This is Tim Toad with WDIRT filling in for the dirt on conservation.
I’m on assignment today at the Stream Flood Festival in Swift Bend Creek. The festivals are held just after a hard rain has occurred, and encompass the whole community.
I’m talking today with Mary Mayfly, a local resident here in Swift Bend.
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Tim Toad: Miss Mayfly, tell us a little about yourself.
Mary Mayfly: I am a small insect that spends most of my time in the creek; I have six legs that can cling onto most slippery surfaces, feathery gills along my body, and three long tails. I have a humble home underneath rocks in the stream.
I spend most of my time looking for bacterial cells to eat; while I crawl and dart around trying to avoid everything. You see, I’m small and will only get to be about an inch before I leave the water to be an adult, so everything wants me.
Tim Toad: Why did you choose to live here in Swift Bend Creek?
Mary Mayfly: I enjoy the fast-paced lifestyle of moving water, with all the runs and ripples it keeps my gills full of air. The water here is cool and clear with plenty of food to eat and the best part is, plenty of my friends live here, too.
I will only live where the water is clean and clear. I can’t stand pollution; I could actually die from it.
Tim Toad: Miss Mayfly, I understand that you’re not even an adult yet. Is that true?
Mary Mayfly: Why, yes, it’s true. The first couple months of my life, I get to spend in this wonderful stream, but soon a day will come when I will leave this world behind. I will reach the water’s surface, molt and set off to find true love.
Unfortunately, I know my fate and that is to mate and die, but it will all be worth it if my children carry on.
Tim Toad: Thanks, Mary, you tell a lovely story.
This is Tim Toad signing off from Swift Bend Creek, until the water rises again.
* * *
The interview with Mary Mayfly gives us a glimpse of her life cycle that many other aquatic bugs go through.
Most aquatic insects live in the bottom of our streams, rivers, lakes, and wetlands. They are also called benthic macroinvertebrates, and are good indicators of a water’s health because they live in the water for all or most of their lives, differ in their tolerance to amount and types of pollution and stay in areas suitable for their survival, to name a few.
Pollution sensors
These aquatic macroinvertebrates are grouped into three categories based on their sensitivity levels to pollution for the sole purpose of defining the water quality.
Class 1 Organisms are pollution sensitive. They are associated with good water quality. They cannot tolerate pollution well. Large numbers of these animals are observed only when good water quality is present.
Class 2 Organisms are somewhat pollution tolerant. They can with stand water pollution better than Class 1 organisms. Expect to see more of these animals when the water quality ranges from good to moderate.
Class 3 Organisms are pollution tolerant. They are tolerant to even higher levels of pollution than Class 2. When we see many of these animals, poor water quality is generally the reason.
Water quality
When monitoring a stream for good water quality, one method involves collecting a sample of macroinvertebrates from the body of water you want to study. Identify the organisms and give the water quality a rating.
Water quality ratings of excellent, good, fair and poor are based on the pollution tolerance levels of the organisms found and the diversity of organisms in the sample.
A stream with excellent water quality should support organisms from all three pollution tolerance groups but with the majority being from class 1.
Unfortunately, it is not always an easy decision to make. Oxygen is not the only factor affecting the invertebrates. Others include chemicals, nutrients, and habitat quality.
Some types of benthic bugs may actually be found in waters that are not so clean. So it is important to understand that there are more complex sampling methods needed to make these types of decisions, and to determine whether waters are healthy or polluted.
(Joe Lehman is a wildlife specialist/technician with the Guernsey Soil and Water Conservation District.)
