A key component of the overall health of the Metolius River and its tributaries is the status of the macroinvertebrates that populate the river. To better understand the river and its “bugs,” this summer Friends launched a project with renown bug expert (aquatic entomologist) Rick Hafele to collect samples of aquatic insects in the Metolius River system. The samples were sent to an aquatic insect taxonomist with Oregon State University in Corvallis who identified the species and the abundance of each from each sample location. Six sites in the Metolius River were sampled, 4 riffle habitat sites and 2 alternative habitat sites, and two sites in 2 tributaries, Canyon Creek and Lake Creek. The data on the species and abundance of bugs in each sample provides useful inform us about the habitat quality and variability.
Aquatic insects can tell us a lot about a river. Because they live and grow in the river during early life stages, the insects are exposed to all the water quality and habitat features that occur at a site. Measuring each of these parameters individually is useful, but the bugs integrate them and are thus good indicators of the type and quality of the habitat. These water quality and habitat features include water temperature, dissolved oxygen, pH, flow depth and velocity, and substrate composition, as well as toxic substances, algal growth and other factors.
Mayflies, stoneflies and caddisflies typically indicate clean, cold water with good flow and gravel and cobble substrate; the same type of habitat preferred by salmon, steelhead and trout.
The Final Report may be found on the Water Quality page, along with an Excel spreadsheet that includes granular data from the study.
Friends was able to do this work thanks to donations from our supporters. There has not been a study of this type in the Metolius River since the early 1990s and this study will give us an added metric for measuring river health. The data will also provide a baseline for comparison in the future, to detect any changes.
