonderful! We will see you soon!

Thank you, Dave for stopping by to check out our hard work!

Thank you, Clean Water Services, for funding this project!

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