Benthic Macroinvertebrate Monitoring: The Hidden World Within our Streams.
(Our team sorts macroinvertebrates from the Flint River)
Streams are much more fascinating then we give them credit for, there's an entire hidden world located within them. While we notice the bigger species like fish there are even smaller species that call streams home, macroinvertebrates, but what are they exactly? Benthic ( or bottom dwelling) macroinvertebrates are small aquatic animals and the aquatic larval stages of insects that spend either all or most of their time in or around water. They are often found attached to rocks, vegetation, logs and sticks or burrowed into the bottom sand and sediments. Species such as such as crayfish, dragonfly and stonefly larva, silverfish, clams/mussels, snails, etc. These species are important food sources for larger predators like our more commonly noticed fish species.
Macroinvertebrates are considered "bio-indicators"because they can help tell us the health of the particular stream. They are reliable indicators because they spend all or most of their lives in water making them 1) easy to collect 2) differ in their tolerance to pollution in the stream. Having limited mobility they have the capacity to take in the effects of any stressors they are exposed to over time. Generally, streams in healthy biological condition will support a wide variety and large amounts of macroinvertebrate species. On the other side tolerant species or very little diversity or abundance may indicate a less healthy stream.
For more information on benthic macroinvertebrates please visit the EPA's website below or your local DNR website!