Jump to main content.

Invertebrates as Indicators

More about:

Aquatic invertebrates live in the bottom parts of our waters. They are also called benthic macroinvertebrates, or benthos, (benthic = bottom, macro = large, invertebrate = animal without a backbone) and make good indicators of watershed health because they:

Some benthos are found more often, and in larger amounts, in waters that are generally clean, or unpolluted by organic wastes. Without too much organic matter, the waters usually have lots of oxygen for the benthos. This use as an "indicator" of water quality has been occurring for many years. For example, stoneflies are often considered to be clean water benthos. But when thinking about worms and midges, water quality professionals often view these as indicators of dirty water, especially in rivers and streams.

Invertebrates as Indicators

Unfortunately, it is not always a clear decision to make. Oxygen is only one factor affecting the benthos. Others include toxic chemicals, nutrients, and habitat quality. Some types of stoneflies may actually be found in waters that are not so clean, and likewise some types of worms and midges can be found in cleaner waters. So it is important to understand that there are some more complex methods to make these types of decisions, and to determine whether waters are healthy or polluted for aquatic life. Depending upon the type of aquatic environment, such as standing waters like lakes and wetlands, the categories of clean, somewhat pollution tolerant, and pollution tolerant don't necessarily apply.

Look at these links for specific examples of how benthos are used as indicators:

Note: all sites below link outside of EP's websiteExit EPA Disclaimer

Biological Indicators | Aquatic Biodiversity | Statistical Primer

Local Navigation

Jump to main content.