Benthic Community

Benthic Habitat


Benthic macroinvertebrates are tiny aquatic creatures, large enough to be seen with the naked eye, but small enough that a microscope is often needed for identification. Some spend all of their life as bottom dwelling organisms (e.g., Scuds), and others spend a portion of their life on land (e.g., Dragonflies and Mayflies). These tiny creatures are the base of the food web upon which most of the fish communities in Fawn River depend.


During our restoration project on Fawn River we have independently collected data regarding the effects of the Sand Wand™ on the benthic community. We sampled the sediment-laden bottom before restoration, and then followed up at the exact same location a few days after and continued at intervals over several weeks.

 Click here to learn more about our Field Collection Protocol.

Benthic Sample


Prior to our restoration efforts, there was only minimal benthic activity, and it remained minimal for the first few days after clean up. However, within 2 weeks, a new community of pollution sensitive and somewhat sensitive macroinvertebrates (i.e., mayflies &  scuds) began to appear in the cleaned gravel. Within only eight (8) weeks after the gravel bottom was restored, a very large population of macroinvertebrates requiring high quality habitat had moved into the new homes created by the nooks and crannies within the clean gravel.


Why are macroinvertebrates important?

A healthy ecosystem includes thriving benthic communities. Macroinvertebrates play a vital role in stream ecosystems, both as a food source and as consumers of algae and other organic matter. According to the Environmental Protection Agency aquatic macroinvertebrates are good indicators of stream quality because:

    • They are affected by the physical, chemical, and biological conditions of the stream.
    • They can’t escape pollution and show the effects of short- and long term pollution events.
    • They may show the cumulative impacts of pollution.
    • They may show the impacts from habitat loss not detected by traditional water quality assessments.
    • They are a critical part of the stream’s food web.
    • Some are very intolerant of pollution.
    • They are relatively easy to sample and identify.

Benthic macroinvertebrates are commonly used indicators of river ecological condition that can be adversely affected by fine sediment accumulation. For benthic invertebrates, sedimentation means the loss of habitat variability, quality and quantity.


One of the major goals of the restoration is to remove the sediments choking the Fawn River’s bottom, thus restoring the gravel habitat for macroinvertebrates, which will allow larger populations of macroinvertebrates to thrive and eventually lead to a healthier fishery.

Fawn River Trust