Monitoring Methods: Biotic Index

Two volunteers search through a white basin for macroinvertebrates

Searching through a basin of macroinvertebrates

Monitoring Methods

When Do You Monitor?

Time Needed

Equipment Needed

Complete the biotic index twice each year; once in the spring and once in the fall.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Up to 45 minutes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other suggested equipment:

  • Magnifying glass or hand lens
  • Plastic cups
  • Latex/plastic gloves

 

 

 

Collecting and Analyzing Your Sample

Habitat types in a stream in order of macroinvertebrate diversity
Habitat types in a stream in order of macroinvertebrate diversity

Here is a brief synopsis of the process. 

  1. Collect a total of three samples from your stream site, collecting from at least two different habitats, starting with the most diverse habitats (riffles) if they are present at your site.  See inset at right. The three samples are all combined in one basin.
  2. Sort the macroinvertebrates.  Place one of each unique organism you see in the white basin into the ice cube tray. The biotic index is based on the presence or absence of each macroinvertebrate, so you do not need to count a total number of any organisms.
  3. Identify the macroinvertebrates, paying particular attention to those that are pictured on your data recording form.  You may find others not on your form and they are not included in the biotic index, so you can ignore them.
  4. Circle on your data recording form the macroinvertebrates found at your site.

 

lined paper  Specific directions on how to sample from the different habitat types as well as directions on what to do after you have collected your samples are in the fact sheet "Macroinvertebrate Biotic Index" Links to an external site..

 

Video Demonstration

 

Watch this video to learn WAV's biotic index method.