Sampling For Benthic Macroinvertebrates

I had a great morning out on the creek yesterday, taking some Entomology students out to sample benthic macroinvertebrates in Copeland Creek. This project is a true win/win: I’m getting data for a long-term monitoring study of the creek, and the students are fulfilling a service learning requirement for their biology course.

Before I go into the details, let me take a quick step back for some definitions, for anyone who might not be familiar with some of these terms: Macroinvertebrates are animals without backbones that can be seen with the naked eye (“macro” = large), and benthic refers to the ecological zone at the bottom of a body of water, in this case the creek bed. Entomology is the scientific study of insects, and they were our primary focus, although we’re looking at other invertebrates as well, including arachnids (spiders, and their kin), worms, and maybe even some crustaceans, like crayfish, if we happen upon any of them.

What we’re doing is pretty straightforward: I’m having them follow the same protocols our Restoration Ecology students developed last semester, so we can add to that data set. Copeland Creek is seasonal, and doesn’t have running water for part of the year (including the period of time when last semester’s sampling was done), so I’m particularly interested in having data taken at different times of the year.

Copeland Creek
Copeland Creek

Yesterday, we reviewed the protocols in lab, and brainstormed some ideas about how to format our data collection forms. Then I sent them out into the creek to (literally) get their feet wet. They sampled for an hour, and we’re planning to collect at least one more set of data next week, and possibly a third set, as well. Right off the bat, though, we noticed a BIG different in both abundance and diversity of aquatic inverts, compared with what they found last semester. We sampled in the same general area, but in the fall, there’s just a small pool that holds water year round. This time of year, the creek is running quite nicely.

I really enjoyed being out on the creek, and my students seemed to enjoy it as well. It’s not a hard sell . . . getting to wade into the creek and catch stuff and get school credit for doing it? It’s a pretty sweet gig. 😀 Once we’d finished sampling, we preserved all our samples in alcohol, but we didn’t even try to ID most of them. We’ll key them all out at once, after we’ve finished all our collecting trips.

More soon . . . we’ll be meeting again next week!


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