Monitoring Macroinvertebrates

Why should we monitor macroinvertebrates?

Benthic macroinvertebrates are immobile for most of their lives. In their larva and pupa stages, they are stuck underwater, between a rock and hard place or on the bottom of the stream or river or lake. They only get to fly and mate as adults the last few days of their lives. But as aquatic bugs, they need a place to hang on and hide out, where they can find their favorite food nearby.

Benthic macroinvertebrates react differently to changes in the health of the stream. Some are tolerant to pollution or temperature changes, while others are not.

Collecting and recording the changes in macroinvertebrates is an easy and cost effective way to measure the health of a stream.

By August or September streamflows have been stable for some time allowing invertebrates to reflect not only habitat conditions and hydrologic conditions, but also water quality.

An index period (August or September) helps everyone to plan on a specific time to sample, so all agencies, groups, schools have comparable data.