Which is why she was so excited to search for macroinvertebrates as part of our recent Trout in the Classroom activity. Messy, wet fun with interesting, tiny creatures living on the banks of the stream? Sign her up!
Macroinvertabrates have no backbones, but are large enough to see with the naked eye. In a stream ecosystem many are immature insects or larvae. They serve as important food sources for larger organisms, and as a bioindicators to scientists studying the health of a stream.
Investigating macroinvertebrates shows children the amazing biodiversity lurking just under the rocks in a river, helps them understand the connections between species in an ecosystem, and is just plain fun. It also gives children the opportunity to practice their skills of observation and categorization. These are fundamental skills for the study of biology, and science in general.
First thing you'll need is a kit, like the one below.
Here's what it includes:
- A plastic bin -- Great for larger organisms like crayfish or minnows, as well as acting as a carry all.
- Towels -- You know you're going to get wet, right? Plan ahead.
- Trowels and spoons -- Perfect for digging and sifting through soil in the riverbed.
- A fish net -- Because it's fun to catch small fish and similar creatures. Quick little buggers! Also good for sifting through debris.
- A foam egg carton or ice cube tray, white -- Perfect to separating and temporarily storing invertebrates while you categorize them.
- A ruler -- Helpful when trying to use a field guide to identify an organism.
- Magnifiers -- Get up close and personal.
- Pippettes/Eyedroppers -- to place water into your tray or collect algae samples.
- A flashlight -- Light can be dim under trees on some riverbanks. Bring your own light.
- A guide -- I like dichotomous keys, like this free one. These types of guides are really easy for kids to use. They're like "choose your own adventure" novels, but for science! (Make sure you put your guide in a sealed plastic bag to keep it safe in wet conditions.)
Beyond that, you just need to get out there and explore! Keep a journal. Take pictures. Get wet and muddy. Get to know what lives in the stream or pond near you. You'll be amazed at all the little creatures you never noticed before!
Once you have a good sense of what's there, you can use that information to evaluate how healthy your stream is. The number, diversity and types of creatures living there all hold clues. Many areas have citizen science programs where volunteers can help catalog macroinvertebrates, providing important information for ecologists and scientists.
And please, be sure to put the amazing creatures back where they belong when you are done. They deserve gentle treatment and respect.