This past week students from West Linn High School came out to Abernethy Creek to do some surveys of macroinvertebrates living in the water. What are macroinvertebrates? Let’s break this word down: macro the greek prefix meaning “large” in: a prefix meaning “no” vertebrate: a word scientists use to describe the presence of a notochord (essentially a backbone), so altogether in plain everyday English, a macroinvertebrate organism is a large-no-backbone organism. In even plainer everyday English, a macroinvertebrate is in essence a bug. Taking samples and surveys of the bugs living in aquatic systems, such as creeks, are a really great tool for restoration ecologists to determine how healthy that system is. The more abundance and diversity of pollution tolerant individuals, the healthier the stream, it’s as simple as that. Macro samples can also give you a more accurate idea of health rather than chemical tests. Water chemistry may be constantly changing as the stream flows while these little bugs are constantly in the stream and will be affected by fleeting changes in chemicals. Also, you don’t need expensive equipment, you don’t need toxic chemicals, just a little know-how and an eye for identification.
With the spot of rain we had last week, Abernethy was flowing a little too high for West Linn students to get a good sample of the bottom-dwelling individuals, so students took nets and swept the vegetation along the banks to see what kinds of little critters are living along the banks, we found some interesting things! Good news: students found some caddisfly and mayfly larvae, both of which are considered pollution intolerant organisms. Other interesting things found were: young crayfish, scuds, water boatmen, aquatic earthworms, and water mites. We also managed to catch some fish: sculpin and a young lamprey! These were exciting to see, however they were not pertinent to our survey. Why? Fish aren’t invertebrates!
The West Linn Green Team did an excellent job doing the surveys and were excited about the whole process from netting to identification despite the drippy weather. We look forward to hearing about finding even more varieties of invertebrates in the stream as the work these students have been doing at this site all year continues to improve the stream quality.