Bugs in our Waters

Aug 19, 2019
Small bugs in Central Oregon rivers and creeks can make a big impact on how we conserve and protect our lands.

by Rebekah Ratcliff

Long before the fish return to a creek, healthy waters are full of other kinds of swimming things.

Our streams and rivers are full of life. From the green algae to the smallest creatures to the largest salmon you have ever seen--the living things in our waters can tell us a lot about our streams. 

While the return of Chinook and other fish to our creeks is encouraging, there have been many other signs that our creeks are getting healthier. You might have never noticed them, or maybe you missed them! There are small animals in our waters, and if we watch them closely we can learn about the health of our streams.

Macroinvertebrates are small but still visible animals that lack a backbone. Insects like mayflies, mosquitoes, and beetles are all examples of macroinvertebrates or macros. Some of these animals are aquatic, which means they spend the majority of their lives in some form of water. In order to survive, these macros need our creeks, streams, and surrounding lands to be healthy.

Once you know what to look for, you can spot hundreds of different kinds of macroinvertebrates all throughout Central Oregon!

Some of these creatures like streams, some like rocks, and many of them look very, very different from one another. Each of these animals has adapted to survive in a specific home or habitat. By changing its body or its behavior, these animals are able to live in places where others might not. Some have suction cups to keep them from getting washed away, others have anchors or claws, and still others build protective shells.

No matter how these aquatic macroinvertebrates have adapted, they all need one thing: water. Aquatic macros begin their life in the water and then go through metamorphosis, like butterflies. During this transformation they change from an egg to larva and then to an adult stage. In order to complete their life cycle they must find waters they prefer.

Dragonfly rests above Lake Creek at the Metolius Preserve. Photo: Sue Anderson.
Dragonfly rests above Lake Creek at the Metolius Preserve. Photo: Sue Anderson.
Some macros do well in cold, clean water while others don’t mind poorer water conditions. By looking at which kinds of macros are present we can learn a lot about our stream quality and how it might be changing. Mayflies and stoneflies are really sensitive to pollution. Dragonflies and crayfish can survive a wide range of water quality. Then, leeches and water striders can survive in polluted waters. If there is an abundance of mayflies and a few dragonflies, we would think the stream has not been too polluted (remember, mayflies cannot live in polluted waters).

Kokanee salmon spawning in Spring Creek. Photo: Jay Mather.
Kokanee salmon spawning in Spring Creek. Photo: Jay Mather.
Macros aren’t only picky about pollution though; they each prefer a certain water temperature, clarity, and look for many other factors to find their perfect home in our streams. Understanding the communities of macroinvertebrates that are living in our waters can tell us more about who else might be able to live there. There are macros that are good indicators! Their presence in our streams gives us ideas of how healthy the waters are. So by finding mayflies, we know that our stream is not polluted, is nice and cool, and might be a good home for fish in the future. 


Like other
systems in our environment, many different factors surrounding a stream are interconnected. These factors work together. When the lands are healthy and grow, the stream is shaded. When the stream is shaded it stays cool. When a stream stays cool it can be the home for all kinds of organisms. These organisms, like macroinvertebrates, keep the stream healthy by eating algae and cleaning up the waters to keep the system going strong.


Small child looks at a bug caught in a display jar. Photo: Chip Belden.
Small child looks at a bug caught in a display jar. Photo: Chip Belden.
Just as macroinvertebrates are members of a stream ecosystem, we humans are also members of different systems. We have an impact on the things around us. There are things that we can do to help our systems and there are things we do that harm the systems we rely on. We can pollute, take resources, and ignore the lands or we can be stewards of the lands we love and protect. Being stewards connects us with the systems we are a part of, and it reminds us how we are connected to the animals and plants around us. Everything we do impacts the world around us. We hope our impacts will bring healthier streams and hundreds of macros for years to come!

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